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[OM] Automatic aberration correction on new lenses.

Subject: [OM] Automatic aberration correction on new lenses.
From: Moose <olymoose@xxxxxxxxx>
Date: Wed, 13 Aug 2014 03:29:07 -0700
µ4/3 lenses communicate with the cameras, which in turn include data used to correct aberrations in Raw conversion or post processing. I'm only addressing linear distortion here.

As I mentioned before, my use of the Panny 12-32 kit lens for the GM1 led me to discover that the built-in correction didn't seem very good close up.

I recently ran into more such trouble getting an image to look right, which led me to do some simple testing. <http://www.moosemystic.net/Gallery/tech/DXO/LensCorrect.htm>

I assumed the 12-32 would be worse than most other lenses, as design compromises were probably made to make it so small. So I also checked the M.ZD 12-50. You can see that the 12-50 has less distortion when uncorrected than the 12-32, but still quite a lot.

Things I noted:

1. Even the best corrections leave some slight wavy, 'mustache' distortion of straight lines. My garage door is not wavy. :-)

2. Correction using the data from the lens is better for the 12-50, but then, it has less to correct. For neither is it really very good. It was identical for ACR and SilkyPix on another 12-32 image.

3. DxO and PTLens are a dead heat on the 12-32.

4. PTLens clearly beats DxO on the 12-50. Look at the bottom corners. One man show relying on samples from users bests group of paid PhDs!

5. Both DxO and PTLens lose less area around the edges of the image than 
ACR/SilkyPix

Finally, I'm glad I shoot mostly stuff without straight lines! Of course, the widest settings of wide zooms are generally worse case. Looking at a shot at 300 mm on the 75-300, there is almost no difference.

When I do shoot rectilinear subjects, PTLens is my friend again. I quite like DxO's default rendering of color, contrast, etc., compared to ACR's If I find it on sale again, I may get it.

Notes:
I thought I was using the 12-50 at 12 mm. Apparently I bumped it.
The 12-32 shots were slightly tilted. I should have just put it on the GX7, 
which has a built-in level.

Going Straight Moose

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