For better or worse, I entered a black and white photography competition. Rather, I should say I entered it three times. They didn't place any restrictions on the number of entries you can submit, but each one carries with it a $15 entry fee. Three seemed like a good number.
Whether it was a conscious choice or not, the three pictures I entered do a good job of demonstrating the kinds of photography I do. One was a large format macro shot, the second was a digital ground shot, and the third was a KAP shot. The large format shot started life as a black and white negative, but the other two had to be converted from color images. It was easy for the digital ground shot, but easier said than done for the KAP shot. In the process I learned that most of my KAP images really do need to be color in order to work. A handful can be used either way, and some, by the nature of the subject, already are black and white pictures. But for the theme of the competition, my choice took some work.
And in the end, I wound up shooting myself in the foot.
To be fair, this is my first photo competition. So I don't have a lot of experience to compare with. Still, the rules were unclear on several points, and I wound up hurting my chances as a result.
The way the rules read, photographers submit non-returnable prints or slides. Submissions are then reviewed by a panel of judges. The judges select which photos should be hung in the gallery, and inform the artists. The artists then make their final prints and mat and frame them for hanging. Once the photos are hung in the gallery, the photographers and general public are invited to view them.
A photograph may win the judges' award, the people's choice, the photographer's choice, and/or the grand prize. So they're judged at least three separate times. The rules don't explicitly say how the grand prize is decided, but my guess is it is a compilation of the points from the three rounds of judging, with the highest tally taking the prize.
Here's where it gets fuzzy, though. In reading and re-reading the rules, I get the feeling the judges' award is based on the submissions, not the hanging work. I chose to print my submissions on 8.5x11 matte photo paper rather than slides since that is the medium I intend to use for my finished pieces. But the finished pieces are intended to be printed 18"x24", with the matte and frame bringing that up to roughly 24"x32". So potentially two of the rounds of judging will be done on the 18"x24" size, and the third on a much smaller size.
Kinda wish I'd submitted slides, which are projected for the judges to view. Say what you will, the size of a photograph determines, to a large extent, the emotional impact it has with the viewer. Take your favorite Ansel Adams print and print it 5"x7". Hang it on the wall next to one of his more typical prints in the 36"x48" size. Which one grabs your eye? Which one takes your breath away? Ok, I really wish I'd submitted slides.
But such is life. I honestly don't think any of my pictures stand a strong chance of winning. I've reviewed winning photos from previous years, and it's a style of photography I really don't do. I also don't think I carry the clout, as a photographer, to wow the judges and public strongly enough to make them choose a photograph outside of their comfort zone.
My intention was not to compete so much as to get my work shown. Even if one of my pictures makes it to the gallery, I'm happy. It will mean someone is getting to see it. I do a so-so job of marketing my photos online, but I do a downright terrible job of marketing them locally. This is the first in several efforts to address that.
As a side benefit, all the photos hung in the gallery are up for sale. That's in the rules, too. In previous years, almost all the artwork in the gallery sells. So it's not only a nice marketing venue, it's also an opportunity to make a sale. Can't beat it. My goof-up isn't looking so bad now.
Still, I learn from my mistakes. Next year? I'm getting slides made.
Tom
Tuesday, September 30, 2008
Saturday, September 20, 2008
A Change in Direction
The past few weeks have been rough, both at work and as far as my hobbies are concerned. We had a failed mirror coating, and a thin coating on our second attempt shook our confidence in our process and our equipment. We've spent the past few weeks thinking through all the what-ifs, and ordering new supplies to replace what we used. Because of all this our secondary mirror's coating schedule had to be bumped, but not by enough to actually test our equipment in the mean time. We're going into it blind, not knowing if we'll get a good coating. Stressful? You bet.
In conjunction with this, the weather has been utterly uncooperative for photography. Every weekend, the wind dies and the volcanic gasses start piling up. At one point visibility dropped to less than a quarter mile. The view from my house, normally good incentive for me to get my camera and head out the door, was a uniform gray. On those rare days when the weather was clear, invariably something had already been planned, and photography wasn't part of it. Frustrating? You bet!
When the weather is bad, the only thing you can do is live with it. Read a book, surf the web, or look at other people's pictures to get new ideas of where to fly. I did a little of each. It didn't help.
I've known for some time there was a sameness to my pictures. But after surfing thousands of pictures of Hawai`i, I found there's a sameness to a lot of pictures taken here. It's because even with the variations from island to island, even with all the climates the Big Island has to offer, there are limits. You can only drive the same road so many times before it stops being something new. There are only so many times you can see the sun setting over the ocean before even a photographer says to himself, "Yep, seen that."
I need a change.
In a small way, at least, I do have a change coming up. Most of my KAP shots have been coastal, but there's a trip to map a heiau between Hualalai and Mauna Loa, and I've been invited to participate. Two of us will be flying KAP rigs over the heiau in order to gather the shots necessary for the photogrammetry software to do its thing and create the 3D model of the site. The altitude is of the site is almost a mile above sea level. Not enough to cause real problems, but enough to make wind requirements an issue.
I know I can fly my full RC KAP rig in ten knots of wind using my rokkaku. At 5000', that requirement goes up because of the thinner air. But the wind at the site rarely goes over 8 knots, so flying that rig is iffy at best. Since the shots required are all straight down, and since I need a lighter rig to fly, I made one specifically for the purpose.
It uses the same camera as my RC rig, a Canon A650 IS running CHDK. I've got an intervalometer script loaded on the camera, so it's a straightforward matter of dialing in the number of seconds between exposures, and sending the camera aloft. At just over 400g of mass in its ready-to-fly configuration, it's about half what my full RC rig weighs. And it packs small enough it will fit into a pocket of my KAP bag.
Planning the trip, building the rig, thinking through all the technical issues I'm likely to run into, it's all helped. But it's not really enough. I really need a more substantial change than that.
One thought I've been toying around with for the past six months is the idea of becoming a semi-professional photographer. I can't see myself making a living at it full-time, and I have no intention of quitting my day job, despite the heartache it's caused recently. But at the suggestion of a friend and fellow KAPer, I picked up a copy of Dan Heller's Profitable Photography in the Digital Age. It's a good book, and well worth the money. It also spelled out a lot of reasons why going semi-pro is probably not the right answer to the problems that have been dogging me. If anything, it would up my frustration level worse than it is now.
Today I was re-reading John Shaw's Business of Nature Photography, and came across one of his points about how to break into the nature photography business: publish articles that use your photography. I literally smacked my forehead! I know I'd read those same words years ago when I first bought his book, but for some reason I'd forgotten them.
A few years ago, I wrote some articles for Digital Machinist, one of the trade publications I take. I enjoy writing, and the articles were fun to do. I even published some pictures with them, though they weren't the greatest example of studio photography I've seen. I have some other articles lined up, but there's a big difference between doing machining and documenting machining as you do it. Photographing a machining process makes it take about ten times longer, and because you're constantly fiddling with the camera setup and the machining setup, it can be a frustrating way to get a job done. At some point I'll get back to those articles, but I'm not in a huge hurry.
Even after Digital Machinist had published my articles, it didn't occur to me that I'd done exactly what Shaw had recommended. Not until I re-read his book. The thought of applying this to my photography had simply never entered my mind.
But even I can put two and two together when they're put in front of me with a big neon sign. I live in a unique place. I do a fairly unique form of photography. And I know I can write since a publisher saw fit to print my work on more than one occasion. Hey, I can do this!
The next step, of course, is to come up with ideas for articles and to do market research into the publications likely to carry them. Travel magazines, airline in-flight magazines, photography magazines, and possibly even machining magazines are likely ones to try the ideas on. Travel destination articles, articles describing rig fabrication or camera fabrication, even educational how-to articles for teacher publications are all fair game.
The weather is a little better today, but I think it's the new hope for three hobbies I truly enjoy that's made for the change in outlook. Life is getting interesting again.
Tom
In conjunction with this, the weather has been utterly uncooperative for photography. Every weekend, the wind dies and the volcanic gasses start piling up. At one point visibility dropped to less than a quarter mile. The view from my house, normally good incentive for me to get my camera and head out the door, was a uniform gray. On those rare days when the weather was clear, invariably something had already been planned, and photography wasn't part of it. Frustrating? You bet!
When the weather is bad, the only thing you can do is live with it. Read a book, surf the web, or look at other people's pictures to get new ideas of where to fly. I did a little of each. It didn't help.
I've known for some time there was a sameness to my pictures. But after surfing thousands of pictures of Hawai`i, I found there's a sameness to a lot of pictures taken here. It's because even with the variations from island to island, even with all the climates the Big Island has to offer, there are limits. You can only drive the same road so many times before it stops being something new. There are only so many times you can see the sun setting over the ocean before even a photographer says to himself, "Yep, seen that."
I need a change.
In a small way, at least, I do have a change coming up. Most of my KAP shots have been coastal, but there's a trip to map a heiau between Hualalai and Mauna Loa, and I've been invited to participate. Two of us will be flying KAP rigs over the heiau in order to gather the shots necessary for the photogrammetry software to do its thing and create the 3D model of the site. The altitude is of the site is almost a mile above sea level. Not enough to cause real problems, but enough to make wind requirements an issue.
I know I can fly my full RC KAP rig in ten knots of wind using my rokkaku. At 5000', that requirement goes up because of the thinner air. But the wind at the site rarely goes over 8 knots, so flying that rig is iffy at best. Since the shots required are all straight down, and since I need a lighter rig to fly, I made one specifically for the purpose.
It uses the same camera as my RC rig, a Canon A650 IS running CHDK. I've got an intervalometer script loaded on the camera, so it's a straightforward matter of dialing in the number of seconds between exposures, and sending the camera aloft. At just over 400g of mass in its ready-to-fly configuration, it's about half what my full RC rig weighs. And it packs small enough it will fit into a pocket of my KAP bag.
Planning the trip, building the rig, thinking through all the technical issues I'm likely to run into, it's all helped. But it's not really enough. I really need a more substantial change than that.
One thought I've been toying around with for the past six months is the idea of becoming a semi-professional photographer. I can't see myself making a living at it full-time, and I have no intention of quitting my day job, despite the heartache it's caused recently. But at the suggestion of a friend and fellow KAPer, I picked up a copy of Dan Heller's Profitable Photography in the Digital Age. It's a good book, and well worth the money. It also spelled out a lot of reasons why going semi-pro is probably not the right answer to the problems that have been dogging me. If anything, it would up my frustration level worse than it is now.
Today I was re-reading John Shaw's Business of Nature Photography, and came across one of his points about how to break into the nature photography business: publish articles that use your photography. I literally smacked my forehead! I know I'd read those same words years ago when I first bought his book, but for some reason I'd forgotten them.
A few years ago, I wrote some articles for Digital Machinist, one of the trade publications I take. I enjoy writing, and the articles were fun to do. I even published some pictures with them, though they weren't the greatest example of studio photography I've seen. I have some other articles lined up, but there's a big difference between doing machining and documenting machining as you do it. Photographing a machining process makes it take about ten times longer, and because you're constantly fiddling with the camera setup and the machining setup, it can be a frustrating way to get a job done. At some point I'll get back to those articles, but I'm not in a huge hurry.
Even after Digital Machinist had published my articles, it didn't occur to me that I'd done exactly what Shaw had recommended. Not until I re-read his book. The thought of applying this to my photography had simply never entered my mind.
But even I can put two and two together when they're put in front of me with a big neon sign. I live in a unique place. I do a fairly unique form of photography. And I know I can write since a publisher saw fit to print my work on more than one occasion. Hey, I can do this!
The next step, of course, is to come up with ideas for articles and to do market research into the publications likely to carry them. Travel magazines, airline in-flight magazines, photography magazines, and possibly even machining magazines are likely ones to try the ideas on. Travel destination articles, articles describing rig fabrication or camera fabrication, even educational how-to articles for teacher publications are all fair game.
The weather is a little better today, but I think it's the new hope for three hobbies I truly enjoy that's made for the change in outlook. Life is getting interesting again.
Tom
Sunday, September 14, 2008
More on the Feather
So far my results with the KAP Feather are mixed. I flew in two spots with wildly different wind on two different days.
Day one was at Upolu Point in 20+ knot wind (closer to 22+ knot wind). I flew my Flowform 16 despite the wind speed, and managed to get good altitude, regardless of the thing "pulling like a truck" as Brooks Leffler described it. It's a good description! At the tail end of the flight I finally had to clip off to a fence post and walk the kite down with a carabiner. Even hand-over-hand, I couldn't get the thing down any other way.
I flew with the long pan axle, with and without the KAP Feather. In high wind like that, the KAP Feather tended to cause the rig to make small amplitude, high frequency oscillations. I put a lot of this down to tuning. The KAP Feather offers a lot of range for tuning simply by sliding the feather forward and aft on its central spar. I ran at full length, which was probably too much leverage for my rig.
Removing the KAP Feather resulted in larger amplitude, lower frequency oscillations. Pointing was still tough to determine, but the overall angular rate was lower, which resulted in fewer blurred shots. This is how I flew for the remainder of the day.
The second day was in my neighborhood, with Kona winds. These are typically more stable than the Trades we get here because the Trades tend to be stirred up from blowing over Kohala Mountain. Still, it made for a lot of oscillations, and I eventually took it off and flew without.
By the end of the day I removed the long pan axle from my rig and put the Picavet back on top of the pan axis gear box. Dang...
I'm not ruling out the KAP Feather. Far from it. I don't think I've given it a fair shake yet. But I also don't know if my digital KAP habits and flying requirements really jive well with it. I've already come up with a combination of camera settings and flying conditions that work well for me. I'll need to come back to the KAP Feather another time.
The jury's still out on my 4x5 camera, though. I do think it needs something along these lines to stabilize it, along with higher flying mass to offset its large cross-sectional area. There's a lot of exploration to be done along these lines. Only time will tell.
The incident tally for the day included one kite marked in a cat battle (rinsed, drying in my room now), one rig rolled about four times on the ground (thank goodness I got an extra set of Broox leg brackets!), and no real shots to show for it. Ah well.
Tom
Day one was at Upolu Point in 20+ knot wind (closer to 22+ knot wind). I flew my Flowform 16 despite the wind speed, and managed to get good altitude, regardless of the thing "pulling like a truck" as Brooks Leffler described it. It's a good description! At the tail end of the flight I finally had to clip off to a fence post and walk the kite down with a carabiner. Even hand-over-hand, I couldn't get the thing down any other way.
I flew with the long pan axle, with and without the KAP Feather. In high wind like that, the KAP Feather tended to cause the rig to make small amplitude, high frequency oscillations. I put a lot of this down to tuning. The KAP Feather offers a lot of range for tuning simply by sliding the feather forward and aft on its central spar. I ran at full length, which was probably too much leverage for my rig.
Removing the KAP Feather resulted in larger amplitude, lower frequency oscillations. Pointing was still tough to determine, but the overall angular rate was lower, which resulted in fewer blurred shots. This is how I flew for the remainder of the day.
The second day was in my neighborhood, with Kona winds. These are typically more stable than the Trades we get here because the Trades tend to be stirred up from blowing over Kohala Mountain. Still, it made for a lot of oscillations, and I eventually took it off and flew without.
By the end of the day I removed the long pan axle from my rig and put the Picavet back on top of the pan axis gear box. Dang...
I'm not ruling out the KAP Feather. Far from it. I don't think I've given it a fair shake yet. But I also don't know if my digital KAP habits and flying requirements really jive well with it. I've already come up with a combination of camera settings and flying conditions that work well for me. I'll need to come back to the KAP Feather another time.
The jury's still out on my 4x5 camera, though. I do think it needs something along these lines to stabilize it, along with higher flying mass to offset its large cross-sectional area. There's a lot of exploration to be done along these lines. Only time will tell.
The incident tally for the day included one kite marked in a cat battle (rinsed, drying in my room now), one rig rolled about four times on the ground (thank goodness I got an extra set of Broox leg brackets!), and no real shots to show for it. Ah well.
Tom
Thursday, September 11, 2008
Feather in the KAP
My KAP Feather came in today. Sorry, no pictures and no wild wind reports yet, but they'll be along shortly.
Prior to my ordering the KAP Feather, a discussion came up on the KAP forum about suspension stability vs. pan axle length. Because the KAP Feather puts a fairly large obstruction at the downwind side of the rig, it includes an extra long pan axle so the camera is positioned underneath the obstruction. So I now have a chance to try three configurations at once: Original, Long-Axle, and Long-Axle with Feather.
The ideal way to test this would be to get a 6DOF IMU and a data logger, and fly each of the three configurations under the same wind conditions. Mmmm... Not gonna happen. I can't shell out the $300+ for the IMU, and the only person I know who owns one needs it for their own project (a quadracopter). But I do have the next best thing: a camera.
While developing the 4x5 box camera, Henry Jebe suggested mounting my digital camera somewhere on the rig so I could shoot video during a flight. The videos I've shot from a KAP rig have been pretty wobbly because of all the rig motion, but as Henry pointed out, what better way to measure the wobbliness! Give a nice ground-level pano of the scenery, you should be able to get angular measurements between landmarks, and not only get a good idea of the overall motion of the rig, but be able to turn it into angular rates. Fly each of the three configurations, and you have a good idea of what each one will do.
One encouraging point is that Mike Jones from Jones Airfoil, the designer and manufacturer of the KAP Feather, shoots HD video from his rig. Given my own experience with low-def video, if he's getting enough stability to shoot HD, the Feather will do an admirable job. I'm looking forward to trying it in the field this weekend.
The one question I still have to answer is transport. Right now everything packs down into a backpack, and is quick to set up in the field. The longer axle on the pan axis won't fit into my pack. So chances are I will have to come up with some sort of release system so I can remove the Picavet from the top of the rig, and remove the KAP Feather from the Picavet. Starting to get complicated.
But it really doesn't have to be. I just need to find the right way to work it, and it'll be fine.
So the next question is what to do with the 4x5 rig. I ran the idea of adding stabilization to it past Mike Jones, and it looks like he's got some ideas. Work's been too busy for me to do much with it, but I hope to talk to him in the next week or so and get some direction.
Lots to look forward to.
Tom
Prior to my ordering the KAP Feather, a discussion came up on the KAP forum about suspension stability vs. pan axle length. Because the KAP Feather puts a fairly large obstruction at the downwind side of the rig, it includes an extra long pan axle so the camera is positioned underneath the obstruction. So I now have a chance to try three configurations at once: Original, Long-Axle, and Long-Axle with Feather.
The ideal way to test this would be to get a 6DOF IMU and a data logger, and fly each of the three configurations under the same wind conditions. Mmmm... Not gonna happen. I can't shell out the $300+ for the IMU, and the only person I know who owns one needs it for their own project (a quadracopter). But I do have the next best thing: a camera.
While developing the 4x5 box camera, Henry Jebe suggested mounting my digital camera somewhere on the rig so I could shoot video during a flight. The videos I've shot from a KAP rig have been pretty wobbly because of all the rig motion, but as Henry pointed out, what better way to measure the wobbliness! Give a nice ground-level pano of the scenery, you should be able to get angular measurements between landmarks, and not only get a good idea of the overall motion of the rig, but be able to turn it into angular rates. Fly each of the three configurations, and you have a good idea of what each one will do.
One encouraging point is that Mike Jones from Jones Airfoil, the designer and manufacturer of the KAP Feather, shoots HD video from his rig. Given my own experience with low-def video, if he's getting enough stability to shoot HD, the Feather will do an admirable job. I'm looking forward to trying it in the field this weekend.
The one question I still have to answer is transport. Right now everything packs down into a backpack, and is quick to set up in the field. The longer axle on the pan axis won't fit into my pack. So chances are I will have to come up with some sort of release system so I can remove the Picavet from the top of the rig, and remove the KAP Feather from the Picavet. Starting to get complicated.
But it really doesn't have to be. I just need to find the right way to work it, and it'll be fine.
So the next question is what to do with the 4x5 rig. I ran the idea of adding stabilization to it past Mike Jones, and it looks like he's got some ideas. Work's been too busy for me to do much with it, but I hope to talk to him in the next week or so and get some direction.
Lots to look forward to.
Tom
Saturday, September 6, 2008
Filters in my Bag
My new Hoya CP filter came in yesterday. It was overcast, so I didn't have a good opportunity to try it out. It's has multi-layer AR coatings on each face, so it should have less ghosting than the Tiffen I've been using, and the filter is only 5mm thick, so I might not even get the vignetting I sometimes got with the Tiffen. Time will tell.
As I tucked it into my KAP bag and put the Tiffen back in the DSLR bag, it got me to thinking: The filters I keep in my bag have sure changed!
When I started off with 35mm, I kept UV filters on the ends of my lenses. I thought it a necessity, a way to protect my lenses against smudges and scratches, and at that stage it probably was. But over time I learned how to be paranoid about my lenses, and the UV filters did little more than filter out UV light. Eventually they came off, and spent more time in the filter bag than on the lenses.
Early on I got a circular polarizer. That Tiffen CP I used for KAP is the same one I got back in '95 for 35mm. It's probably time to change it out since the optical surfaces aren't what they once were, but it's still in use. Case in point, I keep one in each camera bag. The only bag that doesn't have a CP is my 4x5 bag, and I'd be interested in changing that.
I shot enough B&W film through 35mm cameras that I got a fairly good set of Wratten gel filters for B&W work. #25 red, #47A blue, a #90 viewing filter (for me, not the camera) were my main ones. I also got a #12 deep yellow, #8 yellow, and #58 green which didn't see as much use, but were good to have. When I started shooting more 4x5 B&W than 35mm, these moved to the 4x5 bag. It turns out the #58 green is good for shooting black lava rock beaches, so it will probably find its way into the 4x5 KAP bag.
In the days of film, you couldn't white-balance to correct for color shifts. I kept filters for fluorescent and tungsten lighting to shift their white point closer to outdoor conditions. I shot a lot of color slide film, balanced for outdoor shooting. So for the lab shots I did at the time this was a big boon. With digital cameras, they're really not necessary any more. And with my film work now being only B&W, they went in the filter bag with the UV filters, probably never to be seen again.
One set of filters I haven't removed is the split ND filters. These are rectangular pieces of acrylic that are clear at one end, and have a neutral density tint at the other, with a transition between the two in the middle. Slide film has about five stops of dynamic range. If you're shooting a scenic, and the sky is three stops lighter than the foreground, metering the foreground puts it in the middle of your dynamic range, and puts the sky at a blown-out white. Pop a two-stop split-ND filter on the end of the lens and slide it down until the transition puts the ND over the sky and the clear over the foreground, and the sky will come out one stop lighter than the ground. Neat stuff!
"But with digital, you don't really need to do that!" Well, yes you do. Or rather you should consider it. True, you can dodge and burn in programs like Photoshop and Gimp, but you only get so many bits per pixel. Even if you have any texture left in the sky at all (which at three stops you wouldn't), chances are it'll look posterized by the time you're done with it.
"But with HDR, you don't need to do that, either!" True, and the next time you try to do an HDR wildlife shot of a running deer, let me know how it turns out. I'm not pooh-poohing HDR. I think it's a great technique. But to say that one technique invalidates another one is the wrong way to look at it. Each has its place, and the split-ND filters still live in my DSLR bag. (Heck, I can't wait to try HDR with split-ND!)
Why use filters at all? That's actually a really good question. Everything you stick in front of a lens will affect the final image quality. Filters are planar-planar optics, which when stuck in a converging beam will introduce spherical aberration into the optical system. Unless you have a really good reason to use one, a filter only degrades your image. In one of John Shaw's books he posed a really simple test: Unless you can vocalize a particular photographic reason to use a filter, don't use one.
For example: "The reflection off the vegetation in this shot is washing out the color, and de-saturating the image. A circular polarizer will let me cut the reflections and bump the color in the leaves."
Another: "My digital camera has seven stops of dynamic range. The foreground in this shot is three stops darker than the sky. Metering off the foreground will blow out the sky. A 2-stop ND filter will bring it within the range of the camera's sensor, and bring out the texture in the clouds."
But here's the worst: "My friend always said to keep a polarizer on your lens." Errr...
Each time I use a filter, it's a conscious choice to address a particular photographic problem I'm facing. Daylight balanced film under fluorescent lighting used to be one I had to deal with. I don't now, so that filter has gone by the wayside. Flying my KAP rig over a reef and wanting to cut the surface reflection is one I deal with these days, so keeping a circular polarizer in the bag is entirely justified. B&W and the Wratten gels are as natural a choice as when Ansel Adams was using them decades ago. Be aware of what you're doing when you choose to use a filter, and make sure it does what you intend.
Tom
As I tucked it into my KAP bag and put the Tiffen back in the DSLR bag, it got me to thinking: The filters I keep in my bag have sure changed!
When I started off with 35mm, I kept UV filters on the ends of my lenses. I thought it a necessity, a way to protect my lenses against smudges and scratches, and at that stage it probably was. But over time I learned how to be paranoid about my lenses, and the UV filters did little more than filter out UV light. Eventually they came off, and spent more time in the filter bag than on the lenses.
Early on I got a circular polarizer. That Tiffen CP I used for KAP is the same one I got back in '95 for 35mm. It's probably time to change it out since the optical surfaces aren't what they once were, but it's still in use. Case in point, I keep one in each camera bag. The only bag that doesn't have a CP is my 4x5 bag, and I'd be interested in changing that.
I shot enough B&W film through 35mm cameras that I got a fairly good set of Wratten gel filters for B&W work. #25 red, #47A blue, a #90 viewing filter (for me, not the camera) were my main ones. I also got a #12 deep yellow, #8 yellow, and #58 green which didn't see as much use, but were good to have. When I started shooting more 4x5 B&W than 35mm, these moved to the 4x5 bag. It turns out the #58 green is good for shooting black lava rock beaches, so it will probably find its way into the 4x5 KAP bag.
In the days of film, you couldn't white-balance to correct for color shifts. I kept filters for fluorescent and tungsten lighting to shift their white point closer to outdoor conditions. I shot a lot of color slide film, balanced for outdoor shooting. So for the lab shots I did at the time this was a big boon. With digital cameras, they're really not necessary any more. And with my film work now being only B&W, they went in the filter bag with the UV filters, probably never to be seen again.
One set of filters I haven't removed is the split ND filters. These are rectangular pieces of acrylic that are clear at one end, and have a neutral density tint at the other, with a transition between the two in the middle. Slide film has about five stops of dynamic range. If you're shooting a scenic, and the sky is three stops lighter than the foreground, metering the foreground puts it in the middle of your dynamic range, and puts the sky at a blown-out white. Pop a two-stop split-ND filter on the end of the lens and slide it down until the transition puts the ND over the sky and the clear over the foreground, and the sky will come out one stop lighter than the ground. Neat stuff!
"But with digital, you don't really need to do that!" Well, yes you do. Or rather you should consider it. True, you can dodge and burn in programs like Photoshop and Gimp, but you only get so many bits per pixel. Even if you have any texture left in the sky at all (which at three stops you wouldn't), chances are it'll look posterized by the time you're done with it.
"But with HDR, you don't need to do that, either!" True, and the next time you try to do an HDR wildlife shot of a running deer, let me know how it turns out. I'm not pooh-poohing HDR. I think it's a great technique. But to say that one technique invalidates another one is the wrong way to look at it. Each has its place, and the split-ND filters still live in my DSLR bag. (Heck, I can't wait to try HDR with split-ND!)
Why use filters at all? That's actually a really good question. Everything you stick in front of a lens will affect the final image quality. Filters are planar-planar optics, which when stuck in a converging beam will introduce spherical aberration into the optical system. Unless you have a really good reason to use one, a filter only degrades your image. In one of John Shaw's books he posed a really simple test: Unless you can vocalize a particular photographic reason to use a filter, don't use one.
For example: "The reflection off the vegetation in this shot is washing out the color, and de-saturating the image. A circular polarizer will let me cut the reflections and bump the color in the leaves."
Another: "My digital camera has seven stops of dynamic range. The foreground in this shot is three stops darker than the sky. Metering off the foreground will blow out the sky. A 2-stop ND filter will bring it within the range of the camera's sensor, and bring out the texture in the clouds."
But here's the worst: "My friend always said to keep a polarizer on your lens." Errr...
Each time I use a filter, it's a conscious choice to address a particular photographic problem I'm facing. Daylight balanced film under fluorescent lighting used to be one I had to deal with. I don't now, so that filter has gone by the wayside. Flying my KAP rig over a reef and wanting to cut the surface reflection is one I deal with these days, so keeping a circular polarizer in the bag is entirely justified. B&W and the Wratten gels are as natural a choice as when Ansel Adams was using them decades ago. Be aware of what you're doing when you choose to use a filter, and make sure it does what you intend.
Tom
Friday, September 5, 2008
Digital Zone System
Ever since getting into large format photography, I've used the zone system to set up my exposures. This is a system of sensitometry used and taught by Ansel Adams, and was the culmination of years of testing and in-the-field experience by him and his colleagues. By being aware of the dynamic range of your film, and knowing what you could do in the darkroom to compress or expand that range, it let you meter a scene and very precisely predict how it would be rendered on film. I won't presume to go into a full description of the zone system because I can't do as good a job as Adams himself. For that, see his book, "The Negative".
I admit I'm lazy when it comes to digital photography, though. I don't use the zone system, and I slip into complacency when metering, trusting the camera's electronics to do a better job than I can. This is a terrible way to operate! The camera may have a very good idea of how to render a particular tone as an 18% gray, but it has no clue whatsoever what the photographer had in mind for a scene!
Here's a good example: You're shooting a sunset, and want to get a foreground palm tree to show up as a silhouette against the glowing sky. So you whip up your camera, half-press the shutter button to meter the scene, and expose. Trusting to fate, you go about your business, only to find out later that the tree is rendered as a muddy, dim, tree-colored mess, and the sunset sky is blown out. Grrr! Photoshop can fix this by fiddling around with levels and curves, but the resulting picture looks almost Technicolor because the dynamic range has been squeezed around so much.
Better to meter the scene, know how bright the tree is, and set your camera so you know the tree will come out black, and the sky will be rendered in all its glory. To get there, though, you first have to know the dynamic range of your camera.
Regardless of whether you're shooting film or digital, the way to test the dynamic range of your detector is to shoot a textured, uniform-toned subject at various exposure settings, and look at the shots. Below a certain exposure value, it should render as pure black. Above a certain exposure value, it should render as pure white. Between those values is the dynamic range of your detector. Film, CCD, CMOS, doesn't matter.
Most B&W films exposed and developed normally give you about ten stops of dynamic range. You can tweak the developing to change that, but that's the base point. Color films typically gave you about seven stops of range. Color slide, about five. But it's always best to test it yourself and not trust to fate! I always tested a new film before taking it out in the field. Why should digital be any different?
I set my camera, a Canon PowerShot A650 IS at ISO 100, and pointed it at my trusty textured white target, a block of styrofoam. (Hey, better for it to wind up in my studio than in a landfill!) With the camera set on manual and the aperture fixed at f/8, I ran exposures from 1/2000 to 2 seconds in 1 stop increments. The results were a little surprising.
Something else that can be had from a test like this is the response curve of the detector. So starting at 1/2000, I took the central 1000x1000 patch of image and looked at the mean value of intensity for the whole patch:
+0 0.41
+1 1.42
+2 3.68
+3 9.60
+4 20.38
+5 39.97
+6 72.46
+7 112.97
+8 154.53
+9 209.67
+10 248.84
+11 255.00
Keep in mind that each additional stop of exposure value should double the amount of light hitting the detector. Given that, you can see my camera is not the most linear thing in the world. So if you're using a digital camera as a quantitative photometric device, be forewarned! These things may not be linear! If in doubt, test your gear.
Armed with this information and a spot meter (which the A650 IS has, thank goodness) I can start making better decisions about metering and exposure. My A650 will never replace my monorail, but that doesn't mean I can't apply the same care and attention to detail when using it.
Tom
I admit I'm lazy when it comes to digital photography, though. I don't use the zone system, and I slip into complacency when metering, trusting the camera's electronics to do a better job than I can. This is a terrible way to operate! The camera may have a very good idea of how to render a particular tone as an 18% gray, but it has no clue whatsoever what the photographer had in mind for a scene!
Here's a good example: You're shooting a sunset, and want to get a foreground palm tree to show up as a silhouette against the glowing sky. So you whip up your camera, half-press the shutter button to meter the scene, and expose. Trusting to fate, you go about your business, only to find out later that the tree is rendered as a muddy, dim, tree-colored mess, and the sunset sky is blown out. Grrr! Photoshop can fix this by fiddling around with levels and curves, but the resulting picture looks almost Technicolor because the dynamic range has been squeezed around so much.
Better to meter the scene, know how bright the tree is, and set your camera so you know the tree will come out black, and the sky will be rendered in all its glory. To get there, though, you first have to know the dynamic range of your camera.
Regardless of whether you're shooting film or digital, the way to test the dynamic range of your detector is to shoot a textured, uniform-toned subject at various exposure settings, and look at the shots. Below a certain exposure value, it should render as pure black. Above a certain exposure value, it should render as pure white. Between those values is the dynamic range of your detector. Film, CCD, CMOS, doesn't matter.
Most B&W films exposed and developed normally give you about ten stops of dynamic range. You can tweak the developing to change that, but that's the base point. Color films typically gave you about seven stops of range. Color slide, about five. But it's always best to test it yourself and not trust to fate! I always tested a new film before taking it out in the field. Why should digital be any different?
I set my camera, a Canon PowerShot A650 IS at ISO 100, and pointed it at my trusty textured white target, a block of styrofoam. (Hey, better for it to wind up in my studio than in a landfill!) With the camera set on manual and the aperture fixed at f/8, I ran exposures from 1/2000 to 2 seconds in 1 stop increments. The results were a little surprising.
- 1/2000 (+0) was black. Pixels ranged from 0,0,0 to 1,1,1 in value. Down in the noise.
- +1 stop had some value (up to 2,2,2) but nothing I'd call texture. Noise.
- +2 stops started to show real texture. Call this the beginning of the dynamic range.
- +3 - +10 showed texture.
- At 1 second and beyond (+11 stops), the image was maxed at 255,255,255. Beyond the range.
Something else that can be had from a test like this is the response curve of the detector. So starting at 1/2000, I took the central 1000x1000 patch of image and looked at the mean value of intensity for the whole patch:
+0 0.41
+1 1.42
+2 3.68
+3 9.60
+4 20.38
+5 39.97
+6 72.46
+7 112.97
+8 154.53
+9 209.67
+10 248.84
+11 255.00
Keep in mind that each additional stop of exposure value should double the amount of light hitting the detector. Given that, you can see my camera is not the most linear thing in the world. So if you're using a digital camera as a quantitative photometric device, be forewarned! These things may not be linear! If in doubt, test your gear.
Armed with this information and a spot meter (which the A650 IS has, thank goodness) I can start making better decisions about metering and exposure. My A650 will never replace my monorail, but that doesn't mean I can't apply the same care and attention to detail when using it.
Tom
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