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Old Jul 31, 2010, 9:41 PM   #1
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Default Adobe Lens Profiles

I recently upgraded to Lightroom 3 (but not CS5). One of the things that interested me about it was the ability to create and use lens profiles that will correct geometry, CA and vignetting. Since I don't have CS5, finding profiles is more problematic - CS5 can access Adobe's library storing profiles that others have created. Lightroom doesn't have that capability, so I've both been looking around for other people's profiles and creating my own (slowly).

So far I've managed one for the DA 35 macro and now that I understand how to do it (I can be pretty dense when it comes to how to do things) I've started on one for the 55-300.

Is anyone else trying their hands at this?
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Old Jul 31, 2010, 11:55 PM   #2
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I thought I saw something about this over on the Pentax Forums about Adobe Lens files, although I did not pursue reading it - since I did not realize that it was associated with LR3. I figured that it was Photoshot only. I was thinking about possibly downloading the LR3 trial and seeing what it will do. I need to standardize on some basic tools. I was hoping to do this with Bibble Labs, especially since they had lens correction - however in their new version its not there yet, especially for Pentax.

It would be nice to have a correction file for each of my lenses.

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Old Aug 1, 2010, 7:42 PM   #3
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Adobe has a separate program to create the profiles. When you download it, you'll get pdf files for the charts (a simple black and white checkerboard). You shoot the target that works for your lens/focal length at a couple of different distances, apertures etc. and then the program uses them to put together the profile. I assume they aren't as good as those done by DxO, who actually does scientific measurements, but it seems to work reasonably well. I've just finished one for the 55-300 and tomorrow I'll go shoot some brick walls - that should show whether the geometry is corrected correctly. Looking at the charts in LR, I was surprised at the CA that the 35 macro had. It wasn't huge but I hadn't noticed any so far when I've been shooting real pictures. Now the 55-300 is a different matter!

I really like LR and have been using it since the first beta. The lens profile option and the excellent noise reduction capability were enough for me to upgrade from LR2. It also has some of the nice b&w conversion pre-sets that CS4 has, something I hadn't noticed until today, a plus that I'll use.
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Old Aug 6, 2010, 12:33 PM   #4
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I've finished the profile for the DA 55-300. I thought you might be interested in seeing the difference it makes. I'm sure that this doesn't compare with DxO's scientific profiles as they shoot under controlled conditions and take exact measurements. My profile was done using a chart printed on a laser printer and taped to a TV tray propped up against a bookcase, using available light coming through my windows. I did follow the guidelines for shooting the chart (you have 9 shots for each iteration, I did iterations for several different apertures and a number of different focal lengths, which also changed the distance).

Here's a comparison - they are 100% crops taken from the upper left area of the shot (not the extreme corner, I cut off all of one column and most of a second one on the left). The picture is the chart you use for calibration. The shot is one of the raw files taken from my series of shots at 300 mm and at f8. I imported it into LR3, created a virtual copy of it and applied the profile I created to the copy. Then I exported both versions to CS4 and cropped them the same, pasting the crops side by side into a new file (so the exif info isn't there).

You can see how the profile corrected both the geometric distortion (you can see a certain amount of that in the original, but the crop doesn't really show the extent of it) and the CA (not really any vignetting to correct). It doesn't do anything for the sharpness of the shot, the tripod was on carpet with shutter speeds between 1/6 to just over a second, and all of the shots I took show more softness than I normally see with regular shooting.

I think that these profiles are pretty nice, considering the cost is only some time spent shooting boring charts - not $$ spent on a different program. Keeps processing simple. I'm happy I took the time to create the profile, and i'll definitely use it.

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Old Aug 6, 2010, 5:54 PM   #5
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Thanks for your efforts I'm tossing up between software at the moment so this is very interesting.
Simon.
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Old Aug 6, 2010, 7:09 PM   #6
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thanks for posting this Harriet, ive yet to upgrade from lightroom 2 but this is sure tempting.

The amount of time spent to make the profile surely will shorten the time spent in PPing your shots!
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