View Full Version : Zoom Factor Envelope

08-01-2005, 08:29 PM
I am learning Lightwave. Starting with 8.3. My question is this: I want to work with focal length instead of zoom factor. When I add an envelope the only unit of measure presented is zoom factor. Is there a way to get the graph to show in focal length?

08-01-2005, 11:02 PM
This would be a great feature request. There might be a plugin. But if you want to do the math here it is.

Assuming the default of 35 mm aperature hieght, the following math will get you there:

f (focal length) x .13333 = z (zoom factor)

Focal length of 1mm is 1 x .13333 = .13333

So a 25mm lens would be a zoom factor of 3.3325

100mm? , you guessed it 13.333

75mm lens? 75 x .13333 = 9.9997

You can quickly figure out any focal length and just enter the resulit in the graph.

If you plan on working this out for a different apurature hieght, just set it to focal length in the camera properties panel and change the aperature hieght to the desired setting and then enter 1 in the focal length field. This will give you the zoom factor below. Use this number as your multiplier (.13333 in above example)