The Logitech C920 is a lovely little webcam, and having the MP4 conversion on the onboard processor means you can use it with gutless hardware. I got mine as a cast-off from Jason at Wildlife Gadgetman and wanted to use it for video-conferencing, what with the coronavirus lockdown and all that.
Trouble is the damn thing is short-sighted. It seems to be a common problem with the C920, and the autofocus is ratty. Sometimes it would work, sometimes not.
I am short-sighted too, so a temporary fix to get it to focus on distant objects is to Sellotape one lens my glasses over the front, but it’s not a good look. AF was still ratty. Poor distant focus is a common complaint with the C920. This fellow shows you how to take it to bits
but unlike him, my fault was the little piece of metal had become loose and was fouling the movement of the lens.
Extracting the washer from the lens, using the notches to pass the castellations on the lens mount let me isolate it
I did consider leaving it off
but figured I’d get flare from reflections from the plastic cover in front so I used thick superglue, carefully to avoid getting it on the lens. Four dabs at the corners sorted it.
Job done, sorted. This doesn’t seem the only way for these cameras to misbehave on focus, and unfortunately you can’t see the errant washer because of the baffle on the plastic cover. But you have to take it to bits if your problem is the focus is off as the one in the video. There’s a neater way to do the glasses thing with an eyepiece adapter lens as in this video, which doesn’t entail taking it to pieces, but that wasn’t the problem for me.