PBase

Well...what do you think. I think it's just too much CA (purple fringing). They are taken with Nikon D50 and the Sigma 18-50 f.2.8 Macro HSM

http://web.comhem.se/spacedebree2/DSC_4426.jpg
http://web.comhem.se/spacedebree2/DSC_4437.jpg
http://web.comhem.se/spacedebree2/DSC_4440.jpg

Regards,
Fredrik

Are you shooting in RAW?
I'm often able to fix purple fringing in Photoshop CS3 Raw before I change the image to a TIF. And, that's exactly where it always is...on the edges of trees and leaves or anything dark against a bright white background.

Sigma is garbage

photographybygeorge wrote:Sigma is garbage

Sigmas 28-105 and 55-200 work great on my Sony A200, could be the Nikon's problem!

heez10 wrote:

photographybygeorge wrote:Sigma is garbage

Sigmas 28-105 and 55-200 work great on my Sony A200, could be the Nikon's problem!

Chromatic Aberration is not caused by the camera. It is a common effect seem most frequently in wide angle lenses caused by the lens not focusing all the colors of the spectrum on the same plain (your sensor). It's pure physics. Most prominent when shooting high contrast. The root cause lies in short cuts in the optical design and construction which are a direct result of trying to hold the price down. It's more common in consumer priced lenses than in top end pro gear. I would hazzard a guess that if you look closely enough at any color wide angle photograph, you can find some degree of CA. Usually way out at the far edges.

Start here:
http://en.wikipedia.org/wiki/Chromatic_aberration
http://www.dpreview.com/learn/?/Glossar ... ion_01.htm

photographybygeorge wrote:Sigma is garbage

i shoot almost exclusively Sigma because of the lower costs, and I don't have that big of a problem with CA, except under really bright cloudy days or humid winter days. however, many Sigma lenses do have some QC problems, so if it's a new lens, return it for a replacement, and try out lenses until you get a good one. i get fewer CA problems with Nikkor lenses, but it doesn't mean they're perfect either, same goes for red ring Canon lenses.

moxfactor wrote:

photographybygeorge wrote:Sigma is garbage

i shoot almost exclusively Sigma because of the lower costs, and I don't have that big of a problem with CA, except under really bright cloudy days or humid winter days. however, many Sigma lenses do have some QC problems, so if it's a new lens, return it for a replacement, and try out lenses until you get a good one. i get fewer CA problems with Nikkor lenses, but it doesn't mean they're perfect either, same goes for red ring Canon lenses.

I totally agree...I used to read DPR a lot, one person would bash Sigma, Tamron, Canon, Nikon, etc. on specific lenses or cameras, while others would vehemently defend. I think quality control can often be the issue with many things. There are some "clunkers" out there though....So maybe best to try a few and see if it's design or QC issues. I've got only one Sigma lens but am very impressed with it for the cost (not all Sigma lenses are economical either)...Some of their lenses are very highly rated. From what I've seen there can be a lot of variation in the lenses, cameras in a specific model.

the recent entries from Sigma are extremely excellent in terms of lens quality, even DPR can't say much bad against it. 50mm f1.4, 12-24mm f4-5.6, 150-500 f5-6.3 . all 3 DG(full frame) lenses, all 3 quite amazing in terms of price and quality, and very little problems with CA.

so please stop with this elitist BS or i'll have to start raving the power of the Summicron all over your behind.