Bob wrote: First, this is not a flame. It's simply an observation of the losses
involved in using Photoshop, Paint Shop Pro or other software tool to
accomplish the functions provided by a shift lens. It should be obvious that
after the fact "correction" of distortion necessarily involves introduction
of errors and/or losses.
Photoshop is indeed a great image manipulation tool. Nevertheless, to
achieve the same perspective control, pixels (information) must be lost
and/or pixels must be synthesized (information summarized from surrounding
pixels) to produce the effect. Shift lenses do not have this limitation. The
perspective control provided by shift lenses does not involve loss of
information, nor does it require information be synthesized.
You can overcome this by over-scanning (increase dpi) so you have lots available to make the correction. I have done many interior and architectural shoots and it has not been a problem for me. The only thing you can't do in photoshop is to use the T/S to increase the depth of field while keeping the shutter speed up (low f stop).
Cameron
