Correcting Lens Distortion in CS3

chuckinsocal

Hi Gang,

I was out with my new 18-135 today and took the shot below at 18mm, some lens distortion to be expected.



The grid shows that the column just left of center is is almost perfectly vertical while the column on the far right is leaning heavily to the left. I tried to correct this distortion in Filter/Distortion/Lens Correction but no matter what I did with the sliders, if I corrected one column, another would distort. Couldn't get them all parallel. It's almost like I have to twist the image somehow. Any Suggestions? Thanks.

David_S85

Always correct the barrel distortion first (Canon now has that in DPP for registered lenses, if you are a Canon shooter). Or use PTLens.. a $15 CS3 plug-in. Best product of its kind for this type of correction. Check first if your lenses are included in the release.

Then, use CS3's Free Transform to pull out the perspective distorted sides of the photo, straightening up the columns. Crop. Save.

PTLens also has a perspective correction function built in.

When you find situations such as these when you shoot, it is best to think through the workflow and shoot a bit wider than you think the finished cropped photo will be. Barrel distortion and perspective correction will force you to toss away much of your shot by the time you crop it.

chuckinsocal

Thanks David ... that's a big help.

Actually, I found the error of my ways. I had straightened the image using that middle column as a guide so that's vertical then I tried to deal with the distortion. Doesn't work so good.

I went back to the original image and used Transform/Distort to manipulate the corners so it looks much better. Not perfect but better.

I'm definitely gonna download that plug in cuz it looks like I'll need it for the wide end of my lens. My lenses are fully supported. Haven't fully tested the long end yet.

Thanks again for your help.