A650 IS KAP Parameters

I did some more ground-level experimentation with my A650 at lunch yesterday. This, in conjunction with my testing from last week and this week, can be summarized:

• The A650 IS can do ground-level IR photography, but under sunny-16 conditions, I'm getting 1/6 second exposures. Without modifying the camera to remove the IR blocking filter, I won't be doing any aerial IR photography with it. I have a Hoya R72 infrared filter on order.
  
• The A650 IS has some UV response as well, which I tested through a Schott UG-1 filter. Unfortunately this filter also has a big IR leak which I can't readily filter down. Without further testing I'm not willing to shell out the money for a UV bandpass filter. (These are not cheap.)
• The A650 IS works remarkably well at altitude. Because of the long focal lengths involved, a wide-open aperture works fine. The optics on the A650 IS can handle this without introducing unacceptable optical aberrations.
• At the shutter speeds I can get during the day, I don't think image stabilization is helping all that much. This is still an open question since I haven't tested it in the air, of course, but ground testing supports this. I do think IS will help me shoot in lower light, though, so sunset and night-time KAP may be an option whereas it wasn't with the Coolpix 5600.

The daytime shots I used to build the vertical panorama in my last post were at 1/640 sec shutter, wide-open aperture, and ISO 80. I can't really improve on that. The shots as they came off the camera were a little "hot", though. On the Coolpix I used -2/3 EV exposure compensation. From ground shots yesterday, I think a similar exposure compensation would work well on the A650 IS as well.

So here's the final setup I'll be using for my upcoming tests with the AuRiCo controller:

• Shutter Priority Mode (Tv)
  
• Exposure set to 1/640 seconds
• -2/3 EV exposure compensation
• ISO floats, clamped at ISO 200 (this is normal for the camera)
• Aperture floats, no limits

I still need to tune the timing parameters on the AuRiCo to make sure I get the image overlap I need in order to stitch. That will happen today or tomorrow during lunch, if the weather holds.

I'm still waiting on some bits for my camera, namely the Hoya infrared filter and the 58mm adapter tube. Once these are in I get to start playing with one other fun item: I've never hoisted a circular polarizer onto an aerial camera. I wonder how the reef would look with no sky reflection at all!

Tom

Bittersweet Realization

After a number of comments on my recent panoramas on Flickr, I read up a little more on Autostitch, the software I've been using, and found some options I hadn't really explored. I also pawed around in the pictures I took that day, and found that for one of the panos I had an additional image at the bottom and at the top that I hadn't used. Instead of a three-image pano, I could try my hand at a five-image pano.

The result was well-worth the hour and a half it took the computer to assemble it. The final cropped image came in at 3815 x 9242 pixels. At 150 DPI I could print it six feet high and not risk losing any detail.

On the one hand I'm elated that I chose so well on a replacement camera for my KAP rig. On the other hand I felt a pang of sadness. A 4x5 negative, scanned at 2400 DPI, comes out only slightly larger on the long axis. A double-row pano would easily cover the resolution available in a 4x5 negative. And at roughly $15 per shot for a sheet of Fuji Velvia plus E6 processing, it's also going to be cheaper in the long run. If the kite line is steady enough to hold the 4x5 KAP camera steady, it's also holding it steady enough for massive panoramas like this one.

So on the one hand the A650 IS upgrade is heralding a whole new chapter for me, but its also probably spelling the end of my experiment with 4x5 KAP. I'd still like to fine tune my 4x5 setup, but I don't think my heart will be in it any more.

Meanwhile I still have to come up with a better set of camera parameters for the A650 IS, and then I have a whole list of places I need to go fly. There's a lot of catching up to be done.

Tom

First Photogenic Results

I took my A650IS KAP rig out to Anaeho`omalu Bay on Monday, and had my first real KAP session at a photogenic location. But before launching into the results, first a confession:

The Nikon Coolpix 5600 is a really nice camera for someone looking for a straightforward point and shoot. It's actually got more than most point and shoot cameras offer. But at heart it still wants to do what it thinks best, and doesn't really offer the user a lot in the way of camera controls. Nonetheless, I did a lot of KAP with mine, and got a lot of good shots.

But I found that using it had fuddled my brain somewhat. After I posted pictures from my first flight with the A650, one of the other KAPers pointed out that my shutter speeds were fairly slow. He suggested putting the camera into shutter priority mode and setting the shutter speed to 1/640 sec. Aperture and ISO could adjust to compensate.

...

Duh...

...

It's funny, I use a DSLR all the time, and almost always think in terms of aperture priority or shutter priority. When I'm not using one of those two modes, I'm in manual mode trying to dial things down even finer than that to get just the right exposure.

But with my KAP rig, I'd really started treating it like a point and shoot camera simply because the camera I had bolted to the rig was a point and shoot. ARGH!

So when I went to Anaeho`omalu Bay, I put the camera in shutter priority mode at 1/640 sec exposure time. There was not one blurry picture in the lot. Not one. I do think the gain on the detector got bumped a little more than I like, so the images are a little noisier than I'm after. But I can fix that either by using CHDK's RAW mode for image storage, which would reduce the effects of compression on an already noisy image, or I can fix the ISO under 200 and bump the shutter speed down a little.

In any case the results were fantastic. I did several panoramic sequences that stitched beautifully. One was a repeat of a previous image I took with the Nikon, only this time done as a vertical pano:

The original image is over 6000 pixels high. At 150 DPI, that means I can make a print from that image 40" tall. Even with my large format photography, I've never actually printed anything larger than 36".

I guess I'm sold on digital photography now. Took me a while, but I'm sold.

Tom

Poor Man's IR Filter

Back in the day when most folks did black and white photography, the title of this post probably would've made sense. Not so much any more. But just in case you have a stash of Wratten filters lying around, this trick might work for you:

It's crosses 50% cut-on at 770nm, and passes 85% at max transmission. It's not the best IR filter in the world (the Hoya 72R cuts on at 720nm and has better overall transmission.) But if you already have the Wratten filters lying around, it's a freebie. Also, unlike many infrared filters there's no UV leak, so you're getting straight infrared on your detector.

Yes, the infrared picture I took in my previous post was taken with this stack. It really does work!

Tom

Digital Infrared

In the days before digital, it was possible to do near infrared photography using film. There were, to my knowledge, only two commercially produced films that did infrared. One was a Konica film (I think... could be wrong) and the other was Kodak High Speed Infrared, or HIE. In the days of the sprocket film counters, anyone could shoot infrared. You loaded it in the camera body and ran it like a normal film. Almost...

But when I first started shooting infrared I found out that even back then, modernization had caught up with me and caused problems. The Canon EOS A2 body didn't use a sprocket wheel to count frames as you advanced film. It used a really nifty arrangement with a photodiode and an LED. "An LED" you ask? "Wouldn't that expose the film?" Of course not! The clever Canon engineers used an infrared LED, so black and white and color film aren't exposed to any wavelength they can't handle! How ingenious!

"But what about HIE?" Yeah, that was the problem. The 800nm IR LED exposed HIE right in the wavelength range it's the most sensitive. So a 35mm negative (24mm x 36mm) became somewhat shorter (roughly 18mm x 36mm) because a wide swath was blasted by the LED.

So I got an older Canon EOS body that had a sprocket counter. It worked great, but other handling issues with HIE made it less than attractive. Most films have what's called an "anti-halation layer" on the back of the film. It's a fancy way of saying, "This is here to keep light from spreading." The plastic medium used for film is an excellent light pipe. Once light gets in, it bounces around spreading itself all over the place. For films without the anti-halation layer, this makes for haloes around bright objects. (Yes, "anti-halation" means "no haloes".)

Because HIE is so insensitive to light overall, an anti-halation layer would've made it unacceptably slow and even harder to use. So Kodak skipped the anti-halation layer, and used the light pipe effect of the film to make it more sensitive to light. It worked! In direct sunlight I was able to shoot it as if it were an ISO 125 film. And without the anti-halation layer, infrared pictures had an etheral otherworldly feel to them that's hard to capture any other way.

But eventually enough was enough. Because there's no anti-halation layer, any exposure to direct light could easily expose a third of the roll. So you had to load the camera in a dark room or inside a dark bag. It also tended to go bad fast, so you had to get it developed quickly. Most labs wouldn't touch the stuff, not because it was particularly gross or anything, but because it was a pain to handle. So eventually I gave it up and quit playing.

Until I went digital.

The first digital camera I ever got, a Nikon Coolpix 950, turned out to have really good infrared response. This should come as no surprise to anyone familiar with CCD technology. CCDs are sensitive from about 400nm out to about 1100nm, with the bulk of their sensitivity being between 700nm and 1100nm. This region is also known as the near infrared. (Well, the very near infrared.)

Given that, almost all digital cameras should have phenomenal infrared response! True, but they don't. Because letting in all that infrared light would make for some really weird photographs. Rather than have people complain, digital camera manufacturers include an infrared blocking filter in most of their cameras. Some filters are more effective than others. The one in the 950 wasn't all that effective, so by putting an infrared filter on the lens I was able to do infrared photography with comparative ease.

The only catch is the 950 was only a 2.5 megapixel camera. Still, given the grainy nature of HIE, that's actually more information than I could ever get out of an infrared film picture.

Times change, new cameras come and go. The day came when my wife and I traded in all our 35mm film bodies for a digital SLR, a Canon 20D. Hot diggity! Here was a chance to do infrared with a real camera! Aaaaah, but it was not to be. The Canon 20D uses a CMOS detector. Between the detector and the IR blocking filter, it has practically no sensitivity at all beyond about 720nm. So when I tossed my infrared filter on the end of the camera, absolutely nothing happened. It was like having the lens cap on.

I gave up on the idea of infrared photography for many years. I tried with the Nikon Coolpix 5600, but it had response similar to the 20D. I really thought it was done and gone.

So I was a little intrigued to learn that the A650IS has decent infrared response, and even some response in the UV! On a whim I picked up one of the IR filters from work and held it in front of the lens. It could see! So when I got home I pulled out my trusty IR filter and tried a shot.

Success! The black sky, the bright white clouds, and the ghostly rendering of vegetation all indicated I was getting infrared response rather than UV. It looked almost exactly like an HIE picture, minus the haloes.

I haven't found a way to test UV response yet, but we've got some UV filters at work I can use to at least verify that the camera can see out there. That's next.

My first thought on seeing this picture come out was, "I can't wait to do infrared from the air!" Well, yes, but it probably won't happen. The IR response of the A650IS is good enough for tripod shots, but at 1/6 second at f/4 aperture, it's not fast enough to make decent handheld or KAP shots. The Nikon 950 would've done a better job. Scott Armitage, who makes the DuneCam KAP control and video downlink system, has had really good results with a Pentax Optio S4, which seems to have similar sensitivity to the Nikon 950 while providing a much higher resolution image.

So no aerial IR for me. But still, it's nice to have the option again on the ground.

Tom

First Flight with the A650 IS

Against my better judgement, I didn't wait until the lens barrel arrived. I took my KAP bag, the new rig, and an 833g dummy weight out to the soccer fields in town and gave it a go.

First, a word about the wind in town: It's far more chaotic than what I'm normally willing to fly in. This is because of Waimea's proximity to Kohala Mountain. The wind spilling off Kohala is turbulent, chok full of gusts and lulls, making Waimea a pretty rotten place for doing kite aerial photography. Nonetheless, it's these same characteristics that make it a great proving ground for new kites and KAP rigs.

I spent the first hour flying a dummy weight. The rig weighed in at 833g, roughly 230g heavier than my old rig, but still considerably lighter than the 4x5 box camera.

Water bottles make great dummy weights for testing loads aloft. Put in enough water to equal the weight of the thing you're testing, and away you go! For this one I had to use a 1 liter bottle because the smaller ones I'm used to using simply didn't hold enough water. I tested it on my 6' rokkaku, and later my Flowform 16. For dummy weight testing I used the FF16 with 15' of fuzzy tail. But later I added an extra 15' of tail to slow down the movements of the kite.

With the extra tail on the kite settled down and flew straight enough that I wasn't afraid of having it go into a nose dive. After a brief hunt for the 1/4"-20 screw to hold the camera onto the rig, I put it up into the air.

The next few pictures were uploaded at the full 4000x3000 resolution to Flickr. They're unedited, straight off the camera. Most of the pictures I post here have had significant color balancing, exposure leveling, and rudimentary sharpening applied to them before posting. These have not. They're straight off the chip:

Feel free to follow the link on any of them to see the full resolution image.

Since this is a holiday weekend, I hope to get out at least once more and go somewhere a little more photogenic. The testing is done. Time to move on to doing kite aerial photography with this camera!

Tom

KAP Rig Conversion

I took the plunge and modified my KAP rig to take my new camera. Before going into the whos and whatfors, first some side-by-side comparison of the cameras themselves:

The Canon A650 IS is significantly larger than the Nikon 5600. It's also significantly heavier. With two AA batteries installed, the Nikon weighs in at 185g. With its four AA batteries installed, the Canon weighs in at 388g. This bumps the overall weight of my KAP rig by just over 200g! By far the heaviest component of the rig is now the camera itself. So much for lightweight rig design!

The tripod socket on the A650 is plastic, which doesn't endear it to me. I've already broken out a plastic tripod socket on an old Nikon Coolpix 950. I later replaced the broken socket with an aluminum one I manufactured in the shop. But it's sad that I had to. Since the Canon will be subject to a fair bit of stress in the air, this is something to keep an eye on. It's also a good reason to have a safety tether on the camera (which I did with the Nikon 5600 as well!) and to have additional support in the form of a Velcro strap to hold the camera firmly into the cradle.

Early on I made a lens hood for the Nikon 5600. Initially the idea was to keep stray light off the optics in order to reduce lens flare. But the real utility of the hood is that it protects the camera's fragile optics barrel from impact damage. Hard nose-down impacts are a very very real risk with KAP gear. The barrel, which weighs in at just over 10g, was cheap insurance.

The Canon Powershot A650 IS has a really neat feature I like a lot. It has a removable bezel around the lens that can be replaced with a hood similar to what I made for the Nikon. I've ordered a hood that ends in a 58mm filter thread. Since I don't really use the UV filters I've got in my DSLR bag, one of them is going to find a new home on my KAP camera. I doubt I'll fly this rig until the barrel arrives.

One of the other features I really like about the A650 IS is the reversible LCD. In the air, an LCD really doesn't do much but drain the battery. So for flight the LCD will be turned off and folded flat against the camera for protection.

I didn't want to have to make massive changes to the whole KAP rig, so I decided to only make changes to the cradle itself. This is what I started with.

And this is what I ended up with.

In addition to the change in camera, I had a few requirements for the design:

• I wanted to be able to access all of the camera's top controls easily, without obstruction.
• I wanted camera removal and installation to be dead-easy.
• I didn't want to increase the overall weight of the rig any more than was strictly necessary.
• I didn't want to modify the Brooxes BBKK hardware more than necessary (if at all!)
• I didn't want to do anything that would risk damaging my new camera!

This design met all of those goals, though it did mean manufacturing a new shutter servo bracket.

With the camera removed you can see the felt lining on the cradle. The bump on the back is there to keep the camera pointed straight forward. There's a slight bulge on the hinge side of the Canon's LCD that makes it not lie perfectly flat when the LCD is closed. The bump in the felt touches the camera only on the flat areas, and lets it sit straight.

All of the controls on the top of the camera are accessible when the camera is mounted in the cradle. Most notably, the power button is very easy to get to. This was not the case with the rig setup I used for the Nikon 5600. It's a welcome change.

One of the real surprises was how much mass is in the optics barrel assembly. When powered off, the balance point of the rig is slightly behind the pivot points of the cradle. When powered on with the lens extended, it shifts the balance enough to make the rig almost completely neutral. The bayonet-mount lens barrel should just about make things even out completely.

As I indicated earlier, I'm planning to wait for the lens barrel to arrive before hanging my rig from a kite line. So for the moment I'm grounded. But once I get airborne, the fun will really start!

Tom

Canon A650IS

My refurbished Canon A650IS camera showed up in my mail box this morning. Pardon me while I

YAHOOOOOO!!!!!

Ahem. All better now. Anyway, as I was saying: My A650IS came in. Earlier in the weekend my wife picked up a 4GB SDHC card for the camera, and some weeks ago I picked up an adapter tube and wide angle adapter lens from a friend. The adapter hardware was originally for a 700-series Canon, and that's where I got my first disappointment: The bezel on the A650 is quite a bit larger than the 700-series cameras. So I found one for the 650 on Ebay, and bought it. It should be here in a couple of weeks.

The adapter tubes mount to the bayonet ring on the front of the PowerShot cameras, and end in a 58mm thread. So with the new tube the wide angle lens should still work fine. I'm hanging onto it. This also means I can put a 58mm UV filter on the end of the tube along with a lens hood, and completely protect the camera's optics while it's in the air. But that's a story for another post.

Even though I've got a CHDK build for the camera, ready and raring to go, I opted not to confuse myself this early in the game. So please bear with me for not talking about CHDK in this post. I'm just not ready for it yet.

The size of the detector is impressive. It's a 4000x3000 chip. I took a three image panorama using the panorama assist function (which is pretty cool!), and wound up with an image that at 150 DPI is good for 60"x20". Cripes that's a lot of data.

Higher pixel count chips typically have higher noise characteristics. So I tested the noise level on a tree with bright blue sky behind it. This had bright highlights, dark shadows, large areas of smooth sky, and large areas of highly textured, high contrast subject. Up to ISO 200, the camera is remarkably good. Above that the smooth sky areas stay clean (probably a testament to the Digic III processor), but the shadow areas start to suffer. Since a lot of my aerials are done above open swaths of lava rock, I probably can't push it over ISO 200 without serious penalties.

The camera offers spot metering mode, which is really really nice. When shooting with my 4x5, I typically drag along a DSLR to be a backup camera and a meter. Problem is, our 20D doesn't offer spot metering. So shooting with the zone system has more or less been out of the question. But the A650IS not only has spot metering, it also reflects reality very very closely. I tested a couple of situations under sunny-16 conditions, and the numbers were spot on (pun intended.) I now have a spot meter for 4x5 work! Yay!

Though I'm not planning on using it heavily, the camera does offer a movie mode that's impressive. 640x480 with audio, and nary a glitch. The IS functionality really helps with this, but I've seen enough aerial video to know it will be choppy no matter what I do. (A fellow KAPer posted a list of tools he uses for taking excess motion out of his video. I plan to run some KAP videos through it to see what I can do.)

It's about 120g heavier than my Coolpix 5600, so my rig weight will go up accordingly. This will bump up the minimum windspeed I can fly with each of my kites. I'll need to test this with a dummy weight to see what this will mean in the field. One danger with this is if it compresses the wind range of any one kite beyond safety. For example: My rokkaku has a top end speed beyond which the kite will behave more like a fighter kite, swooping and diving, and yeah, hitting the ground. If the useful range of the kite becomes just a few knots, I won't be able to fly this rig on the kite at all. So I may need to get additional kites to take full advantage of this. Time will tell.

I poked around at some of the images in Photoshop. One characteristic I was happy to test was the scale of image blurring. Every camera blurs the image somewhat. If they don't, they're not taking full advantage of their lens. Also, the image appears to be really noisy if there isn't some amount of blur. Essentially this is Nyquist sampling at work. You want roughly two pixels for each unit of resolution of the lens. If your lens can resolve 600 line pairs per millimeter, you want 1200 pixels per millimeter. In practice what this means is that there's somewhat less than a pixel of blur in the image. An easy way to test this is to do an unsharp mask, run the slider up to something like 500%, and play around with the blur circle size. At some point there will be a sharp transition between looking like it's doing nothing and looking like it's destroying the image. On the Nikon Coolpix 5600 that was about 0.3 pixels. Turns out the A650 is about the same. (So is the Canon 20D, so it looks like the Canon engineers and Nikon engineers follow similar design rules. Cool!)

A neat feature of the viewfinder is when you review or play back images you've taken, pixels that are saturated will flash. This lets you know if you're killing your exposure. Not that I'll have an eye to the viewfinder when the camera is up on a kite, but it's nice to have a camera with an LCD big enough to really review my images with. And that's one nice way to find out if the exposure is good or not.

So what tests are next? I have a couple I'd like to do:

The first is to do some side-by-side IS / no-IS shots. I can do this manually on the ground, but in the air I'd like to set up a CHDK script so it takes one of each for every press of the shutter button. There has been a long-standing question regarding image stabilization in the KAP community, and at least in the case of Canon cameras this looks like a pretty straightforward way to test its utility for KAP. If the IS images are sharper/clearer/better, then IS helps. If not, it doesn't.

The second is to set up an exposure bracketing script so I can bang through a bunch of exposure offsets each time the shutter is tripped. For the Nikon I used -2/3 EV on all my exposures, and it seemed to take care of most of the over-exposure issues aerial cameras seem to suffer from. But my choice of -2/3 EV was more or less arbitrary. I'd like to be a little more careful this time.

Another that I'd like to play with is aerial HDR. The times I've mentioned this around habitual HDR fans, they tend to laugh. HDR images need to be completely lined up, or the techniques don't work. Since aerial cameras move around, surely that means HDR can't be done! Well... no. Images need to be lined up carefully for panoramas, too. And since I've done numerous aerial panoramas, some using several images, I'd argue that it works just fine. IRIS, a piece of imaging software for amateur astronomy, will pick up key points between multiple images, perform an affine transformation to line them up, and then store the aligned images as FITS files. IRIS will also translate FITS files to TIF files, so at that point they can be used in any photo manipulation software. Voila! Lined up images in a Photoshop or GIMP-readable format! Just what the HDR doctor ordered.

So there's plenty of testing to be done. Meanwhile I'm waiting for the adapter tube before mounting this camera on my KAP rig. There's nothing like a nose-down landing on an extended lens barrel to ruin your day. I don't plan to ruin mine.

Tom

One Last Fling (If the VOG Clears)

I got word yesterday that my camera had shipped. It should be here Tuesday or Wednesday next week. I'm STOKED. I've been playing with demo images from an A650 for the better part of a week, and I just can't wait to put it through its paces, both on the ground and in the air.

In the mean while I have time for one last fling with the 5600. If the VOG clears, that is. The trade winds have basically stopped, so all the gasses the volcano has been pumping out have just stalled over the island. Doctors have been reporting record highs in respiratory illnesses, and the air is so thick we've had to slow down for the drive home from work. It's been nasty.

No wind = no kites
No wind = VOG
VOG = lousy pictures anyway

I hope things change. I need the break.

Still no Tmax 400 film on order, but that's just a matter of time. Meanwhile I'm going to grab the rest of the Tmax 100 for use in my monorail camera, and ground the aerial 4x5 until I can order new film. I might get out to play with the thick air and a patch of trees I saw the other day. It was really ghostly looking, and the black and white film would work well with the monotone landscape. We'll see.

I'm really hoping it clears and Waipi`o valley has wind. I've tried now four times to fly there, and can't seem to get a camera above tree top level.

Anyway, it's late, I'm beat tired, and I'm rambling. Not a good combination for writing.

Night.

Tom

Camera Building - Self-Adhesive Velvet

I still need to make pivot hinges for the two outboard pulley blocks on my 4x5 KAP camera. While cruising around for small hinges, I ran across something really neat at Rockler: Self-adhesive velvet.

They sell it as a box liner, but one of the colors available is black! I can't think of a better way to line the inside of a handmade camera. It would act as a light blocker (velvet is typically pretty opaque) and it would make for a very non-reflective surface inside the camera. Perfect!

The only caution is that the adhesive they use is insanely strong. So once it's on, it's on. One of the reviews advised thinking through your handling methods carefully before using it. They were making sixteen boxes at once, and said the first one was 100% learning experience. The rest went smoothly. Their solution was to use pins and a pocket knife as positioning tools. The adhesive apparently sticks to finger tips like glue. In their words: "Think of duct tape adhesive on steroids."

A 12"x24" sheet is $8.95. That's enough to do the entire inside of a 4x5 box camera. Not bad considering the plywood to build the film back is easily twice that.

Probably not for this camera, but I know there's a next time. I'm already working on the design.

Tom

Spotting Photographs

If you're a photographer and you've never picked up a copy of Ansel Adams's "Technical Series", it's well worth the money and time. The "Technical Series" consists of four books: The Camera, The Negative, The Print, and Examples: Making of 40 Photographs. Be sure you get the works by Ansel Adams himself, though. A number of writers have come along after the fact and used Adams's name on their books, but it's Adams's own books I'm referring to here.

In his book, The Print, Adams devotes a lot of space to the process of spotting a photographic print. Let's face it, negatives are dust magnets. It happens when they're in the camera, which results in light spots in the negative that translate to dark spots in the print. It happens in the enlarger, which results in dark spots of dust on the negative that translate to light spots in the print. And don't think for a moment that the coming of the Digital Darkroom Age has taken large format photography away from all this. Dust shows up in scanners, too. Even digital SLRs get dusty inside, which is why so many of the new ones come with dust removal systems of one description or another.

But I'm getting off topic. Earlier today I spent about an hour in Photoshop spotting a scan of a negative I took back in 1996. That was one nasty scan. It had dark spots, it had light spots, it had hairs, it had everything you can imagine might get on a negative besides sneaker prints! But after some very careful application of the rubber stamp tool using a feathered brush, things finally started coming clean. The picture was uploaded, prints were set up, and everything seemed hunky-dory.

Except for this odd artifact at the lower edge of all the print previews... All of them showed an odd white band at the bottom. Real? Surely not...

It turns out it was. Chalk this one up to the digital darkroom: On a print enlarger, your projected image darkens the paper. Unexposed paper comes out white. So a slight discrepancy in the placement of the negative might bump in the white margins of the print, but it wouldn't make a glaring artifact like the one I saw.

But with a digital image, if the image is presented on a white background, black border artifacts show up glaringly. Likewise, if the image is presented on a black background, white border artifacts show up glaringly. There's no getting around it.

In the end I pulled the prints, re-cropped the image to get rid of the artifact at the lower edge, and re-posted it to re-create the prints.

As a matter of practice, it doesn't hurt to bump up the canvas size with a black border, then a white border while you're editing a picture, just to take a look at the edges. Window borders can hide details that can make or break an image while printing.

Tom

Characterizing a Large Format Lens

Ok, ok, so I didn't do a full characterization on a lens, though we do have all the tools I'd need to do that at work. But I wasn't after optical data, I was after practical information for use with the lens in the field. And that's precisely what I got.

When choosing and buying a large format lens, there are a couple of values that matter. One is focal length, which can be used to get field of view. If you're after wide-angle, something in the 75-90mm range is nifty. For a "normal" lens, something closer to 150mm is good. For a long lens, something in the 200-300 is handy. (A 300mm lens roughly translates to a 100mm 35mm lens.)

Coverage circle is another good number to know. Large format negatives are, well, large. If your lens won't cover the whole negative with a usable image, it's not going to do you much good. Ideally you want your coverage circle to be a little larger than your negative so you can use the camera's movements to good advantage.

I won't go into the camera movements in this article since it's a whole article of its own. Trust me that one of the real charms with a large format camera is that you can shift, tilt, swing, and otherwise move the lens and the film with respect to each other, resulting in all sorts of photographic advantages you don't get with a rigid body lens/camera combination.

Finally, if you're shooting color film another good bit of information to have is how well corrected the lens is. Older lenses were optimized for the blue since older emulsions were blue-sensitive, but had little to no sensitivity in the green or red. (Which is one reason why older photographs often had completely featureless skies... there were clouds, but the film rendered it as a uniform shade of overexposed.) But if you're shooting color, you need a lens that focuses at least the blue and red at the same distance behind the lens (achromatic). Ideally you'd like it to be corrected at more than two colors, preferably red, green, and blue (apochromatic).

But these are all decisions you make before you ever buy a lens. Let's say you have a large format lens already. It's mounted in a shutter, it has its own iris, and it's ready to go. Time to go take pictures, right?

WRONG!

I was using a large format lens I'd had for years, but I was getting consistently over-exposed negatives. Since each large format lens has its own shutter, the likeliest place to look was either that the aperture was not closing correctly, or more likely the shutter had drifted. So I put a chronograph on my shutter and clocked it. Oh how enlightening! This is what the data came out like:

• 1 sec = 1610-1624ms
• 1/2 sec = 970-1006ms
• 1/4 sec = 460-475ms
• 1/8 sec = 256-267ms
• 1/15 sec = 102-106ms
• 1/30 sec = 44ms (it really didn't drift at all)
• 1/60 sec = 27-29ms
• 1/125 sec = 10-12ms
• 1/250 sec = 6-7ms
• 1/500 sec = 3.9-4.5ms

Yup. My shutter is off by a full stop at every position. Dang. So noted, and I'll add a laminated card to my lens board to that effect tomorrow.

Another number that matters is where the lens's "sweet spot" is. Lens aperture is a mixed bag: At wide-open apertures, you're using every bit of glass in the lens, which probably isn't all that well corrected for spherical aberration. As you stop down, you use less and less of the glass, more toward the center of the lens where the curvatures are more forgiving, and typically your lens performance improves. But as the apertures get smaller and smaller, your image begins to suffer from diffraction effects from the aperture itself. By the time you get down to f/64 or smaller, diffraction will be causing more fuzziness than lens aberrations.

Most of the time the mid-point between these two curves will lie in the mid-range of the aperture ring. On my Canon 100mm macro lens, the sweet spot is at f/11. On my Canon 50mm f/1.4 lens, the sweet spot is out at f/16. It's worthwhile checking this number. In the event that you're taking a picture where depth of field isn't an issue, set your aperture at the sweet spot, secure your camera to a tripod or stand, and shoot away.

Of course depth of field is often the bigger consideration, and smaller (or wider!) apertures are called for. In that case do what needs doing. I shoot at f/64 with this lens a lot when I'm doing macro work. I really don't have a choice. On a lens like this, your depth of field disappears in a hurry at close focus distances. Having the smaller apertures available is a necessity.

But for landscape use, I often shoot at wider apertures. So what's the sweet spot on the lens in question? Between f/16 and f/22 it's pretty flat in terms of image resolution. On either side of that things do start to go downhill.

So now I know: My shutter's slow by a stop, and my lens likes f/16 to f/22. So for aerial shots, I'd ideally set my shutter to 1/500 (1/250 in reality), and shoot around f/22. So it sounds like an ISO 400 film like Tmax 400 (TMY) would be my best bet.

Better pictures through mathematics!

Tom

The Rule of Thirds

I recently had a practical lesson regarding the "rule of thirds" as it applies to photographic composition. I had some pictures not turn out the way I wanted, and when I analyzed them, the "rule of thirds" is where I kept winding up.

Before I get going with this, and before anyone gets their hackles up by my calling it a "rule", understand that, like the Pirate Code, photographic rules are guidelines more than actual rules. They were made to be broken. But breaking compositional guidelines willy-nilly, with no regard for the consequences, can result in sub-standard images (like mine were!) If you choose to break a compositional guideline, at least know what you're doing, and know you're doing it on purpose.

The "rule" of thirds states that you should put your photographic subject not at the bulls-eye center of your frame, but at one of the 1/3 points of the frame. If you divide your frame like a tic-tac-toe board, your subject should be at one of the intersection points of the tic-tac-toe lines. Here's a quick example:

This is a photograph of a flower, with the flower bulls-eye in the center of the frame. It might work as an illustration in a botanical textbook, but as far as putting it on the wall, it's a little lacking:


By re-composing the photograph with the flower off closer to one corner, we can totally change the feel of the picture:


The choice of corner is not arbitrary by any stretch. What if we put this one in the lower-right corner instead?


To me it feels like the flower is being crushed by the tree behind it!

The same compositional rules hold with horizon lines. It's the rare photograph that can stand having the horizon line bisect the image straight across the middle. Most of the time it helps to put the horizon line on one of the 1/3 lines. But which way to go? Depending on the composition, one will work better than another. Placing the horizon line high emphasizes the foreground. Placing the horizon line low emphasizes the sky. Depending on the weather, it can add a sense of freedom to the picture, or it can add a sense of foreboding if the weather is dodgy.

It was a horizon line rather than a flower that was giving me grief in this case. The film 4x5 camera I built for doing kite aerial photography can point anywhere from straight up to straight down, and can face all the points of the compass. But since there's no viewfinder to look through, all the composition has to happen on the ground. Last weekend I went out shooting, and came back with an odd lack of horizon lines. It's not that they didn't fall on the 1/3 lines, they weren't typically in the frame at all!

Since I have a model of my KAP camera in CAD, it's to CAD that I turned for the answer. I know the size of my negative, I know the focal length of my lens, so I did a quick exercise to find my field of view. I was amazed to find how small it was!


The blue angles represent the actual field of view of the camera. But the red angles represent the 1/3 angles of the field of view. They're tiny!

What I learned from all this is that a down-angle of only 6.65 degrees is enough to put the horizon 1/3 of the way down from the top of the frame. It also means that the tolerance for the suspension to hold the camera off horizontal is extremely tight!

I've added some compositional guideline stickers to the camera, and will be adding a bubble level to the top of the Picavet before the next flight. I could probably do with a much wider angle lens on this camera. But since the camera was built around the lens, that would mean building a new one from scratch. For next time.

Tom

More Fun with Vendors

In an earlier rant I went off the handle about shipping. This reared its ugly head about a week ago when my wife placed an order for that Canon Powershot A650IS. The one that was supposed to arrive today. But there's more to the story than just shipping and the fact that it didn't arrive today. It goes something like this:

Most camera shops won't ship via the US Postal Service. I've heard the same old wheeze so many times it makes me sick: "The postal service loses stuff!" In the whole time I've been living with a P.O. Box, I recall one parcel being lost. One. That's it. And considering the added cost of using one of the big carriers to get stuff out to where I live, out here in the middle of the Pacific, I still think I'm ahead.

My wife finally found a company that would ship USPS, but at the last minute their web site informed us it wouldn't ship to a P.O. Box. Grrrr! Ok, fine. Send it to work.

The next morning I had an email informing me my order was holding until a sales representative could get clarification on something. ??! I called them up, expecting problems with my credit card, problems with shipping, or something of that sort. "We see you've ordered a camera that doesn't come with a memory card. We are running a special on memory cards, and..." !!! Yes, they held my order so they could try to sell me a memory card. I told them I had a stack of SD cards, and to please push the order through.

I heard nothing from them for a week, so I decided to call and ask what was up. "We show that item is back-ordered for six to eight weeks." !!!!! "And when were you planning on telling me this?!" "I was about to send an email." Yeah... I bet... I told them to keep the order open, and ended the call.

So imagine my surprise when the email they sent informed me my order had been canceled! "Angry" is too mild a word to describe my mood when I saw that. "Livid" is getting closer.

So here's the plea: If you are running a business and someone orders a piece of equipment from you, please keep them informed of the order status. If you know an item is out of stock, please contact the buyer and let them know. And for heaven's sake, if the buyer gives you a direct order regarding their purchase, follow their instructions!

I placed another order for the camera from another vendor, and within ten minutes I had a confirmation e-mail with my order number, order manifest, shipping policy, expected delivery time, and a phone number I can use to contact them. That is what I call customer service!

I'm still looking forward to my new camera, but it'll be a little longer than I was expecting.

Tom

Answer to a Comment

db made a comment on my previous post regarding CHDK on the Canon A650IS, asking for more information. I tried to reply to the comment with another comment, but realized things were getting a little wordy. So here's the somewhat longer reply:

I'm still relatively new to CHDK, but from what I gather the best source for information is the CHDK Wiki. Something else I realize I utterly failed to say is that CHDK is a group effort involving lots of different people writing lots of different software for lots of different cameras based on the Canon Digic processors. As such, there are many many build of CHDK. Some work for some cameras, some work for others. Some include features that others don't include. The A650IS is a relatively new camera, and uses the Digic III processor, so it shows up in fewer builds than some of the older cameras, especially those based around the Digic II processor.

So the link in my previous post to CHDK should've said that this is the URL for the AllBest CHDK build, and includes one for the A650IS. There are many many other builds out there. The CHDK Wiki is the best place to find out more about them.

From what I gather, the real motivation for CHDK was to get RAW images off of cameras that supposedly did not offer them. But as people started poking around at the firmware in each of these cameras, all sorts of possibilities began to pop up, and CHDK expanded in scope. For me, RAW images are pretty low on my list of things I want to do with my A650IS. It's the other and sundry that really appeals.

One that I'm very interested in exploring is the whole idea of motion detection. I don't know if the AllBest CHDK build includes motion detection, but a number of other builds do. I get the feeling the motivation for the motion detection algorithm was lightning photography, wildlife, or things of this ilk where the operator wants to know when things move, and to have the camera take action when that event occurs.

For KAP the opposite is true. Most of the blurred images I get off my KAP camera are because of camera motion during the exposure. Only a handful of very low-altitude shots were blurry because of poor camera focus. So if there was a way to have the camera delay exposure until the camera was stable, it would be a boon.

Lots of ideas have been put forth to address this. Mostly they have to do with rig stabilization. By far the easiest is simply to build a rig that doesn't move around much. The whole idea behind the Picavet suspension and Christian Becot's variant on the pendulum suspension is to do just this: Make something that holds the camera steady. Brooks Leffler, Christian Becot, Mike Jones, and many others have taken this a step further, developing damping mechanisms that tend to take out what sway a rig might develop over time. Others, including me, have wondered if a six-axis inertial measurement unit could be coupled to the servos in a KAP rig to create active stabilization of the camera. (I've moved away from this idea after talking to someone about active stabilization of the gun in the M1A1 Abrams... it's anything but straightforward.)

But motion detection through CHDK offers a much simpler approach. Simply don't trigger until the motion on the detector calms down. The only changes to the actual rig are software changes, and most of the development has already been done through the development of CHDK. I know at least one KAPer is looking into this, but I haven't heard how the experiments have come out.

Another application of CHDK for KAP is the ability to take multiple exposures at multiple settings with a single press of the shutter button. When doing panoramas, it's very easy for the metering requirements to change radically from one angle to another. Sunlight, cloud cover, etc. make it almost impossible to take a single set of panorama exposures without having at least one dark band because some bright object got into the frame. If the camera is scripted so that it takes three, four, or even five exposures at different exposure compensation values, a more consistent panorama could be constructed simply by picking and choosing the appropriate exposures. Even more radical would be to use HDR techniques to fine-tune the dynamic range of each image in the panorama.

"But HDR images all have to be aligned!" one might claim. Absolutely! But so do stitched panoramas! Once you transform the images into a common coordinate frame, if the software will allow the individual transformed images to be manipulated, HDR becomes possible. And if the software won't allow for this, switch software! One of the programs I've used for astro photography is Iris, which will pick common features in multiple frames and perform an affine transformation on each of the frames to bring them into a common coordinate system. (Sound familiar?) The author, who's a mighty sharp fellow, realized this had utility outside of stacking astro photography images, and expanded it so it would work on normal daylight images as well. Because Iris gives you full access to all your frames at every step in the process, these transformed but un-stacked images could then be loaded into the software of your choice to do the HDR work.

Oh... and Iris happily works with RAW images! But I haven't checked to see if the RAWs produced with CHDK on the A650IS will work with it. Time will tell.

To answer the second question in the comment: Yes, I plan to post entries describing my experiences with the A650IS and with CHDK. My hope is that I will get to do experiments in each of these areas, post the results, and preferably post the CHDK script, the list of software tools I used to do each task, and a procedure for doing them. Hey, if I get to play, everyone else should, too! (And if anyone else is already working along these lines, I hope they have the same "share and share alike" philosophy.)

Tom

Accessories Before Camera

This is a first, even for me. I already have accessories for my A650IS, and I don't have the camera yet!

One of these is virtual. I downloaded CHDK for the A650IS. It's a scripting language that runs on top of the camera's Digic III processor firmware, and lets you do all manner of neat things, like scripting custom exposure bracketing modes, adding new menu options, shooting RAW files, etc. A number of KAPers use CHDK on their Canon cameras to script canned routines for getting anything from bracketed exposures to rapid-fire panoramas, and everything in-between. One particularly neat script looks for the +5V flag to go high on the camera's USB port, and use that to trigger an exposure. Voila, instant remote control over the shutter. It's neat!

But the accessory that came today is more hardware than software. A friend of mine has a 700-series PowerShot, and had an adapter tube and a wide angle lens for his camera. But he wasn't 100% happy with it, and was looking to unload it. I was more than happy to take it off his hands.

I have two reasons for this: First, the wide angle adapter, even though it has nasty barrel distortion and clips (not vignettes... clips) the corners, I'm happy to work with that in order to get larger panoramas.

But more important to me is the adapter tube. The PowerShot cameras have a bayonet mounted bezel ring around the lens that can be removed to install camera accessories like the adapter tube. This gives the tube a very firm mount on the camera body, and completely encloses the lens. At the far end of the tube is a 58mm filter thread. This is a convenient size considering all the filters I have for my DSLR have 58mm threads!

But the real benefit lies in the barrel itself. Talk to practically any camera repair shop, and they'll tell you that the bulk of the digital point and shoot DOA accidents involve the lens barrel. Most have telescoping lens assemblies that extend out of the camera body. Even a relatively soft tap at the end, say from a drop of six inches, is enough to destroy or horribly mis-align the optical assembly. A drop from six feet is enough to ram the optics back inside the camera, permanently stripping the motor/gearbox assemblies that handle focus and zoom. Instant "time to buy a new camera".

So having an armored barrel that completely covers the optics assembly is a really good thing! Especially if you know you'll be hanging the camera off a kite that can, on occasion, come down really really fast. I've had four nose-down landings with my Nikon Coolpix 5600 camera, but because I built my own barrel for its lens, it survived all four impacts.

It's good to know my new camera will have a fighting chance when it comes to nosedives. That would be a blog entry I'd hate to have to write.

Tom

A Diversion

Well that was short-lived! I sold another picture on Etsy, so I think I'll be keeping that gallery around after all. And I should probably do it the courtesy of adding some of the images I took during the World Wide KAP Weekend 2008. A couple of them turned out pretty well!

But something else is rearing its head, and I really can't ignore it. I've had three story ideas I've been tossing around for years, and I really really got the urge to start working on one of them in earnest. I'm grimacing as I write this, but the catalyst was watching Eragon.

I didn't finish the book when I first started it a few years ago. My wife did. When she saw the movie she was... well... unhappy is probably a kind term to use, but it applies. When she consented to watch it again with me, she admitted the movie really did an ok job of taking a long book and turning it into a 120 page story. (I have strong opinions on screenplays derived from novels, and tend to side with the screenplay writer. Have you ever tried to compact a 700+ page book into 120 pages of dialog? Give it a try some time. It's not trivial.)

One of the characters was just a little too close in temperament to one of the ones in my story. It really struck a chord. I have to get back on the story!

So I may be writing a little more in the evenings, and doing a little less of photography marketing. This is probably to my overall detriment since I'm not an accomplished writer, and have nowhere near the experience of Christopher Paolini. But the only way to get experience is to undertake the task. If he can, I can. Even if the story is only ever heard or read by my kids, that's fine. It's a story I will have passed on to brighten someone else's day.

I'm looking forward to it!

Tom

A Switch of Galleries

I'm coming to the conclusion that Etsy really isn't the right place to sell photographs. I don't think I'm going to pull things, but I do think it's an up-hill battle to get photography sold there. After reading a post where someone referred to someone selling products on Etsy that had been made on Zazzle, I took a look at Zazzle.

And...

Well...

That's actually really cool! And it answered some other questions I was having, like how do I get stuff printed on mugs and post cards? (Hey, I really am not too proud to put my pictures on mugs... I drink coffee.)

So I set up a Zazzle gallery. And lo and behold, once you upload a picture for print, the user can pick their own options, up to and including their choice in mat, frame, glass, media, etc. Cripes, they can take a single image and go from a $25 print up to a $500 monstrosity that will come in a semi. It's neat! And like Imagekind and Etsy, it lets you dial in your own numbers.

I started with four mugs, some mouse pads (soon to add more) and a bunch of aerial and ground prints. I'm going to poke around through my archives and see what other pictures lend themselves to the aspect ratio required for mugs, and post some more mouse pads tonight. They also do post cards, calendars, and even custom stamps! So I'm going to play up a storm, put some other product lines together, and see what I come up with.

I don't know if it'll result in anything really earth-shattering. I somehow doubt it. But I do think the Zazzle customer crowd is a little more geared toward shopping for photographic stuff.

It's also the first time I think I'm actually going to be comfortable pointing friends and family toward my stuff. Imagekind and Etsy really didn't lend themselves well to that. But this just might.

Time will tell...

Tom

World Wide KAP Weekend 2008

After an abortive attempt to go to the lighthouse near Kapa`au Town at the north end of the island, my son and I drove to Kona, ran some errands, and went north to Kekaha Kai Park. The beach at the north end of the park is a gorgeous spot, and if the winds are right it's rock-solid for flying a camera rig.

In addition to my digital KAP bag, I also brought my 6' rokkaku (which came in handy later in the day as the wind dropped), and my 4x5 KAP camera, the building of which has been chronicled here.

I wound up doing just about every form of KAP I can. I flew soft kites (Flowform 16 + fuzzy tail), framed kites (6' rokkaku), radio controlled KAP (my digital rig with Futaba radio), autoKAP (same rig with the AuRiCo), film (my 4x5 KAP camera), digital (the digital rig), and I closed by taking a set of glamor shots with the digital rig and AuRiCo on the line first, with the 4x5 camera below it, and me on the ground launching:





WAHOO! What a day! I got back, ran through my digital shots, managed to stitch a panorama, and developed film that night. Everything is up on the World Wide KAP Weekend Flickr group.

The 4x5 performed, but still not perfectly. I guesstimated at a sunny-16 exposure, even though it was slightly overcast. I managed to get two useful shots and one that was simply strange. More on that in a bit.

Of the two shots, one had too much motion blur and the other actually came out well. But it did hammer home the point that I need to switch from Tmax 100 (TMX) to Tmax 400 (TMY), and gain two stops. Those two stops would've been the difference between f/16 at 1/125 and f/16 at at 1/500. Could've been enough to save both pictures.

The strange shot was just... strange. It's completely uniformly somewhat but not fully exposed. I don't know how else to describe it. There's no pattern on the film from the film holder, so it's almost like it wasn't correctly installed in the first place. Even more strange, there's no sign of an exposure on the film. At all. Even on fogged film, you get something indicating the shutter tripped. I checked, and the shutter was tripped for all three exposures. It's a mystery.

The best explanation I can come up with is that I pulled the wrong dark slide. A 4x5 film holder holds two pieces of film, one on one side and another one on the flip side. Before exposing the film you have to remove the dark slide, which exposes the film to the back of the lens. But there are two dark slides, one for each side of the holder. If you pull the wrong one, not only is the film facing the lens still covered, the other sheet is now exposed!

On most 4x5 cameras, it would be obvious because there's only a ground glass between the exposed film and broad daylight. But there's no ground glass on the 4x5 KAP camera. It's a light-tight sheet of aircraft plywood. Still, there are enough light leaks around the spring back to the back side of the film holder, I could easily see its being exposed during the half hour the dark slide was out. Pity, though, it would've been a shot of the sandy part of the beach. Luckily, it's the same area my vertical panorama covered:





So I was a little disappointed not to get that on 4x5 film, but I can't complain. I still got the shot.

I've got a new list of changes to make to the 4x5 camera, and a change in film I need to make fairly soon. But the idea has been tried, the camera has been tested, and it really does work. Past here it's fine tuning and picking pretty subjects.

It was a good weekend.

Tom

A Weekend, A New Camera, and Another New Camera

This weekend is the World Wide KAP Weekend 2008! If you have a kite and a camera, join in! For more details, check out the KAP Discussion Forums. Of course everyone's welcome to do KAP anywhere, any time, no matter the occasion. But since KAP really is a worldwide activity, and since it's often hard for KAPers to get together to do kite aerial photography, this is a way for everyone, no matter where they are in the world, to join in a sense of togetherness, even if there isn't another KAPer for four thousand miles.

I was on an airplane most of the first day of the WWKW 2008, and didn't get to fly. But I plan to head out tomorrow with my digital KAP rig as well as my new KAP 4x5 camera and join in! It'll be a wonderful way to test out the new camera, and it's also a good way to say goodbye to my trusty Nikon Coolpix 5600 that has been the workhorse of my KAP experience thus far. Because...

My wife very kindly got me a Canon A650IS camera today. It's mailing out on Monday, and should be here by next weekend. This is the camera I've been looking at for so long, and is far better suited to doing KAP than the Nikon was. I'll report on it once it arrives and I have a chance to play with it.

Meanwhile, the most wonderful thing happened regarding the 5600: My son, who has accompanied me on the bulk of my KAP outings, has asked for a KAP rig of his own. Yaaaay! So I'm going to take the Nikon and build out a rig for him to use. Probably AutoKAP at first, but eventually I think he'd get a big kick out of a radio rig.

So I'm looking forward to the rest of the weekend, and to next week! Should be fun!

Tom

P.S. Seriously! Go fly a kite. And keep it soaring. Up through the atmosphere, up where the air is clear. And while you're up there, take a picture!

4x5 KAP Updates and Observations on LA

The 4x5 KAP camera is coming along. Still work to be done, but it's in far better shape now than it's ever been. It's a shame I can't use it right now, though.

I'm in Los Angeles, taking a UCLA Extensions course in Structural Dynamics. I have to say I'm really pleasantly surprised by the contents of the course. I thought it would be an overview of a lot of FEM/FEA software I don't have licenses for. Turns out the engineer presenting the course, Dennis Philpot, had much more useful ideas in mind. It's been a return-to-basics low-level class including materials I saw in my Newtonian Mechanics course, Electromagnetism (believe it or not... an LRC circuit looks a lot like a damped spring/mass system), Stellar Atmospheres (asteroseismology bears an odd resemblance to acoustic vibration), etc. Only difference? Instead of newtons, kilograms, and meters (or in the case of astronomy, grams and centimeters), the whole class is in feet and pounds. I have to laugh.

But the material is outstanding. It's a shame I'm still jet lagged. Focusing is hard, and only by really really shoving everything aside can I stay on top of what's being covered. Even so, at times I get lost and have to go back later to figure out just what the @#$% a particular second derivative is secondly derivating.

Still, it's providing lots and lots of food for thought. Like how to isolate the 6-DOF IMU on a quadracopter so it's not subject to vibration from the rotors. Like how to apply all this, plus the theory of vortex shedding, to the design of KAP rigs. (Yes, even in the class I'm thinking about aerial photography from a kite.) It's fun to think about the time periods involved with KAP, and to realize that most of the other people in the room don't go that low. It's fun!

But the one thing it's not is a grand flying opportunity for me. The wind has largely been dead, and what wind there was yesterday wasn't worth flying in. Here I've been in LA for two days, and I haven't even made it to the beach yet. I'm not sure I will.

For starters, I spend eight hours a day in class. What time I'm not in class I'm spending avoiding traffic. That really doesn't leave a lot of daylight time to fly. Wisely, my wife urged me to leave my KAP gear at home and not risk losing it to the TSA or baggage handlers (who could easily take it for any number of diabolical devices it's not.) So I'm KAPless in LA with barely a brain cell left to my name at the end of the day. Yet I still find the time to dream about flying. Ah well. Once a geek...

I should be back on-island Saturday, all things willing. I can't wait to see my family, and hope they pack my KAP bag and the 4x5 in the trunk. What can I say? Once a geek...

Tom