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View Full Version : Focal length question...



Integrity
02-12-2005, 04:09 PM
I don't know a whole lot about optics, and I am confused on the focal length settings in Lightwave's virtual camera.

The manual says that the zoom factor setting of 3.2 is equivalent to a 24 mm lens, but I thought that the zoom factor (maximum zoom factor anyway) of a real camera is the maximum focal length divided by the minimum.

I'm also a bit confused on how a zoom factor of 1.0 is equivalent to a 13.3 mm lens in Lightwave.

When I set the focal length to 0 (well near 0, it won't let you go all the way down), 0 would be a 180 degree field of view. That makes sense...but why does a zoom factor (and also a 13.3 mm length) equal a 90 degree view. Not only that but why is the field of view measured from the horizontal/vertical view of the screen instead of the diagonal of the lenses circular projection.

I'm confused because different lenses have different lengths and was wondering is Lightwave's "lens" is a variable zoom lens with it's minimum length at 0...and this would be why everything is the way it is.

ingo
02-13-2005, 02:44 AM
I too have no clue what the zoomfactor is all about, but 3.2 is equivalent to a 42,7 mm lens here, with the normal 35mm camera. And it would definitly nice to see the diagonal fov like it is noted with all camera lenses.