I have a new T3i and am seeing a blue outline around the subject?

[accusrce]

I have a new Canon Rebel T3i.  I am noticing a distinct blue outline in my photos.  What may cause this?

[ebiggs1]

Just what is a "distinct blue outline" ?

If you are referring to a blue cast over the picture, than most likely you have the white balance set wrong. Or you could have selected the wrong picture style.

Set the white balance to "AWB" and the picture style to "Standard" and try again. 

[accusrce]

Thank you for your response.  The white balance is AWB and the pic style is standard.  It's not a bluish cast, but a very distinct outline around part of the subject.  One of the photos is an eagle landing in the nest...there is a blue line going up the back of the eagle, one of the tree limbs is blue, and a twig or two in the nest is blue. 

[hsbn]

From your description, it must be the effect of chromatic aberration. It's a lens defect on high contrast object (dark object against light background). It can be corrected in post processing to some extend. You can read more here: http://photographylife.com/what-is-chromatic-aberration

Kit lens and lower grade lens tend to have a lot of CA. This is inevitable. That's why people pay ton of money to get good lens because good lens are well CA-corrected (but it doesn't mean it's CA free).

[ScottyP]

Yep. It sounds like Chromatic Aberration, a/k/a "purple fringing".. Usually it is technically magenta or green, though depending on the color of the background, and one's eyes, it could sometimes be described as blue-ish or just dark. Take a shot of some winter tree branches with a bright sky behind them and you will see it clearly. That is the classic shot lens reviewers use to demonstrate CA in a lens.

It is one of the easiest things to cure in post processing, though. Especially if you are shooting RAW. In Adobe Lightroom you just check a box (lens corrections Y/N) and it pretty much eliminates it.

[ebiggs1]

Just out of curiosity what lens did you use?

[accusrce]

Thank you everyone for your responses.   Yes, chromatic aberration is exactly what it is and I've been able to remove it in post processing.  The photos in question were taken almost exactly as suggested in one of the responses...winter tree branches against a bright blue sky.   The lens is a "kit" lens, so low quality...thought it would be good enough to learn with, and I am learning, lol!  The lens is EF75-300 f/4-5.6 III.  Thanks again!