Dealing With Chromatic Aberrations

I have heard it oft said that chromatic aberration is easily dealt with in post processing. I have also heard it stated that lenses designed for digital bodies are better equipped to minimise CA's than older lenses.

Chromatic aberrations annoy the hell out of me and I find neither of the above to apply to me.

I find certain lenses to be quite prone to CA. For example the DA12-24 and the DFA100 (at wide apertures). The FA43 often shows some too. Some of my older lenses I find to be very resistant to CA. In fact I found the DA35/2.4 to be more prone to aberrations than the K35/3.5. So I stuggle to see how modern lenses are better in this regard.

My techniques for dealing with CA are basically to convert to mono or to desaturate the purples or blues. The latter doesn't work when there are other purples or blues in the scene that I wish to remain. I have Lightroom 3 and the slider to supposedly deal with CA doesn't seem to work well, it either does little or changes one colour fringe to a different colour but the fringe remains.

So any advice on how to deal more effecticely with CA would be appreciated.

One way that does work well is to shoot JPEG and switch on the CA removal option. It does reduce it very dramatically, provided that it's a Pentax lens that the camera will recognise.

The downside is that the extra processing takes time.

Thanks John. I will try that out of interest by converting RAWs to JPEGs in camera, which I presume will give the same result? Or RAW+. But I need my RAWs.

I have found that both DA and non-DA lenses do have some CA in certain circumstances. Then again, many of my lenses will or won't show CA depending on Aperture or indeed the body it is on. For example my 16-45 hates my K-5, but is fine on the K20D. My SMC-M 50mm F1.7 hates my K10D but loves my K-5. All very bizarre.

So, I use photoshop and cameraRAW which have sliders to reduce the CA on all lenses. They work very well indeed.

What gets me is how a lens can be different on bodies, aperture and indeed filters. yet there is no consistancy. old lenses, new lenses, filters, no filters, aperture, light, contrast etc.
The arguements of old lens + new body, old body + new lens, sensor out resolving lens, lens out resolving sensor etc etc does not really hold water.
All it is, is the combo of Light, Aperture, lens, sensor at the given shot that seems to be the issue. I may be wrong on this but this is how I have found the situation with CA.

Lightroom has a very handy tool for dealing with CA.

Upgrade to lightroom 4

The LR3 CA Sliders have been reduced to a single tick box and that works well. LR4 also has two fringing eradication sliders and colour ranges.

Simply use the eyedropper to click on the offending fringing and it is auto removed. the local adjustment brush in lightroom 4 can do a whole lot more including be used to mask off areas which you don't want touched by teh CA/Fringing removal or local apply it.

The other benefit of LR4 is your images will look better overall as the processing 'engine' has been updated. The LR4 noise reduction is particular is much better than LR3

What Smeggy said ...

The LR 5.2 CA tick box works startlingly well. Before I bought LR 5.2, I had been used to dealing with CA using a PTLens plugin - but LR does the job much more easily and seemingly more effectively too.

Andrew

It's good isn't it

Is LR5 much better than LR4? Both for CA removal and in general.

I cannot answer that, as I didn't have LR4. You can download the 30 day trial of LR5 and find out whether the improvement is enough for you.

Previously, I used Photoshop Elements 8 and a number of plug-ins - Grant's tools, PTLens and Colormancer noise reduction, to do stuff that Elements either didn't do or didn't do so well.

I must say I am very impressed with LR5.

Andrew

L5.2 now has a feather slider on the clone tool which is nice. Just thought I'd mention that.

Lightroom 5 from Lightroom 4 is a vast improvement for addressing a lot of corrections. If you shoot RAW and wont to process images quickly and easily.

Personally I think you can almost do everything in Lightroom now and it does it vey well with incredible control. Photoshop obviously will always provide the most creative enhancements, but if you wont to control noise, CA's and WB it really is a very good piece of software at a vey reasonable price.

If you do need to carry out manual work using a de-saturation technique, the problem can be that whilst the colour can be removed, a grey tone or brightness reduction will remain. But I have found (in Photoshop Elements) that you can restore this brightness following colour removal with a pull up on the Luminace slider (this is in the Hue / Saturation dialogue.)

Its best to select the CA fringe first with the selction brush set to just wider than the fringe so your colour removal and luminance changes are isolated to this narrow zone.

I haven't upgraded to LR5 yet but I don't think the CA and fringing controls have changed.