Understanding fringe?

Question

Are we having fun yet?

Thanks so much for your explanations about the dreaded purple fringe. Some of that I knew and much of it I did not.

My original question asked whether fringe came from the sensor, the lens, or both. I do believe that it comes from both, but I now believe that the lens is the more significant contributor. Once you see my sample, you will understand why I say this. If fringe was merely caused by the sensor, you would not see the pattern that I observed. Whether a "good" lens will give less fringe or not remains to be investigated.

See http://www.flickr.com/photos/samfeinstein/1209211393/ and read the commentary and come back and answer the question, "What do you think?"

Interestingly, I was not expecting to ever use this image for anything but a geometric study. I used to weld and do some minor steel construction and I really appreciate the precision of this structure. You have to realize that you are looking at something about 30 feet wide.

After looking at a few more examples - including my own - I realize that the pattern I have observed is probably peculiar to the nature of this shot. It is comprised of all straight edges with stark contrast between two practically monochrome fields and that may be a special situation. The examples still show that the "cheap" lenses are worse than the "good" lenses, though.

Saying a lens that is wonderful except for severe chromatic aberations is like saying your ... I can't even think of an example I can put here! You love your car, except that the wheels are square?

I have just read a piece that says (repeatedly) that lenses are worse for CA when used wide open or near wide open. I suppose that's something that I can test myself. I may even have test shots available already, as I have some some series (like that crystal vase) using many different apertures.

Answer 1

its the lens i believe (could be wrong), i find a full frame (5d) with a 14mm L series doesnt fringe

wheres the pentax F1.4? that wont do nasty digital things -haha

Sorry Dr like to be more helpful, cant wait till you share your findings

thanks

Dr re the nikon vs canon thing, maybe a canon L series lens via an adaptor onto the D200 will fix it? haha sorry thats not funny! haha

a

Answer 2

I believe it is the lens, like you said. I have shot with a 50mm 1.8, a 55-300mm VR, a 30mm 1.4, 85mm 1.4, and a 20mm 2.8 lens. All these came up superbly. However, when I bought a 55-300mm from Promaster, I noticed a lot of purple fringing. It is an excellent lens, but anything where it shows a lot of contrast will also show a lot of fringing.

Answer 3

I'd vote for lens.

I used to shoot with Nikon's cheapie 70-300 G and I got that sort of stuff all the time when shooting wide open and even when not.

I traded it on Sigma's high-buck 70-200 f2.8 HSM and 1.4X converter and I haven't had a single case of it since.

I think it's a case of YGWYPF (You Get What You Pay For).