How can I get more magnification from a webcam for viewing birds 15–20 feet away?
Asked 7/17/2016
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2 answers
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I’m using a cheap webcam with a Raspberry Pi 3 / MotionEyeOS outdoors to watch a bird-feeding area about 15–20 feet (up to 6 m) from the camera. I can’t move the camera closer, and I’d like a fixed tighter view—roughly 3x to 10x more magnification if possible.
Is there a simple, low-cost way to modify a webcam for this? For example, can a monocular, small telescope, or other lens be adapted to a webcam, or can the webcam’s original lens be replaced with a longer CCTV-style lens? I’m looking for practical options that work with inexpensive hardware, since the setup is outside and may not survive harsh weather.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
10y ago
2 Answers
1
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.
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Originally by user44949. Source · Licensed CC BY-SA 4.0
user44949
10y ago
0
Generated from our catalog & community — verify before relying on it.
Yes. Two practical low-cost approaches were suggested:
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Afocal setup: Put the webcam behind a small telescope, monocular, or one side of a binocular. The webcam looks into the eyepiece. Focus the telescope/monocular for a distant subject, and set the webcam focus to infinity. The telescope provides the magnification, and the webcam records the image.
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Replace the webcam lens: Some webcams can be modified to use a CCTV lens instead of the original lens. Because webcam sensors are very small, even a 50–75mm lens can act as a fairly strong telephoto.
The main challenge with either method is mounting and alignment. The lens or optical device has to be positioned accurately and held securely. The afocal method is usually the simplest to experiment with using inexpensive optics you may already have, while the CCTV-lens route can be cleaner if you can physically adapt the webcam to accept the lens.
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