Low budget autofocus in HD? at DVinfo.net

Michael Wisniewski · January 23rd, 2006, 07:54 PM

Do you think, under optimal conditions that the autofocus in most HD/V camcorders is good enough to achieve pin sharp focus in HD/V?

The reason I ask is, it sounds like it would be very easy to create the optimal conditions for the autofocus system, by using something simple, like a piece of paper with black vertical lines.

By pre-focusing on the paper, I could avoid just relying on the LCD and also avoid having to rent & be tethered to an HD monitor.

In low light situations, I could use a flashlight or something to temporarily illuminate the paper before pre-focusing.

Any thoughts?

Boyd Ostroff · January 23rd, 2006, 08:06 PM

Funny, I used a trick just like this awhile ago when shooting some digital still photos with my Nikon Coolpix camera in low light.

I haven't shot enough with the autofocus on my Z1 to really answer this question. However, the LCD panel (while far from HD resolution) is really not bad on the Sony. Using the expanded focus mode I think you can get pretty accurate in manual mode. And for that matter, by racking in and out of focus even in normal mode I'm having pretty good luck focusing the Z1.

But I suspect the peaking function gives a fair idea of what the autofocus is capable of. In low contrast/dark conditions the peaking outlines often won't appear at all. I'd assume that mean autofocus would also have a hard time in such a scene.

Victor Burdiladze · January 23rd, 2006, 10:02 PM

If the shot is not very complicated, I guess you could get away without monitor; if the shot requires lot of movements and your objective is clear picture (such as in film-making or similar case,) I would rent a non-LCD monitor, or even use a home TV for more accurate result.

Tom Roper · January 23rd, 2006, 10:08 PM

The Z1U achieves pin sharp focus with its passive auto-focus even in many sub-optimal conditions. Most always it's inane at getting sharp auto-focus on the subject. It gets fooled occasionally when shooting into the sun, flare reflects back on the skylight filter causing a sharp spot reflection on the filter that causes the focus to go near-sighted.

I just about always put my complete trust in the auto-focus. It's right way more often than wrong, but you can clearly spot trouble at any time by checking the LCD screen or the viewfinder.

Of course, I'm not a movie maker. Anyone doing that is making deliberate decisions about what's to be in focus and what's not, so manual is the rule when shooting conditions are controlled.

But if you're bird watching, the last thing you want is for your subject to fly out of the frame while you're still trying to manually focus.

Victor Burdiladze · January 23rd, 2006, 10:42 PM

The point I tried to make was that I never trust LCD monitors (even expensive ones,) and I have strong reasons for that. One could easily connect the camera to a home TV and get more precise reding.
As far as manual lens and film-makig, I was referring to a case, when one can't afford a camera with manual lenses.

David Kennett · January 25th, 2006, 04:12 PM

This discussion - and complaints, goes back to the intro of HD1-HD10. Those little lo-res monitors just don't work for focusing. I always thought that the AF on my HD10 was one of its strong points. The consensus at that time was "let the AF do its thing - then turn it off"

January 23rd, 2006, 07:54 PM	#1
Michael Wisniewski Wrangler Join Date: Jul 2002 Location: Makati, Metro Manila Posts: 2,706 Images: 32	Low budget autofocus in HD? Do you think, under optimal conditions that the autofocus in most HD/V camcorders is good enough to achieve pin sharp focus in HD/V? The reason I ask is, it sounds like it would be very easy to create the optimal conditions for the autofocus system, by using something simple, like a piece of paper with black vertical lines. By pre-focusing on the paper, I could avoid just relying on the LCD and also avoid having to rent & be tethered to an HD monitor. In low light situations, I could use a flashlight or something to temporarily illuminate the paper before pre-focusing. Any thoughts? __________________ "Ultimately, the most extraordinary thing, in a frame, is a human being." - Martin Scorsese

January 23rd, 2006, 10:02 PM	#3
Victor Burdiladze Regular Crew Join Date: Jan 2006 Location: NY, US Posts: 102	Depends on shooting... If the shot is not very complicated, I guess you could get away without monitor; if the shot requires lot of movements and your objective is clear picture (such as in film-making or similar case,) I would rent a non-LCD monitor, or even use a home TV for more accurate result.

January 23rd, 2006, 10:42 PM	#5
Victor Burdiladze Regular Crew Join Date: Jan 2006 Location: NY, US Posts: 102	Lcd? The point I tried to make was that I never trust LCD monitors (even expensive ones,) and I have strong reasons for that. One could easily connect the camera to a home TV and get more precise reding. As far as manual lens and film-makig, I was referring to a case, when one can't afford a camera with manual lenses.

January 25th, 2006, 04:12 PM	#6
David Kennett Major Player Join Date: Jul 2003 Location: North Ridgeville, Ohio Posts: 407	This discussion - and complaints, goes back to the intro of HD1-HD10. Those little lo-res monitors just don't work for focusing. I always thought that the AF on my HD10 was one of its strong points. The consensus at that time was "let the AF do its thing - then turn it off" __________________ Dave

January 23rd, 2006, 08:06 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Funny, I used a trick just like this awhile ago when shooting some digital still photos with my Nikon Coolpix camera in low light. I haven't shot enough with the autofocus on my Z1 to really answer this question. However, the LCD panel (while far from HD resolution) is really not bad on the Sony. Using the expanded focus mode I think you can get pretty accurate in manual mode. And for that matter, by racking in and out of focus even in normal mode I'm having pretty good luck focusing the Z1. But I suspect the peaking function gives a fair idea of what the autofocus is capable of. In low contrast/dark conditions the peaking outlines often won't appear at all. I'd assume that mean autofocus would also have a hard time in such a scene.

January 23rd, 2006, 10:08 PM	#4
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	The Z1U achieves pin sharp focus with its passive auto-focus even in many sub-optimal conditions. Most always it's inane at getting sharp auto-focus on the subject. It gets fooled occasionally when shooting into the sun, flare reflects back on the skylight filter causing a sharp spot reflection on the filter that causes the focus to go near-sighted. I just about always put my complete trust in the auto-focus. It's right way more often than wrong, but you can clearly spot trouble at any time by checking the LCD screen or the viewfinder. Of course, I'm not a movie maker. Anyone doing that is making deliberate decisions about what's to be in focus and what's not, so manual is the rule when shooting conditions are controlled. But if you're bird watching, the last thing you want is for your subject to fly out of the frame while you're still trying to manually focus.