Optical Mouse Navigation

[phrontist]

Originally Posted by Alan Anderson

No, as I said before, it's not a focus problem.

The "telephoto mouse" we constructed has a bit more than a centimeter of variation in range where it will still track the carpet if appropriately illuminated. But it won't track it consistently if the distance isn't kept absolutely constant.

I'm sorry, I don't know that much about optics, please explain how this is not a focus problem. Logically, if you move the mouse up and down it will be tracking larger and smaller patches of carpet. Why would a sudden jump in registered distance occur if it were getting a clear image? If it didn't have a large enough depth of field, it would make sense if a sudden jump occured, for that would indicate the feild of view had been passed and the sensor was no longer in focus. Please clarify.