It's especially bad with my tele lens, a Canon EF 75-300mm 1:4-5.6 III. I wasn't happy with that one right from the start, but now I think it's getting worse. My pictures today turned out awfully. Please view http://www.catmom.de/2012/ca.jpg to see what I'm talking about. I really think the degree of chromatic aberrations is NOT acceptable here.
Honestly, I was so fed up with this today that I made the decision to get a new tele lens (as an early birthday/christmas present), and I hope that one will be better.
Yes, it's annoying. It's actually called purple fringing. It happens especially with really bright highlights. I've had this issue ONLY with my 70-300 lenses. Unfortunately it probably isn't the specific lens you have. http://www.brighthub.com/multimedia/photography/articles/33825.aspx
@sdpace : Thanks for the link, it's interesting to read. In the upper part of the picture (between the leaves), there's a lot of green fringing also. So you think it may be this bad with the new one also? The reviews on amazon didn't mention anything like that.
I've had it with a few Canon lenses... The 100mm macro, the 70-200mm. Not always but as @sdpace says it happens in bright highlight situations. Horrible.
This is one that I took last year that I remember having the purple fringe really bad on the highlights of the water. It's easy enough to fix, but very annoying.
Assuming that photo is a full image (i.e. not a small crop of a much bigger photo), that's horrifically bad. The 75-300mm isn't an amazing lens by any means, but I'm surprised to see anything that bad from any lens that isn't made out of plastic!
I presume the lens hasn't been dropped or subjected to any serious impact? To me that looks more like a misaligned element than simple bad optics.
All lenses suffer from CA to some degree, and as you would expect, expensive lenses suffer from it less! Canon's L-series lenses have low-dispersion elements in them which reduce CA a lot, as do some of Sigma's high-end lenses.
More cost-effectively, the Canon 70-300mm IS lens is a good step up in image quality from the 75-300 and adds image stabilisation, and although it won't be immune to CA, I've certainly never managed to get it to do anything even remotely close to as bad as is seen in that photo.
ha, I only use cheap lenses and I never saw this. I've a 70-320mm Pentax screw lens ($30) on my canon now and it never did this, and I have plastic holga lenses that don't do this. Just saying don't throw loads of money at this it isn't expense that's doing it. Gees I'd be super unhappy with that on my pics. Is it the camera body showing wear and tear? I don't know I shoot digital but I know more about film.
@shadowdancer The CA does seem pretty extreme in your picture, but the sun can do some crazy things. What type of filters do you have on your lens currently? Do all pictures lately have that extreme of purple or only those in bright light?
In Lightroom there is a tool to reduce CA. I haven't played with it yet, but I will when I use my 70-300 lens as I can see it on my Sigma lens as well.
@abirkill@chewyteeth@mallocarray : Well, it is cropped, but not that much, so this effect shouldn't show up this bad! I can tell you I'm more than unhappy with this result! I can't remember I dropped it, or exposed it to any impact, but it seems to me it's getting worse. But I was never really happy with this lens, CA has always been an issue (and the lack of sharpness as well). That's why I planned on getting a new lens anyway, but actually, I wanted to wait until Christmas.
I know that the light situation in this particular picture was extremely difficult, and I didn't use any filters (maybe I should have used a polarization filter?), but it shouldn't look THIS bad, right? Too much to edit with Photoshop or any other editing software, I suppose. I was also wondering if this has something to do with my new camera. I got the EOS 600D three months ago, used to have the 450D before.
I have ordered the Tamron AF 70-300mm 4-5.6 Di SP VC USD now, and I hope it's a little better. At least the reviews on amazon say that CA wouldn't be such a big issue with that lens (even though I think that there WILL be CA in difficult situations, but hopefully to a degree I can live with).
@shadowdancer I doubt a polariser would have had much effect, CA occurs in very high-contrast areas and I don't think a polariser would have reduced the contrast in this shot.
CA can almost always be removed in post-processing, but it can be a real hassle. In this shot it's actually pretty easy, as the CA colours are magenta and blue, neither of which are key components of the photo you actually wanted to take.
As such, it's fairly easy to add a hue/saturation adjustment layer in Photoshop, change the master dropdown to magenta, use the colour selection tool to click on one of the worst magenta bits in the photo, and desaturate. That can then be repeated for the remaining blue bits. The result is something like this, which took about three minutes (click for bigger):
However, had you taken a photo with a strong amount of blue or magenta colours as the actual subject, it would have been a whole heap harder, as you'd have had to do selection masks to try and select the CA and not the intentional colour. Also note that, while desaturating it fairly effectively removes the colour, it doesn't correct the loss of sharpness and light 'bloom' that remains.
(Note that Photoshop does have 'proper' CA correction as part of the Lens Correction filter, but it was nowhere near powerful enough to tackle this amount of CA)
@abirkill : thanks a lot for your advice, Alexis, and for taking the time to edit the picture. Looks so much better now! I guess I should finally try and get more familiar with Photohsop; I'm usually using Corel Photopaint for the post processing, but I don't think that one has this option. I have Photoshop 6 installed on my computer, but don't use it a lot. Need to get some practise...
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http://www.brighthub.com/multimedia/photography/articles/33825.aspx
Also, you can (sometimes) fix this easily in post, and (often) fix it with some effort.
http://blog.lorrifreedman.com/index.php/2008/07/30/hdr-and-the-purple-fringe/
I presume the lens hasn't been dropped or subjected to any serious impact? To me that looks more like a misaligned element than simple bad optics.
All lenses suffer from CA to some degree, and as you would expect, expensive lenses suffer from it less! Canon's L-series lenses have low-dispersion elements in them which reduce CA a lot, as do some of Sigma's high-end lenses.
More cost-effectively, the Canon 70-300mm IS lens is a good step up in image quality from the 75-300 and adds image stabilisation, and although it won't be immune to CA, I've certainly never managed to get it to do anything even remotely close to as bad as is seen in that photo.
In Lightroom there is a tool to reduce CA. I haven't played with it yet, but I will when I use my 70-300 lens as I can see it on my Sigma lens as well.
I know that the light situation in this particular picture was extremely difficult, and I didn't use any filters (maybe I should have used a polarization filter?), but it shouldn't look THIS bad, right? Too much to edit with Photoshop or any other editing software, I suppose. I was also wondering if this has something to do with my new camera. I got the EOS 600D three months ago, used to have the 450D before.
I have ordered the Tamron AF 70-300mm 4-5.6 Di SP VC USD now, and I hope it's a little better. At least the reviews on amazon say that CA wouldn't be such a big issue with that lens (even though I think that there WILL be CA in difficult situations, but hopefully to a degree I can live with).
CA can almost always be removed in post-processing, but it can be a real hassle. In this shot it's actually pretty easy, as the CA colours are magenta and blue, neither of which are key components of the photo you actually wanted to take.
As such, it's fairly easy to add a hue/saturation adjustment layer in Photoshop, change the master dropdown to magenta, use the colour selection tool to click on one of the worst magenta bits in the photo, and desaturate. That can then be repeated for the remaining blue bits. The result is something like this, which took about three minutes (click for bigger):
However, had you taken a photo with a strong amount of blue or magenta colours as the actual subject, it would have been a whole heap harder, as you'd have had to do selection masks to try and select the CA and not the intentional colour. Also note that, while desaturating it fairly effectively removes the colour, it doesn't correct the loss of sharpness and light 'bloom' that remains.
(Note that Photoshop does have 'proper' CA correction as part of the Lens Correction filter, but it was nowhere near powerful enough to tackle this amount of CA)