both focal length and distance should change perspective/zoom
15mm should provide a lot of persp distorsion but you would have to get camera close to the object
something like 600mm should be near orthographic (and zoomed closely too) and camera would have to be further away from the object
i’m just curious whether focal length in zbrush relates to real world 35mm camera (because the one in 3ds max seems like it does)
another slightly annoying thing is the perspective distortion changes as you hide and show various parts of your sculpt.
Now that is genuinely messed up and annoying. Can make multipass rendering of scene elements problematic.
It can be worked around with transparency though…the perspective stays constant as long as elements are simply “invisible”, and not “hidden”.
peekoot not only the focal will change your perspective!
the ratio of the image will too
You can keep perspective constant while sculpting this way:
Add a sphere as a subtool. You need to disable UVs for all subtools (except the sphere) for this to work. Make sure the sphere is centred on the mesh’s pivot point, then resize so that it just encases the whole of your model. Now make a new blank white texture (256x256 will do, as size is not important), press Texture:Invert to make the texture black and then Texture:Transparent. The sphere will disappear. Now, as long as the eye icon is switched on for the sphere subtool you can sculpt any portion of your mesh without any changes in perspective.