06-14-2011, 10:17 PM
1. : No, this is not CA. What you are seeing is purple fringing (PF). Closing down the aperture, or shooting less contrasty scenes will "cure" it.
Q1: No lens profile will "correct" the PF. Either avoid it in manners stated above, or minimize its impact by desaturating the purple colour or selective replacing it with other colours.
Q2: PF is not CA. The PF you see only occurs when a LOT of light hist the sensor. When stopping down the lens, less light will hit it, and less PF will occur on edges around bright areas. When there are no such bright areas, PF will not occur.
CA is something optical, nothing to do with the brightness of the light. It will occur all over the scene toward the edges, but be most visible in contrasty edges. The CA of that lens is quite low, but PF wide open can be high.
Q1: No lens profile will "correct" the PF. Either avoid it in manners stated above, or minimize its impact by desaturating the purple colour or selective replacing it with other colours.
Q2: PF is not CA. The PF you see only occurs when a LOT of light hist the sensor. When stopping down the lens, less light will hit it, and less PF will occur on edges around bright areas. When there are no such bright areas, PF will not occur.
CA is something optical, nothing to do with the brightness of the light. It will occur all over the scene toward the edges, but be most visible in contrasty edges. The CA of that lens is quite low, but PF wide open can be high.