05-19-2012, 10:24 AM
[quote name='DavidBM' timestamp='1337394188' post='18292']
Hi Wim
I'm not sure that the fact that PF diminishes with stopping down necessarily indicates there is a lens involvement directly.
As you stop down, I think the angle of the light rays hitting the sensor area changes.
In which case PF could be related to the angle the light hits the emulsion (film) or micro lenses (digital)
So yes, lens settings have an impact on the result, but maybe not due to any flaw.
I wonder if there is any correlation between telecentricity and reduced PF?
[/quote]
I was only saying it is lens related, not necessarily (purely) optics related. FWIW, it could be caused by/related to/influenced by internal lens reflectins and/or reflectins of the last element(s). Furthermore, IMO it is likely that if it is also sensor related, it could well also be emulsion related to some degree. I can think of a few scenarios that could make this possible, and IMO it is telling that it is less pronounced with emulsion than with sensors.
Anyway, as mentioned, nobody has come up yet with a proper explanation by what it is really caused by.
Kind regards, Wim
Hi Wim
I'm not sure that the fact that PF diminishes with stopping down necessarily indicates there is a lens involvement directly.
As you stop down, I think the angle of the light rays hitting the sensor area changes.
In which case PF could be related to the angle the light hits the emulsion (film) or micro lenses (digital)
So yes, lens settings have an impact on the result, but maybe not due to any flaw.
I wonder if there is any correlation between telecentricity and reduced PF?
[/quote]
I was only saying it is lens related, not necessarily (purely) optics related. FWIW, it could be caused by/related to/influenced by internal lens reflectins and/or reflectins of the last element(s). Furthermore, IMO it is likely that if it is also sensor related, it could well also be emulsion related to some degree. I can think of a few scenarios that could make this possible, and IMO it is telling that it is less pronounced with emulsion than with sensors.
Anyway, as mentioned, nobody has come up yet with a proper explanation by what it is really caused by.
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....