Thursday, February 24, 2011

D7000 video: focusing noise comparison

Video's pretty tough for me. Some of my coworkers are talented at it, but I always absent-mindedly swivel the camera vertical, or say something, or God forbid, laugh, which always sounds terrible right in the microphone.
But. All other matters aside, video is obviously the way of the future in DSLRs, and is one of the features most earnestly reviewed when a new one comes out.
The D7000 shoots video, and it has full-time autofocus while in video mode. Having watched a lot of videos I know that this is not something you want to use often. It's going to look unprofessional, and it's going to be noisy. And the camera's definitely going to be slower to autofocus when it's in live view or video mode, since it has to use a different and less-efficient method while the shutter's open than it does when in the normal mode. But it's good that it has the possibility-- if you're just trying to document something, you don't have time to manually focus. And you can always edit out the part where the camera's hunting for focus later.
All that aside, though, how loud is it? I know that you can get an external mike for the D7000, so all of this is irrelevant if you're serious about being professional. But it's worth comparing, so you can take it into account while you're learning how to use the thing.
What am I comparing? I'm comparing an AF lens, with no motor, to an AF-S lens, which has its own motor. The difference is the camera's in-body focus motor. Guess what? It's a big difference.

Here is a brooch of my grandmother's, a little gold rosebud. I took a pretty picture of it first, playing with a Sigma macro lens (it's their 50mm f/2.8, which is a wonderfully-affordable little number). This lens does not have a built-in motor, but is AF.
Still shot:

Then I switched to manual focus, cranked the focus way out, put it back in auto, turned the video on, and recorded while pressing the shutter button down to focus. I was doing this in a room with other people; when I played the video back on the camera, everyone turned around to ask what that awful noise was. It's way louder on playback than it was while the camera was operating. Why? Because the focus motor is right there, and the microphone right there. So it chatters and clunks and generally sounds astoundingly loud.

Then I switched back to the D7000's kit lens, which is the Nikkor 18-105mm f/3.5-5.6. This is an AF-S lens, meaning it has its own motor built in. It has a characteristic squeaking sound while it focuses. Turns out that's way less offensive in video. I did the same thing-- switched to manual, cranked the focus way out, put it back in auto, started recording and pressed the button down to focus.

So there you have it. If you've got to rely on the autofocus during video shooting, be advised that AF-S lenses will still make noise, but it's significantly less noise than AF lenses will, particularly non-Nikkor ones.

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