New Lens Performance Question

[Mando327]

Hey Guys,

Happy New Years! Anyways, i got my Canon 24-70mm 2.8 L, and one of the pictures that i took has some cyan and red fringing. It is barely visible, but does it still mean that it's defective or something, especially since it's an "L" series lens? Should i exchange it? Below is a crop of the image. Your opinion is greatly needed and appreciated.

Thanks,

Armando

[Trevor Ash]

Was this in the center of the lens or out on the edges? What aperture was it shot at?

I wouldn't be too concerned about what you're seeing (color fringing) but I can understand why you are. The detail and color seems good (appropriate for that lens) to me. Was this shot with a tripod? What shutter speed? Heck, what camera did you shoot with?

Color fringing is usually repairable too. For example, Adobe's RAW converter has options to take care of this kind of problem during conversion. I don't personally have a lot of experience with it myself. I use a tool called Panorama Tools to correct color fringing.

Usually it's worse on the edges of a photo than the center.

I wish I could tell you whether it's normal or not for that particular lens but unfortunately I can't. If you think you have a lemon then exchange it now before you get attached to it. If you're able to do comparison shots just try and use the same camera and aperture on the lenses when you compare. I'll be interested in your results.

I attached a corrected photo....it's usually easier to correct fringing on an entire photo than it is a crop that wasn't taken from the center. The reason is because color fringing is a radial type of distortion that's best at center of lens and worst on outside edges. To correct your image I shrank the red channel horizontally but that's not usually how you can correct something like this crop.

[Lionheart]

Hey Guys,

Happy New Years! Anyways, i got my Canon 24-70mm 2.8 L, and one of the pictures that i took has some cyan and red fringing. It is barely visible, but does it still mean that it's defective or something, especially since it's an "L" series lens? Should i exchange it? Below is a crop of the image. Your opinion is greatly needed and appreciated.

Thanks,

Armando

Hate to say this, but it is quite possible you got a lemon.
Check the reviews on Fred Miranda's site on this lens ( http://www.fredmiranda.com/reviews/s...rt=7&thecat=27 ). More than a few folks who have returned this lens and exchanged it for one that works. QC at Canon isn't what it used to be. I've got the older 28-70, have had two of these (first one got stolen), and I don't recall any fringing that was visible with this lens.
One of my patients also has the 24-70L, and was very disappointed with the performance. I'll bet he got a lemon too.

[Mando327]

Hey Trevor,

Thanks for your reply. This crop was taken from the corner of the original pic. below. I shot it with the Canon 20D, at 1/80, f/8.0, ISO 200, focal lengh 24mm, no tripod.
How would i go about doing comparison tests? At a camera store or something? Have you had expesive lenses give you this sort of problem?

Thanks,

Armando

[Mando327]

Thanks Lionheart for your response. I went to the website and one of the reviewers compared two of them side by side, and this is what he said "The second one I got is beautiful. I did some tests at 24, 35, and 50mm on both lenses with the same apertures." Did Canon just sent him another one and then he returned the crappy one? How does the exchange thing work with canon?

Thanks,

Armando

[another view]

Wide zooms can do this. I have a shot from my Nikon 20-35 that this has happened with too - also shot at 20mm (it's widest setting) in the lower left of the shot. This was on slide film - and the green fringing showed up next to a white post.

This was Nikon's top wide-zoom although it hasn't been made for a couple of years, the newer 17-35 is supposed to be better. I've only had it show up a couple of times so I'm not too worried about it. If I'm going to make a print I can just Photoshop it out. Actually, if I replace that lens it will be because of the focal length with my DSLR - 20 just isn't very wide with the conversion factor.