Cause of fisheye blue vignetting?

[RobSS]

hey,

does anyone know the cause of blue vignetting in lenses such as the opteka 72mm fisheye? example it almost seems like the ring holding in the lens is super thin and lets a amount of light through it. does anyone know the legitimate reason for this? cause id really like to fix it. (the video isn't mine btw)

Thanks.

 

[ElmRealmRider]

It's called chromatic aberration http://en.wikipedia.org/wiki/Chromatic_aberration and no theres no fix, the quality, type, and build of glass will usually determine wether or not theres chromatic aberration

 

[RobSS]

thanks so much for the info. i do have another question though, it seems to only appear in certain situations like in this video. i read through that wiki. article and didn't find a answer.