Here is a view of my "zoom" pinhole camera...lol Here we are "wide angle", or shortest focal length.

To make the "Zoom" pinhole lens I use a Mead Variable Projection Tele-extender and a T thread to EOS adapter. Normally I use this combination on my Meade LX-200 10" f10 telescope, but for the pinhole zoom lens I covered the end with aluminum foil and poked a little hole in the foil.