How can I achieve AUTO FOCUS to read the center of the frame? at DVinfo.net

Gustavo Godinho · September 29th, 2006, 07:50 AM

I thought Z1 had 2 serious flaws when using some automatic functions. The first one I fixed: the auto iris never exposed well IMO. If I had a man in the center of the frame with a clear sky behind him, his face ALWAYS looked underexposed. I discovered OVERRIDE function 2 minutes ago.

But there´s another problem left: auto focus. I didn´t understand yet where in the frame he´s reading. Is there a way to achieve some kind of CENTER OF THE FRAME reading, and not this SMART READING I think Sony achieved?

Robert Young · September 29th, 2006, 05:13 PM

Autofocus is a mixed blessing.
The most bulletproof technique for me to get good focus with no drift, is to set the focus to manual, zoom in on the subject, push and hold the "autofocus" button till focus is sharp, release the button, recompose the frame and shoot.

Gints Klimanis · September 30th, 2006, 02:02 AM

I can't wait until camcorders use the autofocus technology that's available in even the most basic DSLRs. I would even pay for an upgrade "module" that would be as good as that on the Nikon DSLR, though I understand that due to the continuous nature of video, focusing is different. I'd even go for focus functionality *before* the shot, when the lens can be set to a wide aperture. I'm still seeing lots of video in which that backwall is in focus while the subject is not. I call that the Point&Shoot focus, as that problem plagues most of the consumer digital cameras.

Gareth Watkins · September 30th, 2006, 03:02 AM

Hi there

<I thought Z1 had 2 serious flaws when using some automatic functions. The first one I fixed: the auto iris never exposed well IMO.>

Personally I find the manual settings on the Z1 a joy to use... the iris is well placed for quick and precise exposure... Using the zebras makes this easy and accurate, with this camera you should neve need auto exposure.
The problem with all auto exposure is that the minute you get a brighter or darker subject in a significant part of your frame you see the iris compensating... This is the No1 reason why I'd never use auto exposure.

<Autofocus is a mixed blessing. >

Agree totally Re auto focus... again as with exposure, it can't know what you want sharp in the frame, and wanders off focus so often, I rarely use it ... If I do it as an aid or in situations where things are moving fast, or I don't have the time to use the zoom in method to get accurate focus... Even then in fast situations one is probably better off stopping down a bit, shooting at wide angle focused at say 2 or 3 metres.
It works ok on the wide angle settings but the minute you start shooting tight at wide aperture it's perfrmance is quite mediocre... the manual and push auto functions would be my choice for 90% of shooting situations.
In fact I think the difficulty to accurately focus manually is the biggest flaw in what is otherwise an excellent camera. With either the LCD or the Viewfinder I find it hard to see when subjects, especially faces are really sharp...

But I've certainly found that using the camera all manual gives you better results..

regards

Gareth

Tom Hardwick · September 30th, 2006, 10:39 AM

Got to agree with Gareth's thoughts on manual exposure. Spot on - and as he says, a joy to use that beautifully damped, and invisible on screen, and easy to get to, iris wheel.

But the Z1 has a neat trick (menu turn-on) of having focus assist. Say the camera focuses on the brick wall rather than the talent in front of it. In auto focus you can give the focus ring a quick twist in the 'nearer' direction and the Z1 will hunt for something closer (ie the talent) and lock onto that.

tom.

Robert Young · October 1st, 2006, 03:18 PM

Sony's focus assist is a clever way to deal with the problem. I tend to have the same difficulty Gareth refers to: It looks O.K. when I'm shooting, but watching the footage later on an HD monitor I can see the problems.
I've finally resigned myself to a short checklist before pulling the trigger, and one of the items is... duh!!.. focus the camera.
I do a lot of what I imagined was "run n' gun" - gotta use auto everything, but I'm finding that forcing a little discipline on myself is proving to be less time consuming than I feared, is almost becoming second nature, and has really, really cut down on the stupid mistakes (Oh, jeez.. WB was set for INDOOR???).
HDV seems to be quite a bit less forgiving than DV ever was.

September 29th, 2006, 07:50 AM	#1
Gustavo Godinho Regular Crew Join Date: Feb 2004 Location: Belém - Pa - Brazil Posts: 130	How can I achieve AUTO FOCUS to read the center of the frame? I thought Z1 had 2 serious flaws when using some automatic functions. The first one I fixed: the auto iris never exposed well IMO. If I had a man in the center of the frame with a clear sky behind him, his face ALWAYS looked underexposed. I discovered OVERRIDE function 2 minutes ago. But there´s another problem left: auto focus. I didn´t understand yet where in the frame he´s reading. Is there a way to achieve some kind of CENTER OF THE FRAME reading, and not this SMART READING I think Sony achieved? __________________ lml

September 29th, 2006, 05:13 PM	#2
Robert Young Trustee Join Date: Mar 2005 Location: Coronado Island Posts: 1,472	Autofocus is a mixed blessing. The most bulletproof technique for me to get good focus with no drift, is to set the focus to manual, zoom in on the subject, push and hold the "autofocus" button till focus is sharp, release the button, recompose the frame and shoot.

September 30th, 2006, 02:02 AM	#3
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	I can't wait until camcorders use the autofocus technology that's available in even the most basic DSLRs. I would even pay for an upgrade "module" that would be as good as that on the Nikon DSLR, though I understand that due to the continuous nature of video, focusing is different. I'd even go for focus functionality before the shot, when the lens can be set to a wide aperture. I'm still seeing lots of video in which that backwall is in focus while the subject is not. I call that the Point&Shoot focus, as that problem plagues most of the consumer digital cameras.

September 30th, 2006, 03:02 AM	#4
Gareth Watkins Major Player Join Date: Feb 2004 Location: France Posts: 578	Hi there <I thought Z1 had 2 serious flaws when using some automatic functions. The first one I fixed: the auto iris never exposed well IMO.> Personally I find the manual settings on the Z1 a joy to use... the iris is well placed for quick and precise exposure... Using the zebras makes this easy and accurate, with this camera you should neve need auto exposure. The problem with all auto exposure is that the minute you get a brighter or darker subject in a significant part of your frame you see the iris compensating... This is the No1 reason why I'd never use auto exposure. <Autofocus is a mixed blessing. > Agree totally Re auto focus... again as with exposure, it can't know what you want sharp in the frame, and wanders off focus so often, I rarely use it ... If I do it as an aid or in situations where things are moving fast, or I don't have the time to use the zoom in method to get accurate focus... Even then in fast situations one is probably better off stopping down a bit, shooting at wide angle focused at say 2 or 3 metres. It works ok on the wide angle settings but the minute you start shooting tight at wide aperture it's perfrmance is quite mediocre... the manual and push auto functions would be my choice for 90% of shooting situations. In fact I think the difficulty to accurately focus manually is the biggest flaw in what is otherwise an excellent camera. With either the LCD or the Viewfinder I find it hard to see when subjects, especially faces are really sharp... But I've certainly found that using the camera all manual gives you better results.. regards Gareth

September 30th, 2006, 10:39 AM	#5
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Got to agree with Gareth's thoughts on manual exposure. Spot on - and as he says, a joy to use that beautifully damped, and invisible on screen, and easy to get to, iris wheel. But the Z1 has a neat trick (menu turn-on) of having focus assist. Say the camera focuses on the brick wall rather than the talent in front of it. In auto focus you can give the focus ring a quick twist in the 'nearer' direction and the Z1 will hunt for something closer (ie the talent) and lock onto that. tom.

October 1st, 2006, 03:18 PM	#6
Robert Young Trustee Join Date: Mar 2005 Location: Coronado Island Posts: 1,472	Sony's focus assist is a clever way to deal with the problem. I tend to have the same difficulty Gareth refers to: It looks O.K. when I'm shooting, but watching the footage later on an HD monitor I can see the problems. I've finally resigned myself to a short checklist before pulling the trigger, and one of the items is... duh!!.. focus the camera. I do a lot of what I imagined was "run n' gun" - gotta use auto everything, but I'm finding that forcing a little discipline on myself is proving to be less time consuming than I feared, is almost becoming second nature, and has really, really cut down on the stupid mistakes (Oh, jeez.. WB was set for INDOOR???). HDV seems to be quite a bit less forgiving than DV ever was.