autofocus during video recording - but NOT continuous. Does this exist?

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dv416

Well-known member
Is there any DSLR that allows you to half-press the shutter during video recording and have the camera catch focus at that particular moment?

NOT continuous auto focus. Just the half press, catch focus, during video recording. Does that exist for any camera?

Also, what is that mode technically called in a video context? I'm a manual focus guy, and I feel like an idiot trying to describe it.
 
Pretty sure the OP is asking about doing this during a recording session. The half press shutter works as long you aren't actively recording anything. Meanwhile, the Panasonic Gh2 has what you are describing- There is AFC for continous and AFS which will focus-on-demand. I believe others, such as the Sony Nex series do as well. But not the popular Canons described above. The next generation of Canon lenses and new bodies are rumored to support AF during video and will likely offer this (t4i is supposed to support it with the proper lenses already I think).
 
M. Gilden said:
Pretty sure the OP is asking about doing this during a recording session. The half press shutter works as long you aren't actively recording anything. Meanwhile, the Panasonic Gh2 has what you are describing- There is AFC for continous and AFS which will focus-on-demand. I believe others, such as the Sony Nex series do as well. But not the popular Canons described above. The next generation of Canon lenses and new bodies are rumored to support AF during video and will likely offer this (t4i is supposed to support it with the proper lenses already I think).
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Actually, Canon DSLRs can do this, even during recording. There is an exposure change during focusing, it's slow, and I wouldn't recommend using it, but it works.

There is a menu item to disable this functionality during recording, and any serious user of the video mode would disable it - perhaps that's why you are confused.
 
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dv416 said:
Is there any DSLR that allows you to half-press the shutter during video recording and have the camera catch focus at that particular moment?

NOT continuous auto focus. Just the half press, catch focus, during video recording. Does that exist for any camera?

Also, what is that mode technically called in a video context? I'm a manual focus guy, and I feel like an idiot trying to describe it.
Click to expand...

M. Gilden said:
the Panasonic Gh2 has what you are describing- There is AFC for continous and AFS which will focus-on-demand.

The next generation of Canon lenses and new bodies are rumored to support AF during video and will likely offer this (t4i is supposed to support it with the proper lenses already I think).
Click to expand...

The Canon T4i kind of "plays catch up" with what the Panasonic GH2 can do in this area. There is a better way than using the "half press" on the shutter button. With touchscreen enabled allowing "touch focus" (but not "touch focus and shutter") all you need to do is "touch" the subject you need to focus on even while recording and it will do it, refocusing if necessary.

This works so well I use it for "rack" focus. It's neat, simple, quick and effective.

I believe the Canon T4i will do this as well.

Continuous autofocus can be more than problematic. If your background elements have any degree of focusable contrast, in tests I've run with the GH2 I often get a "pumping" action where the focus goes continually back and forth between subject and background. I've heard the same thing concerning the T4i and the new lenses developed for continuous autofocus.

However, on the GH2, if you have it set for Single Autofocus and Face Detect, you can start your recording then "touch focus" on the subject's face and as long as the face is kept towards the camera the camera will attempt to "follow focus" on that face.

I sometimes use this when I'm working alone and have to get out in front of the camera.
 
Bruce Foreman said:
you can start your recording then "touch focus" on the subject's face and as long as the face is kept towards the camera the camera will attempt to "follow focus" on that face
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The Canon T4i also has face tracking via touch focus.

It also works for static objects when you are moving. For example, touch a billboard and have that be the subject. Then as you walk toward it, or pan across it, or walk diagonally so that it gets bigger/smaller/moves position in frame, etc. the camera will keep focus locked on that. Pretty cool way to use it.

I really love the T4i. I think you have to use it to see how it can change your process, like pulling focus as mentioned above.

It also has much better still auto focus than the T3i. It has 9 cross-type focus points, the same as the 60D, with a center precuisoon point.

The T3i has only 1 cross type in the centere. The T4i is much better in low light or low contrast situations. The 18-135 STM is also quite quick to focus and lock in still image mode. Great value camera!
 
nothing said:
Actually, Canon DSLRs can do this, even during recording. There is an exposure change during focusing, it's slow, and I wouldn't recommend using it, but it works.

There is a menu item to disable this functionality during recording, and any serious user of the video mode would disable it - perhaps that's why you are confused.
Click to expand...

True, I forgot about that option being disabled.
But since the video is totally unusable for that brief moment of focus (exposure change, vibration/noise, etc) I wouldn't consider it an option either way.
 
I just did some quick tests on "touch" focus on one of my GH2's and there is no exposure change, no visible effect other than a change in focus.

Very smooth.

I assume it is much the same with the Canon T4i.
 
Bruce Foreman said:
I just did some quick tests on "touch" focus on one of my GH2's and there is no exposure change, no visible effect other than a change in focus.

Very smooth.

I assume it is much the same with the Canon T4i.
Click to expand...

Right, that's why I consider this a selling feature on the GH2, because Canon's implementation of it wasn't usable. And this will work with just about any Lumix lens that I've seen (although some are better than others).
The T4i should be similar as long as you have one of the new "video" lenses that advertise being able to do this. The classic EOS lenses folks around here like to recommend and use won't be any good at that.
 
AF While filming is slow, but very accurate. The exposure flickers and the focus hunts quite a bit but when it locks on it is always spot on in my experience. If you have several cameras running at the same time (eg a wedding of concert) it is a great way to make sure your focus is correct without having to stop recording and lose synchronisation with the other cameras. Of course, in this kind of situation you are able to cut to out the focus hunting and switch to another camera. In single camera applications it is much less effective.
 
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