Posted by David Graham on February 10, 2014 at 2:03 AM
Back in the mid to late 60s there was available for SLRs with interchangeable focusing screens ( I used Exaktas) a unique frosted glass screen composed of a checker-board pattern. The " black" grid squares on the near surface were offset very slightly from the plane of optimal focus toward the eye, and the "red" grid squares on the far surface were offset an equally tiny amount to the far side of the plane of optimal focus.
When you were close to focus you saw (for example) the near set of squares in perfect focus against the other set of squares out of focus. When you were in perfect focus the grid disappeared because both sets of squares were equally barely out of focus. it worked like a charm! That interchangeable pentaprism bearing that unique screen was stolen in the late 80s and I never got it replaced. It was rather pricy, I couldn't remember its name, and no one seemed to remember it.. Are you familiar with this kind of focusing screen? I'd be mightily obliged if you'd remind me of its name and if I could find a source.
Hi David - I never heard of this before - but I just saw something like this on Ebay. I'm out of the country with limited Net ability, so can't give you a link. I bet you can find it, though -
Sandy
Discussion
2 repliesWhen you were close to focus you saw (for example) the near set of squares in perfect focus against the other set of squares out of focus. When you were in perfect focus the grid disappeared because both sets of squares were equally barely out of focus. it worked like a charm! That interchangeable pentaprism bearing that unique screen was stolen in the late 80s and I never got it replaced. It was rather pricy, I couldn't remember its name, and no one seemed to remember it.. Are you familiar with this kind of focusing screen? I'd be mightily obliged if you'd remind me of its name and if I could find a source.
Dave Graham
East River, SD
Sandy
Sandy