Slide Projection Helpers
The picture below gives the ratio of the rectangle of typical 35mm slides.
The formula below give you a way to figure out what size image you will get at a certain distance with a certain focal length lens.
A 35mm slide is 1.378" x .90" or 23mm x 35mm.
For Example: To find out how big an image will be with a 1.4" superwide lens and a 15' projection distance you would
multiply 15 x 1.378 and divide by 1.4 and you would get a projection image that is 14.76' wide on the longest side of the slide rectangle.
With the widest focal length lenses commonly available you can get roughly a foot of image size for every foot of distance (so approximately
a 10' image for a 10' throw)
