Lens Correction and Manhattan Skyline

Posted by Philip in Follow-up, Photo Processing

Since I got the request to do my same lens correction test for a panorama, but with a cityscape, I asked Mark Schaffer of Knowsphotos if he had a few RAW files I could process.  He’s a far more traveled and accomplished landscape photographer.  You should check out his site, he posts images rather regularly.  The only thing is he uses a Nikon, but I won’t hold that against him.   ;-)   Just to be clear the original RAW files are his, and I processed them (including color correction) the same way I would have for any panorama.  So this is about as close to an equal comparison as the skyline pano I performed the same test on last week.

No lens correction applied before stitching.

Yes, I know I didn’t crop the image.  I just want you to see what comes out of the pano stitching.

Lens correction applied before stitching the pano

From this size you cant really see much difference.  And even putting the photos on top of each other at 100% shows that they are very close even along the edges.  Below is a small section of the pano at 100% where the images are in a difference mode so you can see the… differences.

This is using the Exclusion blend mode so you can see the differences.

As you can see there is not a lot of difference between the two images.  So one can conclude that with this lens, lens correction will not make a large difference when stitching panoramas.  I would hazard to guess that this would be true of 99% of  you panoramas, because the way the panoramas are stitched, the least distorted area of your lens is used for the bulk of the stitched image.  If you have any distortion, it’s generally along the edges of the picture, and you normally crop that out anyway.

So now you know and can spend some time at Knowsphotos to see some of Marks Landscape and Architectural photography.

Lens Correction and Panos?

Posted by Philip in Photo Processing

After looking into what lens correction added (or didn’t add) to my portraits, I wondered if the lens correction being applied to each individual image before stitching the panorama would help.  One would think that the lens correction would straighten out the individual images and then the final panorama won’t have that bent bowtie effect.  So I decided to do a test with the following panorama.

Panorama Without Lens Correction

After applying the lens correction and restitching I came out with the following panorama.

Panorama With Lens Correction

It’s kind of hard to tell, but it appears that the center horizontal of the panorama is a bit straighter.  But the sky appears to have even more bend to it.  So I decided to overlay the images to see how different they were.

The difference

There’s a pretty big difference and I think that applying the lens correction to the individual images before stitching does help the final image.  What do you think?  Is it a positive difference?

Lens Correction for Portraits?

Posted by Philip in Photo Processing

This feature was one of my most anticipated of the Lightroom 3 and Adobe CS5 before they came out. I don’t have any fisheye lenses and generally don’t have anything that looks distorted but that little perfectionist in me wanted my images to be correct. Now that I’ve used it for several months, I find I often forget to turn it on and I don’t miss not using it. Am I missing something or is the lens distortion not a big deal unless you have an extremely distorted lens? There is more correction as your focal goes down.

Here’s one image taken with a Canon 28-135mm at a 28mm focal length. Looking at them side-by-side so to speak, you can’t really see what’s been corrected.

Once I put one image in a difference blend mode, you can start to see that the distortion wasn’t anywhere near my subject. Black is areas with no correction.  The colored section is where there’s been a correction to the distortion and it’s in an area I would probably crop out anyway. So I don’t see a need for it in this case. Do you enable lens correction for your portraits?