Your Advice please!

[Brian]

Last week I put up a post called "Rheola Store", a black and white image and we had a bit of a chat about it. But Polly noticed that there was a fringe around the trees in the background, against the sky and once you noticed it, it was quite bad. So I had a look at the original, which I share here, straight from the camera, but re sized. Although it's not too bad in the original, to get some depth into the sky, I brought the saturation right up, before going into Topaz for the final mono conversion. I've added a detail of the trees in its saturated form which looks awful. Now...........can someone please tell me what caused it in the first place and how to avoid or fix it.

[Brian]

Thanks very much, Judy. It looks like you're right. I've just read the article and my image just about ticks every box for Chromatic Aberration. I've obviously heard of it but never fully understood it or even noticed it before. So it's been a good day today........I've learned something. Now to try to avoid it!

[Brian]

3 hours ago, Judy said:

I've had it a few times  with sharp contrasts or when I've over sharpened, especially against blue sky.

You can reduce it in ACR.

You're right, Judy. I went back to have another look at the RAW file and reduced the sharpening and it helped a fair bit. Also had a look at YouTube and there are a lot of tutorials covering it that I'll have a look at.

Edited January 23, 2016 by Brian

[ChrisLumix]

8 hours ago, Brian said:

Last week I put up a post called "Rheola Store", a black and white image and we had a bit of a chat about it. But Polly noticed that there was a fringe around the trees in the background, against the sky and once you noticed it, it was quite bad. So I had a look at the original, which I share here, straight from the camera, but re sized. Although it's not too bad in the original, to get some depth into the sky, I brought the saturation right up, before going into Topaz for the final mono conversion. I've added a detail of the trees in its saturated form which looks awful. Now...........can someone please tell me what caused it in the first place and how to avoid or fix it.

 

That's chromatic aberration, some of the worst I've ever seen. Have you seen it on other shots from the same lens?

[Clicker]

It can usually be alleviated  when processing from RAW  file  Brian .. There is a defringing option ....       I use it quite often It's usually noticeable with dark tree branches and bright skies .... 

[Ryewolf]

The kit Canon 75-300mm lens that I have, under certain circumstances, sufferes from the same problem. Not noticed it on the Canon 24-105mm L or the Sigma 150-60mm lenses I have though.

[Brian]

Thanks, Polly and Chris. I've just had a good hard look at the set of images that I took on the day in question and learned quite a lot about my Canon 10-22 lens. It seems that at 10mm the fringing is quite bad, but not quite so bad at 22mm. In between isn't bad at all. If I get the chance, I'll do some proper testing today and see what is the best focal range for my lenses. I've added the same detail as above but this is straight from the camera with no saturation boost and you can see it's still there but the high saturation exaggerates it. 

[Craftysnapper]

The purple fringing has been made more obvious by incresing the saturation also you have a white halo around the fringing this is caused by sharpening and/or increasing contrast.

All lenses will show some fringing to one extent or the other if a fine tracery of leaves and branches are shot against a bright/white  sky.

[Black Pearl]

As Paul said all lenses will show chromatic aberrations to a degree (some are very well corrected but tend to be hideously expensive) so it needs to be dealt with (corrected) via software.

If you shoot in-camera jpegs's then it shouldn't ever be an issue as modern camera processors are programmed to correct CA's and other issues such as vignetting and actual distortions.
If you shoot raw then you need to either select the appropriate lens profile within your raw converter (assuming it hasn't done so by itself upon import) or manually correct them with the tools provided.

[Brian]

1 hour ago, OlympusPaul said:

The purple fringing has been made more obvious by incresing the saturation also you have a white halo around the fringing this is caused by sharpening and/or increasing contrast.

All lenses will show some fringing to one extent or the other if a fine tracery of leaves and branches are shot against a bright/white  sky.

 

59 minutes ago, Black Pearl said:

As Paul said all lenses will show chromatic aberrations to a degree (some are very well corrected but tend to be hideously expensive) so it needs to be dealt with (corrected) via software.

If you shoot in-camera jpegs's then it shouldn't ever be an issue as modern camera processors are programmed to correct CA's and other issues such as vignetting and actual distortions.
If you shoot raw then you need to either select the appropriate lens profile within your raw converter (assuming it hasn't done so by itself upon import) or manually correct them with the tools provided.

Thanks, Paul and BP. I always shoot in RAW and haven't noticed it so much in the past. I think what made it so obvious in this instance is the over saturation to give the sky a boost, before going mono. Something else to look out for.