Concerning the 6x7 TTL prism finder, David Mann wrote: > The plastic thumbwheel that sits under its shutter speed dial, is that > meant to be a completely separate part, or is it supposed to stay > attached to the prism assembly? [Snip....]
> Also the power switch doesn't actually lock into the on or off positions, > it just springs back to the middle. A different prism I played with does > the same. Is that normal? Hi Dave, Yes, it's a completely separate part, and it can be purchased new for a ridiculous price ($30 US or thereabouts, IIRC). You're right -- it's easy to lose. Bill Robb told me a while back that this "TTL ring" was included with the original TTL prism finder when purchased new, but that sellers of used TTL prism finders often do not include this helpful little thumbwheel. I believe I read on the Greenspun archive that a cut-up piece of plastic 35mm film canister works just as well. That ON/OFF switch is meant to be a momentary contact switch. The fact that it rests in the middle position between ON and OFF is perfectly normal. By the way, Dave, I was hoping you might consider gathering and reporting a little bit of useful information. If you happen to remove your TTL prism finder cover to reveal the circuit board underneath, I wonder if you might possibly be able to measure the resistances that the three potentiometers on the circuit board are set to. I'd be especially interested in what readings you get with the prism finder removed from the camera body. I've measured the values for mine, and I believe these are appropriate when one is using a brighter-than-normal screen. I'm wondering what the values are, typically, for a prism finder calibrated for a normal screen. Well, must get some lunch now. Cheers! 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 .
