[Walt Fricke]

Thanks, Spencer
Wireless, happily, is not something which is needed or particularly useful in the application I have in mind. If one were a shop owner, maybe the ability to have the picture show up on a big screen somewhere would be useful - some of the wheel alignment systems shops use benefit from something like this - no wires running around, big display the technician can see while adjusting the toe, etc. So I'll look on that as a sort of minus.

And good info on the focal length - sounds like the one I just ordered will have a problem that way, as 30mm is 3cm.

With these small cameras, what affects the focal length? Is this about the same as depth of field we used to think about with pre-digital cameras? Wider aperture = greater depth of field? Are these probe cameras charge coupled devices? Is it an optical lens over them which affects depth of field? Is the view angle related to "focus distance"?

Assuming some standardization of the probe camera enclosure diameter, there is a three mirror assortment out there for USD 10. Looks good in the seller pictures, anyway.

Shop guys worry about mirrors or other attachments falling off. If replacement probe cables (I think they tend to have a standard plug)are fairly inexpensive, one might think of gluing or otherwise affixing mirror attachments to probes, so you would change the probe based on what mirror angle was needed. Shops often worry about things we home brew guys don't - costing money and losing customers and reputation means a lot, while as a hobbyist we can just curse and spend more time. On this deal I have to think like a shop owner.