Brick wall, raw format before correction
The amount of distortion declines as the focal length increases, until there is almost no distortion at 105mm (22.5mm actual). The good thing is that it is quite easy to fix, although it is an extra step in post-processing that adds time.
With Photoshop Elements, use the Correct Camera Distortion tool (Filter -> Correct Camera Distortion...).
Here are the settings I use to fix distortion at various focal lengths, using the "correct distortion" slider:
- 28mm (6mm actual): +25
- 35mm (7.49mm actual): +14
- 50mm (10.7mm actual): +7
- 85mm (18.189 actual): +5
- 105mm(22.5mm actual): +1
Brick wall, corrected for distortion, before cropping
The jpeg version of this image is processed inside the camera. The camera corrects distortion, but I have found it is not corrected fully. Here is the camera-processed jpeg, with a slight barrel distortion:
Brick wall, corrected in-camera for jpeg
. . . Rob Williams