Ellen, what you describe is called barrel distortion. It is common in wide-angle and zoom lenses. The preferred solution is to use a longer prime lens or set your zoom lens to a mid-range focal length, where barrel (and its opposite, pincushion) distortions are minimal.
If you can’t do that for some reason, click Filter>Distort>Lens Correction and correct it with the Remove Distortion slider.
This is a good plugin for that. It finds the lens, and the focal length that you used, through the EXIF tags and acts upon a database of lenses.
Works perfectly, as long as you correct before cropping or anything.
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http://www.epaperpress.com/ptlens/>
Rob
Joe and Rob, thank you for your suggestions. I was really in a bind, and very frustrated trying to figure out how to do it.
I’ve got the cs version, and it does not have a lens correction filter. So the ptlens plugin was perfect. It was exactly what I needed!
Many, many thanks to you.
Ellen
Ellen, it’s good that Rob pointed you to a plug-in that solved the problem for you.
I’m sorry I didn’t know that CS lacks the Lens Correction filter. Does anyone know of a source that lists which versions introduced which features? The need to know such things comes up frequently here. It would be very helpful to have a comprehensive reference in the form of a time-line diagram that depicts the introduction or enhancement of each Photoshop feature.
Doesnt the transform functions perform this type of correction, or are we talking about automated corrections?
You’re right, Joe. It would be good to have a feature/version list.
Donald, in CS, there is no function in transform to correct barrel distortion. You can’t straighten out a curvature. Or at least I haven’t figured out how. Even manually.
Ellen,
Glad it helped.
Before I used Ptlens I, sort of, used the pinch distortion filter. I doubled the canvas size, pinched the whole image, then cropped again.
The method wasn’t good and it was also unpredictable, and lacked a preview.
Images with strong verticals need it often (when shot at the wide end of the zoom range) for barrel distortion, but at the same time are very unforgiving as far as the method is concerned.
Rob
Ellen, i think you are correct in that conclusion. just wanted to let you know about the transform adjustments in case you never used them.
Thanks, Donald. I use the transform>skew all the time to square up copy shots of paintings, so I don’t have to be so precise squaring it up in camera. It’s a great tool.
Rob, I never knew about the pinch distortion. It’s a logical work around. But really, this ptlens is terrific, especially because it has my lens in it’s database.
The grid toggle is great, too. Does photoshop have that? I always am adding guide lines, one by one, to have a guide to square things up. It’s rather tedious, toggling a grid would be much faster.
Does photoshop have that?
Yes: View – Show – Show Grid.
(or Ctrl-‘)
Rob
Wow, do I feel like a dummy. There is was, all along, almost in plain sight!
Thanks Rob.
