Question: How do I...troubleshoot my webcam's focus?

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Bonnieralston asked on March 31, 2019 23:11
78 views | 0 answers | #18916


Not sure exactly what happened, but the webcam no longer provides a clear image. Regardless of how I adjust the stage to bring the slide into focus, the image is blurry.



1 Comments

Which webcam are you using?

If you're using one of the USB webcams (basic or upgrade), you might want to check that everything is still level-- nothing is pulling up off the foam tape (if you used foam tape) and that the lens is still centered over the sensor. If you need to replace the foam tape that centers the lens over the sensor, I actually prefer to wrap them together with a small piece of gaff or electrical tape.

For both of the webcams, the focal distance is in the neighborhood of 1/4" from the lens to the top of the slide (though there are slight differences between models, so YMMV).

The brightness and angle of the light can also make a big difference-- focus for the light in one position/angle might be sightly different than the focus for the light in a different angle.

Are you using a cover slip on your slide? If you're focusing on something that's got a little depth to it, you might only be able to focus on an edge.

Keep in mind that your field of view is about a millimeter wide, so if you're in the middle of an object that is bigger than that, you'll see a shadow unless the object is transparent enough to let light pass through.

When I'm in workshops, I try to encourage folks to start with the slide very close to their lens (as in, almost touching, and then to slowly bring things up, instead of starting high and coming down. It sounds like you had some success before, so this might not be your issue).

If youe rubberbands are getting a little loose, you might want to add some more or swap them out for new ones: if the elasticity starts to go, then you might get a very subtle sag on the platform.

Hope some of this is helpful! If none of these seem to be issues you're having, share some photos and we can try to help troubleshoot a little more!

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