[interested_observer]

Evening,

About 6 months ago I took some shots of some antique cars at the Model T Factory in downtown Detroit. The backlighting from the windows was pretty bad, and I bracketed all the shots with 5 frames +/-2ev. Anyway, I have been working on them on and off since then and finally decided to print a few. I printed one at 20 x 30 and overall it came out stunning - with one small problem - that I have tracked down. I went back to the original and redid everything, because I wanted to remove some purple fringing (the DA 12-24 is famous for this), and I also checked off enabling the lens profile correction for the 12-24 in LR4. Well when I picked up the print at Costco - for $8.99 you cant beat the price, it looked wonderful. Then, I started seeing some digital "sawtooth" artifacts. I knew it was not the printing, and I knew the original RAW images were fine, and really the only thing that I had added was the CA removal and the lens correction.

Well, the lens correction was the culprate here. The more I looked, the more instances I found, all over the image. At a distance, it looks like a million dollars - however, up close - its another story. I went back and reprocessed the whole entire image, without correcting the lens, and its just fine as expected. Other times when I have used the lens correction it has been just fine - but this time, in this instance - it's performance was just terrible.

I was just not expecting this. In any case, it was a $8.99 well spent.

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[Adam]

Profiles for correcting fringing can be problematic, since fringing comes in many flavors and intensities. I guess this one really screwed up and actually worsened the image!

Automatic corrections rarely work for me, I typically just de-saturate the fringes to make them less prominent.

[Michaelina2]

...lens profile correction for the 12-24 in LR4....

Since LR4 is somewhat out-dated, did you consider trying the same using the current edition of Lightroom (LR5.4)? They offer a time limited trial copy that's free for the asking.


Also, you did not mention your lens-camera pairing. If using a K-5, or later (if not, check your manual for this feature), and knowing in advance that the 12-24 can produce CA on occasion, did you activate the in-camera lens CA correction feature before taking the shot?


I've found keeping my post-processing software current and employing the tools provided by the hardware manufacturer goes a long way towards minimizing disappointment.


Just curious... M

[interested_observer]

Since LR4 is somewhat out-dated, did you consider trying the same using the current edition of Lightroom (LR5.4)? They offer a time limited trial copy that's free for the asking. - Actually I should do this.


Also, you did not mention your lens-camera pairing. If using a K-5, or later (if not, check your manual for this feature), and knowing in advance that the 12-24 can produce CA on occasion, did you activate the in-camera lens CA correction feature before taking the shot? - Yes, it was the K5/12-24 combination. No, I did not have the in camera lens CA correction enabled. I always shoot raw and tend to forget about the in camera corrections. I was not really expecting the CA, but not surprised by it either. Its not really apparent on any single image, but when they are stacked - it is there. Considering the strong back lighting, it was something that I should have expected.


I've found keeping my post-processing software current and employing the tools provided by the hardware manufacturer goes a long way towards minimizing disappointment. - I can't argue with that.


Just curious... M

[Just1MoreDave]

Another thing to try is the Pentax software. The lens correction there should be the same as the in-camera stuff. The downside is workflow. You probably have to do the CA correction first, maybe other RAW-specific settings like WB, then export TIFFs to do the exposure blending. That may mean another compromise.

An alternative: hang the print where no one can get that close to it.

[interested_observer]

Another thing to try is the Pentax software. The lens correction there should be the same as the in-camera stuff. The downside is workflow. You probably have to do the CA correction first, maybe other RAW-specific settings like WB, then export TIFFs to do the exposure blending. That may mean another compromise.

An alternative: hang the print where no one can get that close to it.

That approach had not occurred to me as of yet - Thanks! The workflow would just be substituting the Pentax utility for LR4. I was getting ready to upgrade to LR5 anyway, also.

[Miguel]

Also consider using the Adobe lens Profile Downloader to see if alternate profiles exist for your body and lens. Perhaps something is better out there.
A couple of years ago, I created and uploaded to the Adobe database a lens profile for the Tokina version of this lens on a Canon 7D. This was prior to any Tokina lens profiles being included with the baseline Lightroom release (like they are now).

M

[Smeggypants]

Since LR4 is somewhat out-dated, did you consider trying the same using the current edition of Lightroom (LR5.4)? They offer a time limited trial copy that's free for the asking.


Also, you did not mention your lens-camera pairing. If using a K-5, or later (if not, check your manual for this feature), and knowing in advance that the 12-24 can produce CA on occasion, did you activate the in-camera lens CA correction feature before taking the shot?


I've found keeping my post-processing software current and employing the tools provided by the hardware manufacturer goes a long way towards minimizing disappointment.


Just curious... M

Like any software LR4 doesn't change over time. I still use LR4.1 and it's exactly the same as wehn I first installed it.

[mee]

Plus I don't think they changed anything with the lens profiling from 4 to 5. (that is, outside of perspective correction)