Bill Kane wrote: > I know this is a question that's never been asked before. I know to be > able to focus CLOSER to an object, you need a close up lens . . . > . . . BUT, I have a project where I need to actually be able to focus > FURTHER from the lens.
Hi Bill, One way to look at this is that you need to move your lens closer to the CCD imaging array. Before you do anything else, take a look at your lens mount on the camera. There are actually two types of mounts -- C and CS. They both use the 30mm C-thread, but IIRC, the CS mount positions the lens 5mm close to the imaging array than the C mount. Can you switch your camera between C and CS? I've got a Panasonic video camera at work that I can set either way. Switching the mount from C to CS would solve your problem, I think. Another way to look at this is that your current lens is too strong (i.e., focal length is too short), and you need to weaken the lens. Do this by placing a diverging lens in front of it. Maybe you can obtain a few cheap 2"-dia. planoconcave lenses of various focal lengths and try them out? Start with one that's maybe -1.5x to -2x times the focal length of your current lens. Vary the effective "correction" imparted by this lens by moving it closer to or further from the front of your current lens. Maybe even a pair of eyeglasses would work for a quick experiment, if you can find someone who's nearsighted and wears glasses. Hope this helps. Bill Peifer Rochester, NY - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
