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Currently using a throwaway webcam to view backyard bird activity connected to a Raspberry PI3 using MotionEyeOS. The RPI3 is outside, as is the camera.

Question is... Is there a simple/cheap means to create a lens which would allow this, or any, webcam to zoom in say to a fixed point with a magnification of 3-5-10X? ie, the feeding area. Wish to view closer up what is happening about 15-20 ft (up to 6 meters) distant from the camera.

Repositioning the current webcam is not feasible.

If a simple field glass/telescopic lens solution is even possible then links to sites which might be relevant would be appreciated.

The Raspberry PI3 streams from outside and generates enough heat that it will probably survive some cold nights with its simple housing. The web cam is wired to the RPI3, but options are limited by what the RPI3 supports and the webcam needs to be cheap in the event it freezes and dies. Fancy web cam solutions won't work and are not supported by the RPI3 anyway.

Tried SE.Photography first, but if there is a more appropriate forum or forums I will redirect.

  • You can get cheap add-on lenses for camera phones. Maybe they would work. Don't know what the quality is like. – vclaw Jul 18 '16 at 11:48
  • @vclaw that would be nice but I can't visualise a way in which they'd mount to a webcam as phones have flat backs. I've got a macro lens that relies on a flat smooth surface – Chris H Jul 19 '16 at 7:20
  • How cold are your nights? I'd expect webcams to work in a freezer for example. The biggest issue would be condensation. – Chris H Jul 19 '16 at 7:21
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It would be possible to use any small telescope or monocular or one side of binocular. You figure out a way to allow mount one of these devices to your webcam. The lens of the webcam is positioned to peer into the telescope/binocular. This method is called "afocal". The name comes from the fact that the image forming rays from the telescope/binocular exit the instrument's eyepiece as parallel rays. You focus the telescope/binocular for your eyes targeting a distant subject. The webcam is focused for infinity. The webcam lens does all the necessary focusing, the telescope/binocular does the magnifying.

Try it, you'll like this lash-up!

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    "digiscoping" is another related term that may be helpful – Chris H Jul 19 '16 at 7:15
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I've had success in the past with CCTV lenses mounted to webcams in place of their original lenses. The tricky part is securely and accurately mounting the two together - we had a part machined for one application, but I've also used the front of a dead CCTV camera and lots of glue.

The positioning has to be correct in three dimensions to work well. As webcam sensors are so small, a 50-75mm lens is usually telephoto.

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