12-03-2010, 10:52 AM
[quote name='popo' timestamp='1291365255' post='4726']
It also fits that true APO lenses wouldn't suffer from it.[/quote]
It has a lot to do with lens correction. Maybe it's related to the angles at which light hits the sensor... but that still doesn't explain why there can be PF in the center and not get worse toward the corners. Wish someone could chime in on this... I'm a bit lost apart from the observations I've made.
[quote name='popo' timestamp='1291365255' post='4726']
I don't want to put words in your mouth, but that reads as you found indication confirming DxO's claims. Of course I'll wait and see the full report.
[/quote]
From my early measurements, this actually is the indication. But I want to be sure... what they said was that manufacturers alter ISOs in fast aperture lenses due to the light loss. This implies it's a f-number specific thing. I need to check for that. And I want to check if they do this only for wide lenses more than long ones. That's about 4 tests right there.
GTW
It also fits that true APO lenses wouldn't suffer from it.[/quote]
It has a lot to do with lens correction. Maybe it's related to the angles at which light hits the sensor... but that still doesn't explain why there can be PF in the center and not get worse toward the corners. Wish someone could chime in on this... I'm a bit lost apart from the observations I've made.
[quote name='popo' timestamp='1291365255' post='4726']
I don't want to put words in your mouth, but that reads as you found indication confirming DxO's claims. Of course I'll wait and see the full report.
[/quote]
From my early measurements, this actually is the indication. But I want to be sure... what they said was that manufacturers alter ISOs in fast aperture lenses due to the light loss. This implies it's a f-number specific thing. I need to check for that. And I want to check if they do this only for wide lenses more than long ones. That's about 4 tests right there.
GTW