I have followed the 2-3 threads in the last couple of days on the advantages of digital stitching to replicate using a 4x5 or 8x10 camera with film and have a couple of questions...
If the desire for a stitched digital photograph is increased resolution to compete with 4x5 film resolution when scanned, won't you have to use a different lens for the multiple digital captures compared to what would normally be used for a similar field of view?
For example, if I use a 180mm lens on a 4x5 camera I get 47° angle field of view (using the diagonal of the 4x5 film). For a single digital capture using a Nikon camera (1.5 crop factor) if I wanted a similar angle of view I would use a 35mm lens with gives me a 44° angle of view with the Nikon digital sensor. Pretty close to the 4x5 view. This is straightforward using the diagonals of both formats.
Now is I want to increase the resolution of the digital by stitching several frames together then I will have to change the lens to one giving a smaller angle of view than the normal lens in order to get the same angle of view with the total stitched image.
Is this thinking correct on stitching digital images for higher resolution. If you just pan left and right or even up and down using a normal lens giving a similar angle of view, then you would actually get a much wider field of view. Correct or am I off base here?
I do see that if I use a much smaller field of view lens for the stitched image then I can increase the resolution of that image. For instance, a 135mm lens on a Nikon digital sensor gives a 12° field of view which is about 1/4 the field of view using a 4x5 camera with a 180mm lens. So using an double row of 6 digital shots (6 on top and 6 on bottom) to allow an overlap of the images would be an increase in resolution from about 12MP to 170MP.
Am I off base with these calculations and the way to look at stitched digital photograph resolutions?