Question: Which No IR 12mm lens should I get for 640x480 webcam?

jevs is asking a question about lego-spectrometer
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by jevs | November 16, 2019 05:03 | #21503

I want to buy a no IR lens for my webcam, but I am not sure what value lens to get?

The lens that came on the webcam says f=3.85mm.

I am not sure what the best size is to get for a spectrometer project though


there may be some answers for you in the research notes produced by @Stoft and @Warren on the topic of camera's native resolution and optics as a guide look at the the plab spectromer V3.0 specifications, camera used especially the 8, 16 megapixel and higher 8 bit cameras as SBW does not use the available native pixel width in its calculations the f3.5 refers to the light gathering properties i.e. an f2.0 lens is much better than a n f3.5 depending on which light levels you are operating in. plse check the research notes for more in depth info.


Apparently a capital F and a lowercase f mean something different. I changed my post to a lowercase f=3.85mm. Apparently f is focal length and F is the F-stop, "speed" or how light sensitive the lens is.

My lens only has the little f designation. So I guess my question is better stated to ask what focal length would be best to get??

The only thing I found reference to so far in looking through what you recommended is that they used an f=8mm lens for the high rez camera testing. I cannot tell if the one linked has IR filter or not, or if 8mm is optimal for the lower res webcams.

I am still digging around though...

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