Correcting Lens Aberration (DPP, PTLens, DXO)

[zigzag]

I have a 17-85mm lens and want to always correct its barrel distortion etc. Same

for the 10-22mm, 50 f/1.8, 70-200 f/4L I also have Adobe CS3.

 

I see that DPP3.2 has a correction feature (page 53 of the manual) but

(surprisingly) I don't see my 17-85mm lens listed as compatible (or 70-200, 50mm

f/1.8) - the list of compatible lenses is not extensive - and after that my 30D

is ruled out for compatibility with a few of the listed lenses. The reason I

don't use DPP normally is workflow - I import with Bridge, run some actions,

post process in CS3.

 

I have a trial version of PTLens (http://www.epaperpress.com/ptlens/) that lists

not only a much larger number of Canon lenses but also many other cameras. This

costs US$15 for a license and is a Photoshop plug-in (so I can create an import

action that presumably can run it every time.)

 

There is also DXO which looks like it may be very good.

 

To me (because it's a PS plugin) it looks like the PTLens solution is very cheap

and also possibly the best solution for a large range of cameras and lenses. The

few trial photos I have tried it on seem to have their distortion well corrected.

 

There is one other option which I suppose I could investigate - using CS3's (or

ACR's) Lens Correction function - but it seems this must always be image specific.

 

Is there any downside to this? (Obviously Canon know more exactly what their

lenses will do.) Anyone use PTLens a lot and have an opinion?

[JDMvW]

I've worried about this too, as I also have a 17-85mm. Normally I put up with the little problems it has because it's so good all around. Nonetheless I have been hunting for a solution--even downloaded the DxO, but hadn't got around to using the trial version, nor was I quite sure what parts of the thing I needed or not. Anyway, if you have Photoshop CS3 go to Filter>Distort>Lens Correction and you will find a screen that allows you to correct barrel or pin-cushion distortion, color abberations, and perspective too. All very handy to make the 17mm shots more like what they should be. Perhaps the other programs are better, but since I have Photoshop, I'll use that for the time being. I'd be glad to hear from those using other programs why they think theirs is better.<div></div>

[chrisjb]

Glen, there`s a free lens correction plugin on this site, have not tried it yet but looks similar to the cs3, sliders for pincusion & barrel dist

http://www.photo-plugins.com/Plugins/Plugins/

 

HTH

[zigzag]

Here's a couple of examples of what PTLens does as a Photoshop action at it's default settings (i.e. you can batch it.) Chris - yes CS3 has that built in.

 

No#1 is the Canon 10-22mm @ 10mm.

[zigzag]

Img 1.

[zigzag]

Img 2 is the Canon 17-85 lens @ 17mm.

I had hoped that batch correction would retain a rectilinear image - but of course that cannot be true - you still have to go back to each image and crop for the new composition.<div></div>

[robin_sibson1]

Although I have seen plenty of positive comments about what DxO can do, for example the (now rather out-dated) article on Luminous Landscape

 

www.luminous-landscape.com/reviews/software/optics-pro.shtml

 

nevertheless there are a number of reasons why you might not want to tangle with it. One is pricing structure and level, changed recently but still arguably over-pricing the product hugely given the alternatives. Another is licence management, which I believe involves the program injecting something into core Microsoft code that you can remove only with special software tools or through a system re-install. To me, that's totally unacceptable, even if the modification is not in any way malign

 

I have used PTLens and it is quite effective and costs only micro-money. It even works as a plug-in to PS Elements, and there is a stand-alone version as well. But unless things have changed, it does not do the job at the point where it should be done, which is during the unpacking of the RAW file, and automatic correction applies only to distortion, since its database of lenses is limited to that aspect.

 

PhotoShop does of course have tools to correct various aberrations, but, as pointed out, it has no database of lenses, so you have to work our from scratch what adjustments are needed.

 

Of the software known to me, which is probably not a complete list, that leaves you with DPP 3.2, which does the corrections as part of RAW conversion. I am very impressed with what this can do, and with the fact that ALL adjusments are supported from the lens database (but can then be tweaked by the user if desired). This is the first version of DPP with this capability, so there's every reason to think that future releases will widen its applicability, and the EF-S 17~85 lens is certainly a glaring omission from the original list. What DPP does NOT do is to provide a purely manual adjustment capability - the only manual bit is the fine-tuning on lens/body combinations that it knows about. Also, only reasonably recent bodies are supported (probably to do with how they record which lens was used), and the 20D is not among them, and only very recent bodies are fully supported, certainly to do with the fact that at least some of the corrections allow for focused distance if available. There would seem to be scope for Canon to provide firmware upgrades for some bodies (like the 5D) to enhance compatibility, but there's been no sign of that.

[zigzag]

I don't use DPP (and it doesn't support my Canon lenses) but there doesn't seem to be a way to do the Aberration Adjustment in the batch process (which seems to only do format conversion). I see the NR/Lens tool that can do the adjustments singly (and the DPP CA adjustment looks worth a try with some of my 10-22mm images.)

[rainer_t]

PTlens is among the correction SW what the 50/1.8 is among lenses ... cheap, nice and does a very decent job.

 

I use it regularly on images where distortion really bothers me. (Main use is for the 17-85 in the 17-20 range).

[stevepamp]

I use both DPP and PTLens and find that both work very well. Generally if I convert using DPP I'll use it for lens aberrations, and if I convert with C1 I'll use the PTLens photoshop plugin. I can't tell the difference quality-wise, but the PTLens plugin is more configurable.

[lester_wareham]

"There is one other option which I suppose I could investigate - using CS3's (or ACR's) Lens Correction function - but it seems this must always be image specific."

<P>

I mostly do it that way. I do an incoming test on receiving a lens with a high contrast target, if the CA is more than a certain value I find the correction settings by trial and error looking at the high contrast target black against white line at 400%. I then save this as a ACR template file, normally one for each whole f-stop and one for for every focal length marked. I find that I can neglect subject range.

<P>

The template files pop-up in the context menu if the Bridge thumbnail is right clicked in bridge or can be applied within ACR itself.

<P>

It seems almost all lenses can be fixed in this way quite well and doing this at RAW level rather than being forced to use TIFF or PSD secondary masters.

<P>

The only lens I found that the CA did not fit the Photoshop correction algorithm was the 18-55mm kit lens.

<P>

This shows a plot of the measured CA correction of a 28/1.8 lens on a 20D.

<P>

<IMG SRC="http://www.zen20934.zen.co.uk/photography/LensTests/EF_28mm_f1.8_USM/Plots/Corner%20Chromatic%20Aberration%20Avg.jpg" ALT="PLOT">

<P>

100% crop f1.8 corner uncorrected for CA

<P>

<IMG SRC="http://www.zen20934.zen.co.uk/photography/LensTests/EF_28mm_f1.8_USM_AS_A/f1.8/Crops/K.jpg" ALT="PLOT">

<P>

100% crop f1.8 corner corrected for CA

<P>

<IMG SRC="http://www.zen20934.zen.co.uk/photography/LensTests/EF_28mm_f1.8_USM_CAC_A/f1.8/Crops/K.jpg" ALT="PLOT">

<P>

[JDMvW]

Lester, much thanks, I've reread your post a couple of times, and I think I finally get it. Much obliged.

[zigzag]

Thanks Lester/all. I will investigate the ACR/Bridge method and compare with PTLens. One thing I will also check is where the 17-85mm distortion becomes not noticeable on people/group shots - if it's past 20mm then it's maybe not an issue.

[gdanmitchell]

<p>I'm sold on LensFixCI. It is quick, simple, and very effective - but it is customizable for

those who might want to twiddle with it.

 

<p>I don't use it on all photos, but when I can see, for example, distortion of straight lines

near the edges of the frame I do use it. The results are quite good.

 

<p>I posted an <a href="http://www.gdanmitchell.com/2007/09/16/a-test-correcting-

lens-distortion-in-post-processing/">example of a corrected image</a> at my web site. I

can maybe convince myself that when I look at a 100% crop of the far corner that there

might, possibly be a barely detectible difference between the processed and unprocessed

images on screen - but it is completely inconsequential in prints.

 

<p>Dan

[zigzag]

Thanks Dan - that's interesting - I will take a look at LensFixCI also.

[al_avery]

I second Dan’s recommendation of LensFixCI from <a href="http://www.kekus.com/software/plugin.html">Kekus</a> though I have experience with an earlier version. It seems to be the Mac equivalent of PTLens. Also it uses the PTLens database plus it’s own which comes in at over 500 lenses at this point. The new version also appears to process RAW files.