Monday, July 23, 2012
How To Focus Through Fences
I was asked recently if I could write a tutorial on how to focus through chain link and other wire type fences. In other words, how do you get the camera to focus on the subject on the other side of a fence rather than the fence itself. The example given was like at a zoo where you want to photograph an animal, but the camera keeps focusing on the fence. Much of this will apply to DSLR's and, as always, it will depend on your camera and its capabilities. Some of the tips will work with point and shoots, but not all of them. Other factors will come into play like your distance from the fence, the subject's distance from the fence, etc.
The best way to gain control over your camera's focus is to use manual focusing. Many people who own a DSLR have never focused manually. Because cameras are capable of being used in full auto mode, we often don't think to take control away from the camera. Many lenses have a switch on them that allow you to choose auto focus or manual. You may need to refer to your owner's manual to find out how to set this for your equipment. Focusing manually is not as daunting as it may seem. Granted, if you've never done it, there is a bit of a learning curve, but it's not that bad. By focusing manually, you can avoid the fence problem and focus directly on the subject on the other side. This is easier when the subject is still, but can be done on moving animals. At zoos, many animals will pace or wander the same path over and over. If you're having trouble manually focusing on a moving animal, the way around that is to pre-focus on a point where you know the animal will walk and take the shot when it comes into that spot. Manually focusing on motionless animals is easy and is the best way to overcome the tendency for the camera to focus on the fence.
DSLR cameras have a certain number of focus points which are usually indicated by squares on the focus screen when you look through the viewfinder. The number of focus points varies from brand to brand and model to model. As far as I know, all DSLR's allow you to choose either all focus points or a single focus point. How that is achieved also depends on the particular camera. That's where you need to refer to your owner's manual.
If manual focusing is not something you feel you can do, you can set your auto focus point to the single center point and turn off the others. You can then aim the center point through a hole in the fence and onto the subject. Your distance from the fence is important for this. The closer you are, the easier it is to do. If you are too far from the fence, the opening may be too small for this to work. This is a common problem at zoos where there is a fence around the animals and other barriers beyond that to keep people back.
Having all of the focus points activated is good for general photography, but I rarely use my camera that way. The majority of the time, I use just the center point. I have my camera set up so I can change the focus point just by using the thumb pad on the back of the camera. This allows me to change the point even during shooting to adjust as the situation dictates. When all of the focus points are active, the camera will inevitably lock on the fence rather than the animal. Knowing how to set a single point will allow you to work around that.
Manual focus and setting a single focus point are the two options for keeping the camera from locking on a fence. Because it's so closely related to what I'm talking about, I also want to include some tips on how to reduce the presence of fences in photos.
This assumes you can get right up next to the fence. By putting your lens against an opening in the fence, it will reduce and sometimes eliminate the fence from the shot. Your lens also plays a part in this. A longer or telephoto lens won't show as much fence as a wide angle lens will. Even with a long lens, there may still be some "shadowing" in the photo. You may find, though, that you can get an acceptable shot just by sticking your camera right up to an opening.
Using a large aperture (small f number) will create a shallow depth of field and blur out the fence. This works best when there is some distance between the fence and the subject you're shooting. If the animal is close to the fence, the fence will be more prominent, too. The best way to set a specific f stop is to shoot in Aperture Priority (AV) mode or in manual. Leaving your camera on the "green square" or full auto will make this difficult since the camera will choose an aperture based on what it thinks is needed for the correct exposure.
Make The Fence Part Of The Shot
If all else fails, you can try incorporating the fence into your shot. If an animal is up against the fence, you could get a tight shot of an eye looking through an opening. If it's an animal hanging onto the fence, you could again get a tight shot and use that in the photo. This is where creativity and composition come into play. These kinds of fences usually aren't appealing for photographs, but with some imagination, you can compose an interesting shot.
Chain link and other wire fences are difficult to work around and zoos, in particular, are designed for our safety and that of the animals, not so much for photography. Obviously, it would be nice to avoid the fence altogether, but the point of this tutorial is to provide some tips when avoiding fences isn't possible. I am not an expert on the subject and I'm flattered I was asked to discuss it. These are things I've learned and have done myself. Sometimes the end result is what I wanted and sometimes not. Most of this you probably already know, but if there's anything here that helps, then I've accomplished what I wanted to do.
If you have a tip that has worked for you or there's something I haven't covered, feel free to share it in the comments. I certainly don't know everything and learning from others is part of the process of becoming a better photographer.