Although I enjoy working with multiple off-camera flash units, I do most of my shooting in available light, and low light at that. I’ve always bought the fastest lenses I could afford, and I’m often forced to use them at maximum aperture. Shot wide-open, a fast lens (f/1.4, f/1.8, even f/2.8) produces very narrow depth of field, which means that focus must be very accurate or the subject will not be sharp. Moreover, because I shoot at high ISOs (1600, 3200, 6400), any lack of focus is exacerbated by graininess in the image. On top of that, the D7000’s higher resolution also exaggerates focus errors.
Last week I learned a little bit about manufacturing variance, because I shot a rehearsal of Nordhoff High School’s Romeo and Juliet with two identical camera bodies with identical settings, but half of my pictures were not sharp.
I was so upset to find myself with 500 out of focus images that I sent the camera back to Amazon for an exchange. When the replacement camera arrived, I did some tests and found the focus point to be inconsistent with different lenses. So I consulted Thom Hogan, whose guide books are the first accessory I buy for any new camera, to find out whether I had a defective camera or whether, in his experience, this was a normal manufacturing variation. He thought the latter, so I spent a morning seriously studying a Nikon feature I’d only played with before.
Nikon’s higher-end models include a menu option called AF Fine Tune. It allows you to move the focus point forward or backward for each lens, and it remembers the value. Fine-tuning autofocus truly challenges the patience of a lazy, disorganized, impatient photographer like myself. It requires an extremely methodical use of tripod, focusing charts, and note-taking. I had to make adjustments that seemed rather severe to me, but it worked. And once it’s done, it’s done, and provides tremendous peace of mind that I can grab any camera and lens combination in my bag and produce a sharp picture. And if I don’t get a sharp image, it’s not the camera’s fault.