GH4 Doesn't Auto-Focus Worth #$@!

Dave Allen · June 30th, 2015, 07:01 PM

Noa, the reason for wanting peaking when using autofocus while filming is it is usually far easier to see in an extremely dynamic environment with middle aged eyes the dazzle of the focus peaking to confirm the autofocus is right than it is to visually see that the moving tiny subject looks in focus.

In a dynamic environment with the moving subjects ranging in size from of a large goliath beetle to a subject as small as the size of these letters in this sentence, and with the accompanying shallow depth of field at such high magnifications and with no time to set up a tripod, manual focus is rarely realistic and handheld is used. I know, all those things conspire against me, but with my old bulky 3CCD HDV cam, I regularly nailed it, with footage usable 90% of the time, but HDV is a dinosaur now. 4k footage acquisition offers opportunities in post for stabilization, digital zooms, reframing and slow digital pans.

Jim Michael · June 30th, 2015, 08:30 PM

So now you have a smaller circle of confusion and shallower depth of field. Very challenging. Can you push the diffraction envelope a little and crank up the light with a smaller f-stop? What does Online Depth of Field Calculator say your focus depth is at your current aperture? How does it compare with your old system?

Noa Put · July 1st, 2015, 12:37 AM

Quote:

Originally Posted by Dave Allen

Noa, the reason for wanting peaking when using autofocus while filming is it is usually far easier to see in an extremely dynamic environment with middle aged eyes the dazzle of the focus peaking to confirm the autofocus is right than it is to visually see that the moving tiny subject looks in focus.

Your best bet might be teh sony a6000 or the canon 70d with the macro lens if you don't want to break the bank because I have seen very good results from their autofocus capabilities, but if your requiremet is 4K I don't know what camera would be able to do what you expect from it.

Dave Allen · July 1st, 2015, 03:27 PM

Noa, that is why I am thinking of the new Sony A7RII, as it has 399 focus points on it sensor.

Noa Put · July 1st, 2015, 04:33 PM

Those 399 focus points are most likely used to take an image but I"m sure that will not apply for continuous autofocus while shooting video.

Dave Allen · July 1st, 2015, 08:18 PM

Sony does have a promo film out that seems to really promote the continuous autofocus capabilities of the new cam.

http://www.youtube.com/watch?v=5Ea5lKyWxGc#t=42

Ade Towell · July 2nd, 2015, 09:43 AM

samsung nx1 is 4k and apparently has very good af

June 30th, 2015, 07:01 PM	#16
Dave Allen Major Player Join Date: Apr 2008 Location: Boston Posts: 497	Re: GH4 Doesn't Auto-Focus Worth #$@! Noa, the reason for wanting peaking when using autofocus while filming is it is usually far easier to see in an extremely dynamic environment with middle aged eyes the dazzle of the focus peaking to confirm the autofocus is right than it is to visually see that the moving tiny subject looks in focus. In a dynamic environment with the moving subjects ranging in size from of a large goliath beetle to a subject as small as the size of these letters in this sentence, and with the accompanying shallow depth of field at such high magnifications and with no time to set up a tripod, manual focus is rarely realistic and handheld is used. I know, all those things conspire against me, but with my old bulky 3CCD HDV cam, I regularly nailed it, with footage usable 90% of the time, but HDV is a dinosaur now. 4k footage acquisition offers opportunities in post for stabilization, digital zooms, reframing and slow digital pans. __________________ Dave -

June 30th, 2015, 08:30 PM	#17
Jim Michael Major Player Join Date: Dec 2005 Posts: 895	Re: GH4 Doesn't Auto-Focus Worth #$@! So now you have a smaller circle of confusion and shallower depth of field. Very challenging. Can you push the diffraction envelope a little and crank up the light with a smaller f-stop? What does Online Depth of Field Calculator say your focus depth is at your current aperture? How does it compare with your old system?

July 1st, 2015, 03:27 PM	#19
Dave Allen Major Player Join Date: Apr 2008 Location: Boston Posts: 497	Re: GH4 Doesn't Auto-Focus Worth #$@! Noa, that is why I am thinking of the new Sony A7RII, as it has 399 focus points on it sensor. __________________ Dave -

July 1st, 2015, 04:33 PM	#20
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,510	Re: GH4 Doesn't Auto-Focus Worth #$@! Those 399 focus points are most likely used to take an image but I"m sure that will not apply for continuous autofocus while shooting video.

July 1st, 2015, 08:18 PM	#21
Dave Allen Major Player Join Date: Apr 2008 Location: Boston Posts: 497	Re: GH4 Doesn't Auto-Focus Worth #$@! Sony does have a promo film out that seems to really promote the continuous autofocus capabilities of the new cam. http://www.youtube.com/watch?v=5Ea5lKyWxGc#t=42 __________________ Dave -

July 2nd, 2015, 09:43 AM	#22
Ade Towell Regular Crew Join Date: Aug 2009 Location: nottingham, uk Posts: 54	Re: GH4 Doesn't Auto-Focus Worth #$@! samsung nx1 is 4k and apparently has very good af