DSLR blue hue round lighter colours, help! (1 Viewer)

I've noticed recently I sometimes get a blue plume round a bird I'm photographing e.g. the little egret I photographed tonight. I'm using a Pentax *ist Ds with a 650 - 1300 telephoto lens, film speed was at 400, speed was down to about 1/60 or 1/90th, all settings were on default for saturation/sharpness/contrast, 6Mb photo, and the aperture would have been round about F11 (lens was at approx 900mm) The attached pic has been cropped but no other adjustment apart from downsizing to 150k. I don't like to change the pic too much apart from cropping and maybe a little sharpening and have tried reducing the blue on adobe photoshop elements 3 but with very little success. I would be really happy if anyone who has had this problem could maybe give me a pointer for getting rid of the haze round the bird. My thanks in anticipation.

Keith Bruce.

T. Keith Bruce said:

I've noticed recently I sometimes get a blue plume round a bird I'm photographing e.g. the little egret I photographed tonight. I'm using a Pentax *ist Ds with a 650 - 1300 telephoto lens, film speed was at 400, speed was down to about 1/60 or 1/90th, all settings were on default for saturation/sharpness/contrast, 6Mb photo, and the aperture would have been round about F11 (lens was at approx 900mm) The attached pic has been cropped but no other adjustment apart from downsizing to 150k. I don't like to change the pic too much apart from cropping and maybe a little sharpening and have tried reducing the blue on adobe photoshop elements 3 but with very little success. I would be really happy if anyone who has had this problem could maybe give me a pointer for getting rid of the haze round the bird. My thanks in anticipation.

Keith Bruce.

Click to expand...

Keith

I have the same problems sometimes, so in Photoshop I go to the Hue/Saturation and change to the Blue channel. Move the slider in the minus direction until it has gone. Hope this helps

Thank you Christine, I should have thought of that. Doh! Wonder if this is a common prob with DSLR's.

I usually get it when I take birds with a white background (Cloudy Sky). Once a found this way to get rid of it. I don't trash as many shots.

I used to get it often with my Nikon 70-300G lens, but haven't suffered since getting the Tamrom 200-500 Di. Perhaps newer lenses, which are tweaked designs for digital, help to remove these abberations???

I agree with rezMole - Colour fringing is a sign that you need to spend money on better optics to resolve the problem.

Check this out

http://www.birdforum.net/showthread.php?t=31522

My shots of a pair of little egrets was spoilt with exactly the same problem when using the 75-300 lens. They were almost unusable. Shooting with the 135-400 I notice hardly any fringing on the same high contrast subjects. The expensive glass on the most expensive lens is there to tackle the problem of colour fringing and to ensure the image remains in focus across the frame.

Also in Photoshop CS using the raw format files convertor you can attempt to correct for colour fringing caused by the lens.

Robert

If you have Photoshop on a Windows machine, the freebie plugin here should help this photo :
http://www.sd3.info/pf828/PFree/PFree0-1.html

Thanks for the tip this looks useful I will download and have a play.

Robert

T. Keith Bruce said:

I've noticed recently I sometimes get a blue plume round a bird I'm photographing e.g. the little egret I photographed tonight. I'm using a Pentax *ist Ds with a 650 - 1300 telephoto lens, film speed was at 400, speed was down to about 1/60 or 1/90th, all settings were on default for saturation/sharpness/contrast, 6Mb photo, and the aperture would have been round about F11 (lens was at approx 900mm) The attached pic has been cropped but no other adjustment apart from downsizing to 150k. I don't like to change the pic too much apart from cropping and maybe a little sharpening and have tried reducing the blue on adobe photoshop elements 3 but with very little success. I would be really happy if anyone who has had this problem could maybe give me a pointer for getting rid of the haze round the bird. My thanks in anticipation.

Keith Bruce.

Click to expand...

In addition, Keith, when using that length of lens, you will probably find it helps the picture to use as fast a shutter speed as possible to minimise the effect of movement in the subject or slight camera shake

Shoot RAW then use the Photoshop Raw filter advanced menu to remove the Aberration. It works very well. Failing that, you can use the sponge tool in photoshop to desaturate the area. I know this is photoshop specific and you are using GiMP, but this is how I deal with the problem.

Actually, better optics has very little to do with this type of problem - color fringing. It is caused by the angles that the light is hitting the image sensor and the quality of the sensor. Most of it is caused by over-saturation of adjoining sensor-wells. Those extra electrons spill over into adjacent ones. If the light rays are coming in at wider angles due to the focal length of the lens and lens design itself (pricey doesn't always fix this issue), this can also exacerbate the problem. This is why you will see it even more prevalent at the edges of photos that suffer from it than the center. (This is different from lateral chromatic aberration which is completely dependent on lens design and I won't go into that here.) One of the easiest ways to minimize color-fringing when you find it happening is to stop down your aperture. This will help prevent some of the wider-angle light rays (coming in from the edges of your lens) from hitting each sensor-well sideways and preventing some of that "spill-over". This helps, to a point, but if you stop your lens down too much or completely then another problem enters the issue, diffraction effects. There's always a sweet-spot for every lens and each of its focal lengths (if a zoom design).

One of the better programs I've found to handle this is a tool in Paint Shop Pro 9. You select the fringe color or colors (as many hues as you find) with small selection boxes that you want it to correct, select their average width in pixels for each hue range, and it tries to pull colors from adjoining areas back into those fringes while desaturating the original color-fringe hue.

Lateral chromatic aberration (edges of red-green-blue appearing more prominent as you reach the corners), is caused by the different spectra focusing to different distances. This is the one that most blame on inexpensive lenses or pricey but poor designs. That problem is handled better by other software. But since that's not the problem displayed in your photo I won't go into better solutions for that. The above described tool in PSP helps with this issue, but is by no means the right one.

p.s. I just took a look at that PFree plugin that was suggested above. It looks like a great addition to throw into the tool-box. From what I've read so far it seems to do similar things as the one built into PSP 9 (just not as easily). Thanks for posting that link, I'll be passing it on to others that don't care to use PSP just for that tool.

This is known as Chromatic aberration and is caused by the lens. You may improve this by stopping down the lens (using a higher F n.o)
Also some CCD's bloom when under a lot of light.Stopping down here MIGHT help.