HD video on D7000 focusing??

Michiyo-Fir · Mar 3, 2011

I shoot with a D7000 and I've rarely used the video and when I did, I put it on AF-F, full time autofocus, but I find that on AF-F every few seconds the camera becomes completely unfocused and pans for a long time to find the focus.

So I put it on manual focus but the problem I have is that I can't tell if the video is 100% focus. Is there an indicator somewhere to tell me when it's in focus?

Half the time I think it's in focus on the LCD, but when I get onto my computer I find that it's a bit off.

Most of the stuff I do is animals by the way. Not animals running or anything like that but they do move a little.

Any suggestions on what I can do?

reznap · Mar 3, 2011

Michiyo-Fir said:
I shoot with a D7000 and I've rarely used the video and when I did, I put it on AF-F, full time autofocus, but I find that on AF-F every few seconds the camera becomes completely unfocused and pans for a long time to find the focus.

Make sure you're using a single focus point and keeping it on your subject. It's the same as focusing in live-view.. it's autofocusing using contrast detection, not phase detection like when the mirror is up. Basically that boils down to: It's going to be slower.

Michiyo-Fir said:
So I put it on manual focus but the problem I have is that I can't tell if the video is 100% focus. Is there an indicator somewhere to tell me when it's in focus?

With the magic lantern hack for the Canon cameras they're starting to incorporate focus detection during movie recording, which appears as zebra stripes on the LCD screen. Hacking the firmware is kinda risky though and voids the warranty. I don't know if Nikon has something similar, a quick google didn't lead me to anything useful. I have heard that Nikon lets users modify firmware though, but I'm not sure if you'd be able to get what I described with the focus detection.

I guess it just takes practice. I've found it to be difficult recording movies.. really a DSLR isn't ideal for it. They make follow-focus rigs that cost big money but make it easier to focus and carry around. But yeah, practice is the only practical solution.

KmH · Mar 3, 2011

Yep, the more accurate and faster phase detection focus module cannot be used because the mirror is up.

Contrast focus has to hunt for re-focus whenever contrast is lost. Keeping it from doing that requires the videographer have a good understanding how contrast detection focus works.

As reznap alludes to, to use the video feature a dSLR has requires a number of somewhat costly attachments, like follow-focus, to make high quality video.

sierramister · Mar 3, 2011

Most videographers manually focus anyway, so why trust your SLR to focus for you? Get your hand up there! Besides, the noise is unbearable because the mic picks up all the focusing noise, so if you rely on AF, you should really get an external mic.