12-03-2010, 12:36 PM
[quote name='genotypewriter' timestamp='1291373550' post='4732']
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]
Longitudinal CA is due to the different focus planes for different wavelengths of light right? That applies regardless of where in the frame you are hence can apply equally in the middle as well as the edges. Actually, that could explain why you can also get PF on the (apparent) focal plane as commented by Markus, since there is actually not one but a region dependant on wavelength. Or am I missing something here?
Looking up some samples, I got my colour direction mixed up. It is purple on or in front of the focal plane for the Canon 85mm f/1.8, and green behind. Some early test samples:
![[Image: duck1.jpg]](http://i213.photobucket.com/albums/cc260/popotehrawr/lyd/i14/duck1.jpg)
![[Image: gif2.jpg]](http://i213.photobucket.com/albums/cc260/popotehrawr/lyd/i14/gif2.jpg)
Note these may be cropped so look worse than if I had kept full frame. Is this LoCA or PF or are they the same thing?
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]
Longitudinal CA is due to the different focus planes for different wavelengths of light right? That applies regardless of where in the frame you are hence can apply equally in the middle as well as the edges. Actually, that could explain why you can also get PF on the (apparent) focal plane as commented by Markus, since there is actually not one but a region dependant on wavelength. Or am I missing something here?
Looking up some samples, I got my colour direction mixed up. It is purple on or in front of the focal plane for the Canon 85mm f/1.8, and green behind. Some early test samples:
Note these may be cropped so look worse than if I had kept full frame. Is this LoCA or PF or are they the same thing?
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.