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View Full Version : Kit lens breathing?



TrueIndigo
06-24-2009, 01:42 PM
I was going through some early footage I had shot. Most of my footage so far has been handheld using a pistolgrip, but this particular test was a static shot on a tripod. As the subject moved closer and further to the camera, the kit lens (in auto focus continuous mode) slightly changed focus accordingly. As I was stepping through the footage frame-by-frame (it wasn't the 1280 x 720 x 50 fps camera material but an uncompressed 25 fps avi copy, though that shouldn't make any difference), I noticed something happen several times. When the kit lens changed focus, the image size suddenly changed slightly. This to me looked like classic lens "breathing". Anyone else see this? I only noticed it because the footage was a static tripod shot.

EDIT: sorry, I didn't word this post well -- of course (no panic) I don't mean the frame size changed, but the field of view changed slightly when the focus changed. I expect this to happen with still camera lenses not designed for filming, but the kit lens was supposed to be ready for video (and supposedly doubled the cost of the camera), so I was a bit disappointed. Just wondering if anyone else has seen this...

Ben_B
06-24-2009, 09:09 PM
I have seen it in sample footage, I think it's always there in zooms and pretty much non-perceivable because it doesn't change direction, but when doing autofocusing it's kind of focusing back and forth trying to find the middle ground and you do notice the oscillation in FOV because it is oscillating, not going from one place to another. Try a major rack focus manual, I bet you won't notice it even if it's there.