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Photography Question 
Francisco M. Langit
 

Why is there a blue glow?


 
 
In my pictures, objects that are against a white background have a blue glow. I'm using a Canon G5 with an attached wide angle lens. Why is there a blue glow? Is something wrong with my camera? What should I do?


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1/17/2006 1:39:00 AM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  chromatic aberration
Not really something wrong with your camera, just a limitation of the lens and/or digital sensor.

A graduated neutral density filter can lessen the effect by lessening the contrast at the tree line. I suspect there are also digital editing fixes.


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1/17/2006 2:05:59 AM

 
Craig m. Zacarelli
BetterPhoto Member Since: 2/3/2005
  thats it Jon. The dreaded blue/purple fringe!
Ahhhhrrrrggggg!

Ps it the heck right off.
Craig-


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1/17/2006 7:16:16 AM

 

BetterPhoto Member
  In looking at the enlargement in your portfolio, It looks like you have got an atmospheric haze problem. Though the neutral density filters will help, my suggestion is to use a polarizing filter. This will not only help with the blue, but will also enhance the colors. You can enrich your color saturation using a polarizer.


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1/17/2006 11:09:17 AM

 
Andrew Laverghetta
BetterPhoto Member Since: 9/13/2004
  yes, chromatic aberration


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1/18/2006 10:02:17 PM

 
John Rhodes
BetterPhoto Member Since: 2/24/2005
  Francsco, Of course the best thing is to not have the blue fringe in the first place; but we all experience the problem from time to time.

What I do is select the portion of the horizon (mountains in this case, then invert the selection. Use the clone tool to copy the cloud or sky, and then clone over the fringe. Use small "bites" and move along the edge until the fringe is covered.

John


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1/19/2006 6:31:51 AM

 
Craig m. Zacarelli
BetterPhoto Member Since: 2/3/2005
  there are some free programs out there to fix this but I cant think of the names right now. ps has a fix for this too but it never really helps me much so I just use the color picker, choose the closest "normal" color to the blue fringe, then ues the magic wand tool to outline the fringe and replaceit with the color I picked, then its just a matter of cleaning up the surrounding spots.. its a bit time consuming but it works. The clone tool is a good suggestion for this too.
Craig-


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1/19/2006 6:59:18 AM

 
anonymous A.    Purple fringing like this is more typical of digital cameras at high ISO settings, but it really looks like a chromatic aberation which is fairly common when you use screw-in from element wide-angle or telephoto lenses.
If that is what it is, UV, polarising filters and other solutions are not going to sole the problem and may make things worse...the more glass you hang in front of the lens, the more chance of getting your red, green and blue lightwaves focussed at different planes, which is what causews this in the first place.
Software fixes are the only realistic solution. The ones that are supposed to fix purple fringing or noise will may not be much use here, but a useful and fairly quick fix is to duplicate the layer in PS, PSP or whatever, promote the bottom layer and use the MOVE tool to drag it down a bity, so the cloud in the background layer is lower in the frame. Then go to the new duplicate layer and use the ERASE tool to remove the fringing. As you do, the cloud from the layer below will show through. If you rub out a bit too much above, it won't really matter, it will still be the same cloud, the texture and colour will match. If you rub out too much below, it will just look like the cloud on the mountain. And if it doesn't, erasing with the right button down "unerases" whcih is a lot easier to control than cloning.
Good luck.


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1/19/2006 4:58:27 PM

 
  Thank you Andrew. I was trying to think of the term.


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1/19/2006 7:34:13 PM

 
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