Originally posted by alohadave You are using the word 'perspective' the same way the rest of us are using 'width'.
You also seem to be using the word 'perspective' to describe 'convergence'.
I don't know how to illustrate an angle in PSE, i'll bet you that if you compared the red lines on your picture, only looking at the portion covering the doors, you'd see that the angles are identical (although, it looks like the pictures were not taken at the same angle, but the distance looks pretty close).
You are now dealing with your person definition. I am simply dealing with the common definition of both perspective and linear perspective in photography--you can check something like the
Focal Encyclopedia of Photography. And that example clearly shows linear perspective.
Your idea that I can change the size of the second image, which is just a crop of the first (although you could not recognize them perhaps because of the change in perspective), so that the lines match. But since linear perspective is radial, I can take any picture taken at any distance, at any focal length, with any crop, and register the radial line through scaling. That only proves that linear perspective is radial, but we know that.
The point is you do not display images in proportion to the format, the crop, or the focal length. Display size is held constant in that you make your images the same relative size regardless of the process.
I have shown a clear example that perspective does change though cropping or a change in focal length while keeping the camera position the same.