05-13-2011, 09:24 AM
[quote name='PuxaVida' timestamp='1305269883' post='8285']
Agreed... Way too over-simplified... Measuring AF accuracy in a decent quantitative way and puting results on a graph (like these unbelievably nice looking curves) seems to be unrealistic to me. CD part might be OK because it's their system, and they have a specific way to measure it. But what about the counter part? Which PD AF, what kind of a scene is it, are there moving subjects etc...
Serkan
[/quote]
As far as PD AF is concerned you can simply try it yourself. Choose manual focusing, then check the focus -range- where the in-focus indicator is active. At the end of the day this is also the range which is considered to be Ok by the PD AF. It is the same focus check mechanism after all.
PD AF is also performed at max. aperture so it is vulnerable to focus shifts when stopping down (residual spherical aberration).
The Panasonic illustration is not scientifically correct though because the various PD AF have all different characteristics, of course. From a qualitative point of view it is absolutely valid though.
Agreed... Way too over-simplified... Measuring AF accuracy in a decent quantitative way and puting results on a graph (like these unbelievably nice looking curves) seems to be unrealistic to me. CD part might be OK because it's their system, and they have a specific way to measure it. But what about the counter part? Which PD AF, what kind of a scene is it, are there moving subjects etc...
Serkan
[/quote]
As far as PD AF is concerned you can simply try it yourself. Choose manual focusing, then check the focus -range- where the in-focus indicator is active. At the end of the day this is also the range which is considered to be Ok by the PD AF. It is the same focus check mechanism after all.
PD AF is also performed at max. aperture so it is vulnerable to focus shifts when stopping down (residual spherical aberration).
The Panasonic illustration is not scientifically correct though because the various PD AF have all different characteristics, of course. From a qualitative point of view it is absolutely valid though.