Spotting scopes sold for bird watchers and rifle marksmen can be quite inexpensive compared to serious camera lenses of similar zoom capability. I knew there was a difference in the picture quality but wanted to try it first hand.
Since the picture is zoomed in so far, any physical movement is greatly magnified in the image. Which meant simply holding the webcam up against the eyepiece by hand just resulted in many blurry pictures. Taping them to each other wasn’t good enough – the small movement allowed by tape was enough to distort the picture. What I needed was a solid adapter to hold them against each other.
3D printer to the rescue!
The scope eyepiece unscrews easily, which makes for a convenient mounting point for a 3D printed bracket. The webcam is then attached to the bracket by means of a ring matching the diameter of the webcam. I didn’t want to spend too much time on fancy fastening designs on the first draft, intending to use tape. As it turned out friction was enough to hold everything together well enough for a quick experiment.
Results of the experiment: you get what you paid for. The image quality of a cheap webcam looking through a cheap scope was barely legible. I don’t intend to put more money into this investigation, so I’m unlikely to upgrade to better scopes. What I do have, though, are some better cameras which might be worth experimenting down the line.
One problem that I should have foreseen was the very incompatible fields of view of the two instruments. A webcam is designed to capture a very wide field of view, because during video chats the face is very close to the webcam. A spotting scope is just the opposite – it has a narrow field of view of a very distant object. When I put them together, what I get is the narrow scope view in the middle of a big wide field of black.