Distortion Correction and the 18-105

Started 3 months ago | Discussions thread
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TJ61 Senior Member • Posts: 1,154
Distortion Correction and the 18-105

I guess this is kind of a "D'uh!" moment for me, but thought I'd share for the equally-ignorant.

Still rather new to PP and especially Capture One, I just realized that a number of my un-cropped images, after processing the raws in C1, were coming out at less than 6000x4000; some as small as 5400x3600.

After some testing, it appears that this is due to the application of lens correction using the appropriate lens profile in C1. I'm guessing that when the correction is made in-camera, the result is upsized back to the expected 6000x4000.

While I sort of expected the same upsizing in C1, I think it's better that they leave that as a choice. Also, you have the option of getting all, or some, of your (distorted) pixels back, by dropping the distortion correction from the default 100% of the lens profile recommended amount.

I've always wondered why some people complain so much about the amount of distortion in the 18-105 -- my jpgs always looked fine to me. But I guess I kind of get it now that I see I'm losing as much as 20% of my pixels. I didn't know that was happening.

Here's an example showing an OOC jpg (6000x4000), after lens correction and cropping in C1 (5400x3600, but same FOV), and the uncorrected (6000x4000):

OOC jpg which has apparently been corrected for distortion, cropped back to rectangular, and up-sized back to 6000x4000 (note the straight bit of road at the bottom).

From the raw version, processed in C1 which corrected distortion, and cropped back to rectangular, but NOT up-sized back to 6000x4000 (note nearly same FOV, and straight bit of road, like in-camera processing).

From the raw version, processed in C1, but with NO distortion correction, and thus no cropping required to bring back to 6000x4000. Note the distorted bit of road, and a little more FOV (e.g. more of the rocks on either side).

 TJ61's gear list:TJ61's gear list
Sony a6000 Sony E 10-18mm F4 OSS Sony E 35mm F1.8 OSS Sony E PZ 18-105mm F4 G OSS
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