Here's a quite interesting "marketing" illustration by Panasonic about AF accuracy:
http://www.panasonic.net/avc/lumix/systemcamera/gms/g3/img/af/contrast_af_graph.gif
It matches my experience here.
Definitely interesting, but perhaps over-simplified. Did they do a similar comparison chart for AF accuracy of a moving target? <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt='  ' />
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
[quote name='popo' timestamp='1305200891' post='8253']
Definitely interesting, but perhaps over-simplified. Did they do a similar comparison chart for AF accuracy of a moving target? <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt=' ' />
[/quote]
This is the original page:
http://www.panasonic.net/avc/lumix/systemcamera/gms/g3/af.html
As far as tracking is concerned I wouldn't really call this hard data.
However, the Sony SLTs are "good" here already so there's no reason why the Gs should be any worse.
It's funny that they put the emphasis on f/1.4 without having such a lens in the line-up (yet).
[quote name='ThomasD' timestamp='1305208967' post='8257']
It's funny that they put the emphasis on f/1.4 without having such a lens in the line-up (yet).
[/quote]
You can use a Leica 25/1.4 via adapter.
[quote name='Klaus' timestamp='1305202605' post='8255']
As far as tracking is concerned I wouldn't really call this hard data.
However, the Sony SLTs are "good" here already so there's no reason why the Gs should be any worse.[/quote]
But the SLTs are phase AF like SLRs. I'm all for accurate AF, but the other side is speed and tracking accuracy before you can start to think about retiring SLRs. I'd love the Panasonic contrast AF speed even, but I'd rather have it in a Canon or Olympus body... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='  ' />
Like the old saying "use the right tool for the job". Panasonic contrast AF speed is excellent, but it is a long way from replacing a DSLR in all applications.
An interesting note on the Panasonic web page, they say the AF is faster as they are sampling faster. I wonder if that would simply scale to DSLRs also. I assume they work in live view/video mode, perhaps up to 60fps, but if the sensor were designed to work at higher framerates, that could help improve contrast AF speed on them too?
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
[quote name='popo' timestamp='1305218302' post='8267']
But the SLTs are phase AF like SLRs. I'm all for accurate AF, but the other side is speed and tracking accuracy before you can start to think about retiring SLRs. I'd love the Panasonic contrast AF speed even, but I'd rather have it in a Canon or Olympus body... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=' ' />
Like the old saying "use the right tool for the job". Panasonic contrast AF speed is excellent, but it is a long way from replacing a DSLR in all applications.
An interesting note on the Panasonic web page, they say the AF is faster as they are sampling faster. I wonder if that would simply scale to DSLRs also. I assume they work in live view/video mode, perhaps up to 60fps, but if the sensor were designed to work at higher framerates, that could help improve contrast AF speed on them too?
[/quote]
Yeah, you're right.
[quote name='popo' timestamp='1305218302' post='8267']
But the SLTs are phase AF like SLRs. I'm all for accurate AF, but the other side is speed and tracking accuracy before you can start to think about retiring SLRs. I'd love the Panasonic contrast AF speed even, but I'd rather have it in a Canon or Olympus body... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=' ' />
Like the old saying "use the right tool for the job". Panasonic contrast AF speed is excellent, but it is a long way from replacing a DSLR in all applications.
An interesting note on the Panasonic web page, they say the AF is faster as they are sampling faster. I wonder if that would simply scale to DSLRs also. I assume they work in live view/video mode, perhaps up to 60fps, but if the sensor were designed to work at higher framerates, that could help improve contrast AF speed on them too?
[/quote]
***edit, I completely misread your post, you were referring to contrast af mode on DSLR's, my apologies***
Others will correct me if I'm wrong, but how I understand it, there's no such thing as sampling rate in phase detection AF. It's rather a "one time measurement" of phase difference then translated to a defined amount of focusing lens movement. So I'm not really sure what more could be done here to gain a remarkable of magnitude of improvement.
It seems to me that moving to "final image" based analysis (e.g. based on actual imaging sensor feed, contrast AF) would allow to put a lot more intelligence in scene detection (including tracking) as processing power keeps rising.
Greetings,
S.
[quote name='Sylvain' timestamp='1305235828' post='8273']
Others will correct me if I'm wrong, but how I understand it, there's no such thing as sampling rate in phase detection AF. It's rather a "one time measurement" of phase difference then translated to a defined amount of focusing lens movement. So I'm not really sure what more could be done here to gain a remarkable of magnitude of improvement.
It seems to me that moving to "final image" based analysis (e.g. based on actual imaging sensor feed, contrast AF) would allow to put a lot more intelligence in scene detection (including tracking) as processing power keeps rising.
Greetings,
S.
[/quote]
Of course there is a sampling rate, the AF sensor samples all the time. Whether all those samples translate into AF movement commands is something different.
Besides that, PD AF is not a "one time measurement" affair, although that is a widespread belief on the interweb. PD AF still happens in different steps, even though the steps are not broken down into so many tiny ones like with CD AF.
You are correct in that a comparison of "sampling rate" makes no sense.
Tracking a subject moving from/to the camera will always be a problem with CD AF, as it does not see depth in any way. It can not tell if unsharpness is because a subject is in front or behind a subject.
Only integrating PD AF into the imaging sensor will give imaging sensor AF that capability. but then it again will be PD AF.
To clarify, yes, I was trying to say if DSLR contrast AF could be speeded up if they sample faster in a similar way to how Panasonic describe. I'm assuming the DSLR sampling rate will be at most that provided by the video modes, or up to 60fps typically.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
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