06-15-2011, 07:06 PM
[quote name='popo' timestamp='1308162350' post='9264']
It simply isn't bright enough to make the fringing obvious on the focal plane. I think I can come up with a quick and simple way to demonstrate that...
![[Image: loca1.jpg]](https://lh4.googleusercontent.com/-C6Fi5e6Rz_0/Tfj3DdFKA_I/AAAAAAAAGmk/_KCLbhKo5BU/s800/loca1.jpg)
![[Image: loca3.jpg]](https://lh4.googleusercontent.com/-GWdB7KYW4r8/Tfj3EAyHBQI/AAAAAAAAGms/zTS16KGX4Vg/s800/loca3.jpg)
Both shots taken using the Canon 85mm f/1.8 wide open. Right one is exposed about +3 stops compared to the left one by varying shutter time. Focus was manually set to make the line beginning "Earth" sharpest in the left shot, and was not touched again. Note in the higher exposed shot the onset of purple appearing on what was the best focus, and is even apparent on the line behind it.
[/quote]
I said "such bleeding", not that one can not detect still some purple from OOF areas on "in focus" areas.
Try shooting a sheet IN THE FOCAL PLANE, not at such an angle. Do it is bright as you want. It will NOT give similar purple bleeding into the dark from the bright as the original poster's image shows. It is not LoCA.
I am sure that you can actually see the difference of what occurs in the OP's image and the LoCA test page, even though both are kinds of purple artifacts.
It simply isn't bright enough to make the fringing obvious on the focal plane. I think I can come up with a quick and simple way to demonstrate that...
Both shots taken using the Canon 85mm f/1.8 wide open. Right one is exposed about +3 stops compared to the left one by varying shutter time. Focus was manually set to make the line beginning "Earth" sharpest in the left shot, and was not touched again. Note in the higher exposed shot the onset of purple appearing on what was the best focus, and is even apparent on the line behind it.
[/quote]
I said "such bleeding", not that one can not detect still some purple from OOF areas on "in focus" areas.
Try shooting a sheet IN THE FOCAL PLANE, not at such an angle. Do it is bright as you want. It will NOT give similar purple bleeding into the dark from the bright as the original poster's image shows. It is not LoCA.
I am sure that you can actually see the difference of what occurs in the OP's image and the LoCA test page, even though both are kinds of purple artifacts.