Tackling HDR Chromatic Aberration

[gorgon2k]

Ok guys, I'd like to address what I feel is probably the biggest problem I see with HDRs and no it's not noise. It's Chromatic Aberration. It's those magenta and blues that seem to leak from the edges in the HDRs that in my mind, kill the picture. Here's an example...

http://farm3.static.flickr.com/2676/4222441352_d86fd1af72_o.jpg



Now I know one major issue with Chromatic Aberration is Lens quality, But many of us don't have the cash to throw around at $2,000 dollar lenses. So what I would like to figure out is how do we reduce this? I hear that Photomatix has a "Reduce Chromatic Aberration" feature, which for some reason mine doesn't have, but I hear it doesn't work too well anyways. I've also been reading about this program called Dx Optics Pro which can calibrate an image based on the camera and lens. It has 1600 lens calibrations on file. Their site says "Automatically correct distortion, vignetting, lack of sharpness, chromatic aberrations and colored fringes with a module adapted to your lens/camera configuration. More than 1600 camera-lens combinations calibrated!" so I'm going to get this program tonight, do a little experimenting, and I'll let you know the results.. in the meantime, do you guys do anything in particular to address this issue?

[Simply Ravishing]

I just do my best to ignore it... haha

But I know what you mean, it drives me crazy, let me know how that program works out.

[wolfden]

hmmmm, interesting to find out your findings. I see it has a one month trial.

[gorgon2k]

This program is such a pain in the butt, im going to try to go a different route. The issues with transferring from Lightroom to the program and the program reading EXIF data are just too much to ignore.

[Gary McDuffie]

I haven't had to face CA in HDRs yet, but I have done a little correcting in regular shots from time to time. Obviously I haven't tried this, but wouldn't it work to pull the raws into ACR and make the CA adjustments there and then export them as tiffs and let Photomatix, or whatever program you prefer do its thing from there? I've found the CA adjustments in ACR to work very well.

[gorgon2k]

Lightroom does a decent Job at elimination CA. The selling points of the DxO program was that it automatically adjust for each lens. But oh well. The place that i Noticed the issues with CA the most in HDRs is around distant trees and objects that contrast strongly. (I.E. a tree in a bright sky, building against a bright background, etc.) the problem is that there's minor CA already existing and Photomatix just amplifies it. What im gonna try is taking a shot that I know will produce CA, doing an HDR straight from the CR2s and doing one after I edit out the CA in lightroom and export as TIFFs.

[rustyjaw]

The problem with using any tool that works on lens profiles is that once your shots have gone through the tonemapping process, they no longer exhibit CA like they do straight out of the camera. So I would assume that kind of CA correction would be too slight to be effective. Unless you can create your own presets, I suspect it's not going to work.

If the CA is noticeable, the only method I know of that eliminates it entirely is to use adjustment layers in Photoshop. I use a "Hue and Saturation" adjustment layer, and desaturate the colors in the aberration. Typically it will be Magenta or Cyan (sometimes red and/or blue as well). I fill the adjustment layer mask with black (which nulls the effect) and paint in white over the aberrations, applying the effect only to those areas.

Keep in mind that you can fine-tune the exact range of the H&S with the slider at the bottom of its palette/dialog box.

Sometimes I need to create more than one H&S adjustment layer if different saturation adjustments interfere with each other.

Yes, for some shots this can be a painstaking process, but a lot of the time it only takes a few minutes to complete.

Also, FYI, sometimes using Photomatix's "Align images" command prior to tonemapping can help reduce CA. Even if you shot on a tripod, subtle movements can make CA even worse, IME.

[mukster]

That picture looks vaguely familiar :P

I have just downloaded that software and will give it a whirl once I have loaded it up. Appears you get 30 days of trail, right? Dunno if some of the functions are disabled, but I will run the original picture through it and post a link to it in my original thread, here:

http://photography-on-the.net/forum/showthread.php?t=801735

[carboman]

I too have problems with CA in my HDR. It's quite bad especially where the tree branches are. I cropped out the ridiculously bad portion. I tried reducing the CA within Photomatix and also in Photoshop but it doesn't work. Perhaps I should process it further by exporting it back to Lightroom and try cleaning it up there?

Note: I shot it handheld, adding some truth to what rustyjaw wrote.

http://jamiepang.smugmug.com/photos/754424715_cFtnT-M.jpg

[HPADON]

This is my first post on the forums. Thought I'd throw my 2 cent's worth out.

I tone map, save as a 16-bit TIF and then open that TIF in Camera RAW. I use the Fringing/Vingetting tool in Camera RAW to pull back any CA. If that doesn't get it all, I open the photo in CS3 and, if the colors in the photo allow, lasso select the areas that have CA and use Selective Color or Hue/Saturation to pull the blues or magentas back.

Don

[JimmyG]

Doesn't the latest version of DPP also have a lens profiling system to help eliminate CA and other ill-effects?

[Harlz]

I can't say I've come across very much CA in my HDR shots. There probably is some but for me the overwhelming challenges is too much dynamic range in my scenes for 3 bracketed exposures (and doing 5 manually is a pain) and wind/movement/people ruining my shots. I'm only using a 50D and a Sigma 10-20mm with usually a polarising lens, nothing that special there.

[Electric Shepherd]

Well I've recently bought DXO having had the trial version and I've been impressed with its lens correction abilities which seem to outdo DPP even.

To the original poster, what did you use to convert your original starting images, ?Camera Raw. You might try DPP as a starting point otherwise as should have a free copy, otherwise give the trial of DXO a go.

[TweakMDS]

Without correcting, CA seems to be amplified by HDR in many situations...
I follow this workflow for shots with heavy CA on my Tokina 11-16:
First, I process the images with DPP (since it handles CA slightly better than ACR / lightroom). Save as 16 bit TIFF.
Second, I inspect heavy risk areas like high contrast windows for more CA. If it's still annoying me, I desaturate the areas by selecting the color (purple fringe mostly). Save as TIFF again.
Then I either use photomatix standalone or CS3 to make the HDR merge and tonemap. This choice is based on the amount of ghosting that will be in the image. I find that the photomatix standalone is better at reducing ghosting if you have water ripples and/or moving people. Sometimes it's a good idea to take several identical brackets to further (manually) reduce moving people...
If I have both ripples and moving people, I make two identical tonemaps in photomatix and layermask them in photoshop.

After this, I do some final curves and whatever else seems needed in photoshop.

This image needed most of that:
http://farm4.static.flickr.com/3621/3418026177_77ae04dc50.jpg (http://www.flickr.com/photos/mdstoop/3418026177/sizes/o/in/set-72157616379237337/)

[Bollan]

I agree with you that CA can be a hassle in HDR and the process usually further increase it. The way to go is to try to correct the CA as much as possible on your original shots before starting the merge. LR and DPP are pretty decent on reducing CA while DXO is even better to be honest.

[Karmadillo]

Well I've recently bought DXO having had the trial version and I've been impressed with its lens correction abilities which seem to outdo DPP even.

To the original poster, what did you use to convert your original starting images, ?Camera Raw. You might try DPP as a starting point otherwise as should have a free copy, otherwise give the trial of DXO a go.

Referring back to the original post, doesn't DxO only support high end lenses such as Canon L series? It certainly doesn't support any of my Sigma lenses (all top-of-the range). Defeats the purpose of eliminating chromatic aberration without spending thousands on a lens.

I just installed the latest DPP. Canon have changed the software so it disables distortion and chromatic aberration correction tools for photos shot with non-canon lenses. Luckily I have the original version of the software to fall back to.
Sure, I don't expect the software to automatically correct the aberrations of other company's lenses, however disabling the manual sliders for other manufacturers lenses is harsh.

Adobe camera Raw 6.4 (part of CS5) does a good job of both lens and chromatic aberration, but there are some color cast issues for 5DmkII cameras that need solving. This will probably become my tool of choice once all issues are ironed out. It supports all of my lenses out of the box, with fully automatic correction and batch processing.

I am currently using PTLens. This can be used as either a Photoshop Plugin or standalone. It automatically corrects lens distortion to a high quality, allows manual chromatic aberration, supports batch processing, and is cheap.

[kirkt]

@Karmadillo:

Check here:

http://www.dxo.com/us/photo/dxo_optics_pro/for_your_equipment

for your combination of camera body and Sigma lens, as DxO supports many sigma lenses, as well as non-L canon lenses. You can also request a camera body/lens combination to DxO.

One can also use Adobe Lens Profile Creator to make their own lens profiles for use in LR/ACR.

Kirk

[magwai]

the latest version of photomatix has an option to remove CA. seems to work pretty well.