Chromatic Aberration & Canon 70-200 2.8 IS USM

[elmo_2006]

Good evening....


I took some images the other day and noticed a few images with some fair amount of CA. It was a clear sunny day and thesubject was wearing sunglasses and this is where the CA is seen.


This is not a bad photo, but I have another that I consider to have more CA.


My question is "is this normal forthis lens and if not what steps are there that I can take?" My apologies as I'm still a 'noob'!


I've inlcuded a sample image (cropped)and some Exif data, please keep in mind that I had the lens hood on anda Hoya HMC SUPER UV[0] filter in place. Anyopinions/suggestions aregreatly appreciated.


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Camera:
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Canon EOS Digital Rebel XSi ("http://community.the-digital-picture.com/cameras/canon/eos_digital_rebel_xsi/)
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Exposure:
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1/3200 sec
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Aperture:
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f/2.8
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Focal Length:
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70 mm
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Exposure:
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0.00
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ISO Speed:
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200
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Exposure Bias:
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0 EV
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Flash:
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Off, Did not fire
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[Daniel Browning]

I've inlcuded a sample image (cropped)





I don't see any CA in your sample image. It's normal to have a very slight amount of green CA at the wide end (70mm) and red CA at the long end (200mm) on the focal plane (what's in focus). It's also normal to have some CA on the out of focus parts of the image, but I don't know how much.

[elmo_2006]

Hi Daniel...


SorryI could not include a larger image, and my terminology may be incorrect. But if you were to look at the sunglasses, in particular the right side, you will see some 'fringing' taking place. It's more noticeable via the following link:


http://www.flickr.com/photos/icymonkey/4090885045/sizes/o/ ("http://www.flickr.com/photos/icymonkey/4090885045/sizes/o/)


Thanks so much for the response.

[Daniel Browning]

Thanks, now that I look at the larger size image it's easier for me to see it. I see the Purple Fringing on the specular reflection on the sunglasses. I don't know for sure, but I would guess that that amount of PF is normal for that lens.

[elmo_2006]

I've posted a similar thread in another forum, and was informed that it could also be due to the sunglasses on the subject, is this possible or make sense?

[Daniel Browning]

I've posted a similar thread in another forum, and was informed that it could also be due to the sunglasses on the subject, is this possible or make sense?
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It's definitely possible. PF is often caused or exacerbated by infrared light. If the sunglasses reflect more IR than visible light, it may cause more PF than glasses that reflect IR and visible light equally.