CA Correction with PS CS RAW Converter

[Scottes]

I've been waiting for Capture One to come out with support for the 20D. And waiting. And waiting.

Finally, I got fed up trying to use PS CS's Raw Converter - I say "trying" because I was really running rather blind. So I went out and bought Bruce Fraser's "Real World Camera RAW with Adobe Photoshop CS" to learn the program correctly. It kinda hurt to pay $35 for such a small book. It hurt more when I found only that only half the book talks about RAW while the rest covers the File Browser which is useless to me.

It's worth the $35, really. And there is a section on Workflow that I haven't read so it's not *all* File browser.

And I'm not yet convinced that I'll convert to PS CS for RAW conversion, but I did learn one neat trick, and that's how to correct for Chromatic Aberration (CA from here on in).


I picked an image of a mountain scene reflected in a lake with some trees and a rotten little branch that stuck into the corner of the image. (Check the *entire* viewfinder!) The mountain had a background of mostly blue sky with some clouds, and the sun was directly behind me. After processing and final sharpening I ended up with this:

http://www.itsanadventure.com/postimages/No-CA-fix-Scene.jpg


Well that halo around the mountain is pretty darn ugly, and I deleted it and went back to the original to find the problem. Zoomed in at 100% I found the CA.

Here's a couple of 100% crops from the original:

http://www.itsanadventure.com/postimages/No-CA-fix-Branches.jpg
http://www.itsanadventure.com/postimages/No-CA-fix-Mountain.jpg


At 100% the branches showed some enormous CA, which really isn't surprising given that situation. If you shoot something thin like branches in shadow against a bright sky you should expect some CA. The mountain shows a definite halo along the left edge. Yuck.

Again, this shouldn't have been a surprise given the lighting. And to top it off I was using a zoom, so this made for even more CA. The lens, the Canon 17-40 L, is a great lens but I think any lens will show CA in the picture.


So I deleted everything and went back even further, back to the RAW opened in PS. I zoomed to 200% and went into the corner with the branches. I then flipped to the Lens tab. (If you don't see the Lens tab then click on Advanced up near the OK & Cancel buttons.)

Yuck. Gotta fix that CA.

I grabbed the "Chromatic Aberration B/Y" slider and started moving it around. Wrong. It just made the CA more green and purple when I slid it to the left and more yellow and blue when I slid it to the right. So I put that back to 0 and grabbed the "CA R/C" slider and moved that one around. Much better.

Sliding to the right made the CA more cyan and red. Sliding it to the left, not too much, seemed to help. Then I held down the Alt key when sliding, and I could see things better. Holding the Alt key hides the other channels and makes the process clearer because of this.

Nudging back and forth just a little showed me that setting "CA R/C" to -33 looked about as good as it was going to get. Then I went back to the "CA B/Y" and played with that a bit, and found that +5 made it just a little better. It looks much better, as you can see in these 100% crops.

http://www.itsanadventure.com/postimages/CA-fix-Branches.jpg
http://www.itsanadventure.com/postimages/CA-fix-Mountains.jpg

The branches are much better, but still look a little funky, but remember the lighting here. They are *not* going to look perfect. But check out the edge of that mountain - no halo!

Woo-Hoo!

So I finished resizing, processing, and sharpening. It looks a bit better, huh? The halo around the mountain isn't so apparent any more. Yes, it's still got a halo because it was sharpened, but it's hardly as bad as before. The obnoxious branches in the corner definitely look sharper, as do the tops of the trees.

http://www.itsanadventure.com/postimages/CA-fix-Scene.jpg

Before:

http://www.itsanadventure.com/postimages/No-CA-fix-Scene2.jpg


PS CS's CA correction is pretty cool. I'm happy.

[RinkRat]

Well, you sold me.

I'm ordering it from Amazon.com now... $20.99 there!

[drisley]

Great tutorial scottes.
Just like you, I've been looking at other raw solutions for the 20D until the new C1 comes out.
DPP has a couple bugs, as does EVU (at high ISO's).
So, I've been forced to use PS CS Raw.
I was never a big fan of PS Raw because of colour inaccuracies, but this latest version (2.3) seems to have solved all that, and added a few new features. To be honest, I may not even bother with C1 now. I think the image quality from PS CS Raw is now VERY close, and the integration, and workflow is more to my liking. PS CS Raw really is great when it comes to retaining detail in the shadows and highlights. Using the exposure, shadow, and brightness controls helps you access the raw images entire dynamic range. This is something no other software, even C1, can do.

[Scottes]

Rink, the book is definitely worth the $21!

Dris, I'm still not convinced that I like the color with PS CS RAW. Now I know that this just means I don't yet know what I'm doing. I still have to play a bit more with the book open.

I will say that I do not like the PS CS workflow. I **love** the Capture One workflow - it suits me *very* well.

I will probably upgrade to C1 3.6 when it comes out, but I'll kep PS CS around for fixing CA if/when it happens.

[chris.bailey]

Neat mini tutorial again Scottes. Had always ignored the advanced tags. Now off to find a couple of suitable shots to give it a go on.

[dtrayers]

Dris, I'm still not convinced that I like the color with PS CS RAW.

Scott,

Not to hijack this thread, but have you read this?

Calibrating Camera Raw in Photoshop CS (http://www.creativepro.com/story/feature/21351-1.html)?

Tom Fors (http://www.robgalbraith.com/ubbthreads/showflat.php?Cat=&Number=264118&page=0&view=collap sed&sb=5&o=186&fpart=1) has developed a script that automates iterative the process. Some have had good success with it.

I've tried it and noticed a subtle difference in the reds. That was a few weeks ago and I've not had the time to play with it since.

[drisley]

Scottes, are you using the latest Camera Raw? I think version is 2.3.
The colour is much improved over the old versions, and is very close to C1 Pro (beta) on 20D files.
I like to tweak each file individually, so the workflow for Camera Raw works best because it's integrated into Photoshop.
I find that I spend much less time converting raw images with PS than I did with C1.
Then again, I will have to wait for the next version of C1 to support the 20D before I make any final decision.
Dtrayers, thanks for that link. I'm going to go give it a read.

[Scottes]

Yes, I have ACR 2.3.

It's not so much that I don't like the color accuracy but I just can't seem to get the colors to a point where I seem to remember they looked. I just need to read and play a bit more.

But I still love the C1 workflow because it suits me well.

[drisley]

Yes, I have ACR 2.3.
It's not so much that I don't like the color accuracy but I just can't seem to get the colors to a point where I seem to remember they looked. I just need to read and play a bit more.
But I still love the C1 workflow because it suits me well.
Ah yes, that is something alot of people complain about.
Either I'm not "right-brained" enough, or my memory isn't that great, because I can never remember exactly how colours looked in real life to try to get it exactly right later. I try to get the colours to look pleasing to my eye instead.
Funny thing... I tried Canon DPP software, Canon EVU software, and now PS CS Raw to convert the 20D files. Each and every one produces completely different colour responses.

[Scottes]

I try to get the colours to look pleasing to my eye instead.

Yep, exactly. And I have a very difficult time sometimes. Now always, but often enough to be frustrating.

When I first got my 10D I never even installed the software that came with it because I'd heard that it was so slow. I tried Breeze Browser and didn't like it so I tried C1 and stuck with that. 6 or 8 months later I began to hear about people complaining that C1 blew out yellows and so on. But I didn't know any better, because C1 was all I used, so C1 was "correct" to me, because I could still get the colors to look pleasing to my eye.

Now, with a 20D and no C1 support, I have to look at other things. I tried EVU and DPP out of necessity, then BB again, Bibble too, and finally had to settle on PS CS. I'm seeing things in ACR that are better than C1, like highlight recovery and CA adjustments. By the time C1 3.6 comes out I'll probably have the colors down, too.

Yet I'll probably still go back to C1 because of the workflow.

But if C1 waits too long I'm going to end up with a different workflow...

[drisley]

Yup, C1 sure is taking it's sweet time!