Purple Haze

[Rob Powell]

I know the photo is out of focus I am not too worried about that bit.

What I want to know is why do I get this purple haze around the edge of the bird?

 

[tirediron]

Chromatic aberration; or "CA". It's something that occurs, most noticeably in less expensive lenses on borders of high-contrast. It's generally relatively easy to fix in post production, especially if you're using a tool like Lightroom.

 

[sscarmack]

I believe it (ca) gets worse in out of focus areas?

Maybe I'm wrong.

But since the bird is obviously out of focus, the CA looks a lot worse than it would if it were IN focus.

 

[Rob Powell]

Thanks for that that is very helpful.

I am using GIMP 2 for post production do you know how would I go about fixing it?

 

[tirediron]

I'm not sure if Gimp has a 'fix'; search for 'CA correction Gimp' or similar phrases.

 

[Alexr25]

That is a good example (or rather a bad example) of CA, chromatic aberration. It's a common lens fault where different colours are focused at different point on the image plane, all lenses suffer from CA to some extent but this is a really severe case. It shows up in high contrast areas and is usually more pronounced at the edges of the frame. Stopping down the lens does help reduce CA and programs such as Lightroom have good tools to deal with it after the fact.

 

[Alexr25]

You can get get a plug-in for Gimp to remove (reduce) CA. Don't know how well it works as I don't use Gimp but the tool in Lightroom is very effective.

 

[Rob Powell]

Cheers guys really helpful information much appreciated. FYI the lens I was using was a Kelda 420-800mm telephoto zoom so not the most expensive of lens but I thought I would try it out.

I will check out the add on with GIMP and see if that helps.

 

[astroNikon]

When I first started taking photos of aircraft I was getting some purple haze around the plane (which was slighlty out of focus due to speed). As I increased shutter speed the purple haze disappeared. This is on a Nikon 300/4 lens. So try increasing you shutter speed and see if that helps.

 

[480sparky]

I'm not sure if Gimp has a 'fix'; search for 'CA correction Gimp' or similar phrases.

Darla's Purple Fringe Fixer.

 

[Rob Powell]

Will try increasing the shutter speed as you suggest. This was a first attempt with this lens and shooting a moving object would obviously be better with a faster shutter speed. Not sure what this was set on.

Thanks sparky will work through your link.

 

[Soocom1]

I’m going to chime in a bit here for a moment.

I have owned several similar lenses in the past, mostly on older film cameras with much the same problem. Even when the subject is still.

The lens you mentioned has the elements all in the front with no rear element which is where some of the issue comes into play. The CA can be very bad with some of these lenses and past experience has taught me that the lenses work best with a clouded day or no direct sunlight.

If possible, try to fit a sun shade on the front and avoid overly bright areas. This will help some but results will vary.

 

[Joves]

Basically the problem as always is shooting a darker subject against a bright background. If you are going to use this for shooting birds against the sky try throwing on a circular polarizer. That will at least get rid of some of the washout, and cut the CA down a little. You will have to up your ISO to get some decent shutter speeds, but hey it happens. My 10.5 fish does this when I am shooting indoors, and there is a bright opening in the room somewhere. I cannot use a CP on that, they do not make one for it.

 

[LatentTom]

Thanks for that that is very helpful.

I am using GIMP 2 for post production do you know how would I go about fixing it?

You could try using a saturation/hue adjustment in Gimp. Select saturation/hue then select the magenta channel then slide the saturation bar to the left. I have had pretty good results using the same method in PSE11, except PSE11 lets you use an eye dropper to select the color you would like to alter.

 

[table1349]

Are you sure you didn't buy the Jimi Hendrix version of that lens?