When Autofocus Goes Bad

[It’s been a while since I updated Stop Shooting Auto! Too long, in fact. It’s time for me to get back to work, starting now.]

Thus far I’ve written a lot about the things that go into exposure– aperture, shutter speed, ISO. By now you should know a lot about how these things work, what your camera does automatically, and ways that you can be smarter than your camera. If you’re not comfortable with these things yet, go back through the exposure lessons and brush up on the things you’re missing. In particular, at this point you want to have a good handle on aperture and depth of field.

Exposure isn’t the only thing that your camera does automatically though. In almost all circumstances, your camera will also automatically focus for you. This is often a good and wonderful thing, since it makes your life easier, but sometimes the camera gets autofocus wrong. Let’s look at an example.

This evening I decided to set up the Stop Shooting Auto! Bear Portrait Studio and take some shots. Shooting bears is great for practicing your photographic skills because they’re eminently patient with you and won’t squirm around, fall asleep, or wander off to grab a beer from the ‘fridge.

The setup for the bear portrait studio is pretty straightforward. There’s an extra super ugly backdrop, which in this case is a really tacky sheet hanging from a backdrop stand. In front of that is a bear sitting in a chair. I have a few cheap incandescent lights set up, with two pointed at the backdrop and one on the bear. Finally, the camera is mounted on a tripod. For this example, the camera’s sensor is just under eight feet away from the backdrop. The bear’s eyes are 51 inches from the backdrop. The bear has quite the schnozz on him, as the tip of his nose is four inches in front of his eyes.

(My ethical standards require me to make the following disclaimer: Using a zebra print sheet for a backdrop is a profoundly bad idea, and you shouldn’t do that. Doing so may cause permanent damage to your retinas, or your psyche. Sometimes I think my purpose in life is to serve as a warning for others.)

I’m shooting with a Canon 5D Mark II, and a 50mm f/1.8 lens at f/4.

So, with this setup I took a portrait. Something went horribly wrong, though– the image sucks. Can you guess what the problem was? Click on the image if you want to see larger versions of it.