In article <31F83EDD.56C5@pacbell.net>, varm@pacbell.net says...

>I'm trying to find a good source for information on measuring resolution
>on a video system (ie what test patterns are available, and how to use
>them). I'm also looking for a source for information on the various
>types of lens attachments. For instance, how does a close-up lens set
>affect the system in terms of the camera being able to focus correctly
>and are there other types of lens that can do the same thing but offer
>better performance.

No help on the first, but on the second, Sigma (for their 90mm macro
lens for 35mm cameras) and Nikon (3T and 4T - get the 4T) make excellent
2-element achromats in 52mm threaded mounts which are very sharp, and
camera focus ability is unaffected (and they give highest magnification
at the long end of the zoom range - a real advantage for some subjects!).
Hope This Helps