Paul, in the particular image that you saw, the adjustment is relatively small, and that is one of the shots that can get away with a small amount of perspective correction.
I am on extended travels right now, and won't get back to my studio for over a month, and therefore don't have access to the original file.
I have done the perspective correction on many different images, and I understand how it works. What I don't like about it is precisely what you said in your post: "you would pull laterally outward on the bottom of the image to slightly widen it". This results in a distortion of the image away from it's natural proportions. The buildings look too wide, as indeed thay have become. The building is being stretched away from it's natural aspect ratio. It becomes "fat".
Furthermore, I shot this image on 6x9 medium format for the purpose of printing it large at 13" x 19". There is an incredible amount of detail in that image because of the fine detail in the buildings. Windows and building design features are very small, especially in the distance. These details become soft or distorted when I apply more than a little perspective correction.
The image you saw was shot with a 90mm lens, equivalent to a 39mm lens in 35mm format. The building's divergence is not too serious, which is why I leave the image as it is, and don't mind to show it on the web site. The problam is with the images shot on my other 6x9 camera which has a wide angle 65mm lens, equivalent to a 28mm lens in 35mm format. The divergence of the buildings with that lens is unacceptable. And the degree of perspective correction required in Photoshop results in obvious distortions and artefacts. I tried it. I didn't like it. And consequently I don't put those images on my web site.
I appreciate the suggestions everyone is making on this forum, but for now I remain in favour of a shift lens or shift sensor. If shift wasn't important, view cameras wouldn't have it.
Regards,
Craig
