Auto focus with 5dMkii while filming??

OK...I went to a Canon seminar on DSLR video a couple of weeks ago and thought I saw the guy press the AF focus button while filming and the camera adjusted the focus. Not exactly "smooth" as I recall. I think the screen went dark momentarily, for example.
However, now I've been playing around with the camera for an hour and the AF-ON button doesn't seem to have any focus function at all once I start in the filming mode. Am I missing something or doing something wrong....or is my recollection of the Canon demonstration incorrect?

Having said this, I do realize that I will likely use manual focus for most of the shooting. Though it would be nice to have some sort of "auto" available for tweaking, etc. If possible!! Just trying to figure out what tools are available.

Thanks much!

Put it on mode and you can autofocus. It's slow as hell, but might work

Oh oh....I'm afraid I don't understand what mode that is!?
(Do you mean "face" mode? What if there is no face?)
Thanks for the prompt response!

the auto thing seems to do it but it is slow
I just do it by hand

rgrebby wrote in post #10557136
the auto thing seems to do it but it is slow
I just do it by hand

How does one do the auto thing? I can't seem to figure that part out....whenever I press the AF-ON, button, all I get is info on the screen rather than a focus box. And no auto focusing takes place at all....??

press AF-ON and it will auto focus, not sure if you can do it while ercording though.

rgrebby wrote in post #10558710
press AF-ON and it will auto focus, not sure if you can do it while ercording though.

Tried halfpressing the shutter button instead?

LSV wrote in post #10558727
Tried halfpressing the shutter button instead?

Did that...doesn't do anything.
Does that work for you? I'm wondering if I have to tweak a setting or two somewhere....

AF will work but as it uses a sensor array located behind the mirror the mirror will drop down causing a gap in the video.

You will still get audio recording but the in-camera audio will pick up the focussing motors and mirror slap.

TBH the only real use that I have found for AF is in pre-focussing to get "close to" prior to starting filming. Once the filming is started it's manual all the way.

BTW - where was the seminar you attended?

Nightstalker wrote in post #10559290
AF will work but as it uses a sensor array located behind the mirror the mirror will drop down causing a gap in the video.

You will still get audio recording but the in-camera audio will pick up the focussing motors and mirror slap.

TBH the only real use that I have found for AF is in pre-focussing to get "close to" prior to starting filming. Once the filming is started it's manual all the way.

BTW - where was the seminar you attended?

Thanks....I'm tending to get that impression. That is, forget about auto-focus altogether.
It's just that I kind of recall the Canon guy at the seminar demonstrating how to do it....??

The Canon seminar on DSLR was at Calumet Photo....in Oakbrook, Illinois. I think they offer it at various times at different locations.

you could always get one of those eye piece mount things, do they do them cheap on ebay?

You are suppose to hit the AF button before you start recording. It will focus and then once you start recording it will try to maintain that focus. It's definitely slow though. I've shot some impromptu vids of my daughter and it did ok.

main issue im having is keeping it still with the 85mm on shame it doesnt have some kind of internal IS...

Was interested in the Seminar because I think I took the same one just over 2 weeks ago but I was at Calumet in Liverpool, UK.

rgrebby wrote in post #10559716
main issue im having is keeping it still with the 85mm on shame it doesnt have some kind of internal IS...

Stick it on a tripod or look into a steadycam setup.

There are plenty of DIY Steadycam options if you search google.