Category Archives: Question

Shooting Through a Fence

In the last lesson, I talked about shooting at the zoo under difficult circumstances and how to break the problem down into manageable pieces. One of the problems that TJ faced was that there was a fence between him and the subject. I promised to take a few sample shots through a fence and show what effects different apertures had on the image.

The following images were all shot with a Canon Digital Rebel XT and the Canon 50mm f/1.8 lens, also known as the nifty fifty. I chose it because I wanted to be able to open up the aperture in order to blur the fence as much as possible. Here are three sets of images that show how the fence looks from different distances at different apertures. I apologize for not finding more interesting subjects, but these were taken during a quick stop at the Port of Oakland when I was late for work.

In the first set, the camera is just a couple of inches from the fence. The camera was in aperture priority mode, and the four shots were taken at f/2, f/4, f/8, and f/16. As you can see, at f/2, the fence blurs so much that it’s essentially invisible. At f/4, you can start to see the fence blurring parts of the image. At f/8 the fence is quite visible, and at f/16 it’s almost sharp.

Close f/2 Close f/4
Close f/8 Close f/16

This time, I’m standing about an arms length away from the fence.  At f/2, the fence is just a blurry grid.  At f/4 it starts to look like a fence, at f/8 it’s clearly a fence, and at f/16 it’s fairly sharp.

Medium f/2 Medium f/4
Medium f/8 Medium f/16

In the final set I’m standing about five feet away from the fence, and also at a slight angle.  At f/2 the fence is a blurry mess, at f/4 it starts to sharpen up, and at f/8 and f/16 it’s sharp enough to work as part of the image rather than being a flaw.

Far f/2 Far f/4
Far f/8 Far f/16

Conclusion: if there’s a fence in your way, figure out what you want to do about it and adjust accordingly.  If you want to make the fence disappear, get as close to it as you can, and open up your aperture as wide as possible.  If you want to use the fence as part of the image, back up a bit and stop down.

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Question: Shooting At The Zoo

I recently got an excellent reader question from TJ. It was such a great question that I thought it deserved its own entry, rather than being buried in comments.

Patti, I had a really frustrating experience last year when I attempted to take pictures at a zoo. Most of the occupants were birds and were housed behind 1″ grid wire. Frequently, they were shaded and I (and the camera) were not. Sometimes they were moving. Sometimes I had to shoot up into a tree and the sun was shining directly into the lens. Often, my camera wouldn’t focus, so I had to shift to manual focus. Sometimes, it wouldn’t even snap the picture when I was doing the focusing. I have a Nikon D70s. Might you give some tips on what I could’ve been doing wrong and how to shoot these types of pictures better?

IMG_2095TJ, that’s a really hard set of circumstances to work under, because you have so many things working against you. This is exactly the sort of situation that will confuse automatic modes on your camera, and require you to switch to manual settings in order to get good shots. I’m not sure I have a magic formula, but let me see if I can break the problem down and show you how I’d think about it.

First the fence. It’s going to do two things– get in the way of your shooting, and confuse your autofocus. Switching to manual focus is a great way to solve the latter problem, since you’re smarter than the camera is and you know to just ignore the fence. Once you’re in manual focus, you have two choices on how to deal with the fence– you can either stand back and use the fence as part of the composition, or you can put the lens up against the fence and shoot between the grids. Using a wide aperture will help the fence blur and fade out of the picture, especially if you’re close to it.

Medium f/8Here’s where things are going to get hairy and conflict with each other. You’re manually focusing on a moving target, so you sort of want to leave yourself some room for error– if you have a lot of depth-of-field, you’ll still have the bird in focus even if he starts moving. However, that’s in direct conflict with wanting to use a wider aperture to make the fence fade away. I would probably opt for using something like f/5.6 (I originally said f/11, but in retrospect I think that’s probably not the best answer) and then get as close to the fence as I could, but I’d play around with it and see what worked for that particular situation.

Once I found an aperture that I liked, I’d try to find the best shutter speed that worked with it. If I couldn’t get a fast enough shutter speed to capture the birds well, I’d increase the ISO until I did. If that still didn’t work, I’d open up the aperture until I found something that worked. There’s a pretty good chance that the camera’s metering will be confused here, so use it as a starting point rather than a final answer.

This is one of those places where digital has a huge advantage over film– you can try out the shot and see how it works. The birds aren’t going anywhere, so you can afford to spend a few minutes setting up a few shots and seeing what works, then making adjustments. Whenever I’m shooting under tricky lighting conditions, I always do a few test shots beforehand so that I can get my camera set up the way I want it.

Backlighting, especially shooting into the sun, is just hard. Don’t forget that your feet are an invaluable photographic tool. If you can’t get the shot because the sun is right in front of you, take a few steps. You’ll probably be able to find a better angle on your subject. If you’re close enough that you can use a flash to fill in some front light, that often works very well.

I haven’t used a Nikon dSLR, so I don’t know what will stop it from taking a shot. I know that my Canon will stomp its foot and get pouty if it can’t focus, but if I put it into manual focus it will shoot with the lens cap on in all exposure modes.

After I answered this question, I went out and took a few photos through a fence, to see what the fence looked like at different apertures and distances.  I’ll post them as a separate entry.

By the way, the bird photo at the top of this entry was taken at the St. Louis Zoo a few years ago, shortly after I got my first dSLR.  I can’t remember much about the photo, but it was taken through either glass or a fence in auto mode.  I included it partially because it matched the subject matter, but mostly to remind myself that just a little while ago all I really knew how to do was point the camera at something and hope for the best.

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