01-05-2011, 01:13 PM
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
If the vignetting is quantified by finding the point in the gray scale (of known density, positioned in the center of the image) which matches the luminosity of the corner of the image studied, then the resulting EV values are independent of the post-processing used in the camera and remain unaffected by any uniformly applied post-processing.[/quote]
I think you're suggesting that they don't use a digital sensor for measuring vignetting?
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
Increase contrast? The vignetting gets stronger in visual appearance ...
[/quote]
That's what PZ says
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
Zeiss reports vignetting as a...
[/quote]
I didn't know Zeiss discovered vignetting ;D
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
This procedure is a little harder to do, but it produces values that are immediately meaningful and comparable across sites and camera systems, when the experiment is correctly carried out.
[/quote]
Nopes... you can't compare across camera systems because of things like the differences in sensor response curves. You can't directly compare across different sites because not everyone follows the exact same process, although each site might follow a process that is acceptable.
GTW
If the vignetting is quantified by finding the point in the gray scale (of known density, positioned in the center of the image) which matches the luminosity of the corner of the image studied, then the resulting EV values are independent of the post-processing used in the camera and remain unaffected by any uniformly applied post-processing.[/quote]
I think you're suggesting that they don't use a digital sensor for measuring vignetting?
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
Increase contrast? The vignetting gets stronger in visual appearance ...
[/quote]
That's what PZ says
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
Zeiss reports vignetting as a...
[/quote]
I didn't know Zeiss discovered vignetting ;D
[quote name='ilkka_nissila' timestamp='1293576724' post='5255']
This procedure is a little harder to do, but it produces values that are immediately meaningful and comparable across sites and camera systems, when the experiment is correctly carried out.
[/quote]
Nopes... you can't compare across camera systems because of things like the differences in sensor response curves. You can't directly compare across different sites because not everyone follows the exact same process, although each site might follow a process that is acceptable.
GTW