"The other mistake people often make is that widening or lengthening focal length alters perspective. it doesn't. Moving the camera close or far changes perspective, not changing focal length."

Hey kimaldis - very good point! Someting to add to my eBook text - thanks. Good references too.

Don't understand this though: "Most GP 3D apps - Maya, Xsi, Houdini - don't work in the quite limited way Vue works and with good reason; focal length is meaningless unless you take into consideration the format you're working with. And it's not a plus at all, it's a pain because it's misleading and just plain wrong."

Does it really matter if the math is that of true lenses? Is not the purpose of Vue to simulate reality, rather than to recreate it? In other words, if it looks enough like photographic lenses is that not sufficient, no matter the method? I haven't explored the Vue perspective/aspect ratio render stuff though.