GOERZ Red Dot ARTAR - Tech Data Sheet

[R Mann]

I have found a copy of this and thought it would be a good idea to post it - dates from 1964-

[Richard K.]

Saved it. Thanks very much for this information!

[Oren Grad]

Ditto - thanks!

[Dan Fromm]

Interesting.

I've been baffled by sellers' claims on eBay that a 4" Apo Artar will cover 2x3. Covering 4" seems like a real, um, stretch for a 4" process lens.

The second sheet says that lens covers 46 degrees (I calculate that means 87 mm), the fourth that it covers "2x3" at infinity. I'm more confused than ever.

Cheers,

Dan

[Steve Hamley]

Dan,

I get the same, 46 degrees for a 4" lens gives 86.2 mm of coverage, and the diagonal of a 2" x 3" rectangle is 91.5mm or roughly 5mm difference. But film is smaller than the plate size and has a rebate, so maybe it does just cover accounting for a rebate.

I've often wondered by what criteria that process lens coverage is specified. We all know that Artars will illuminate considerably more than 46 degrees, and that at least some of that seems to be usable. Since they were born as process lenses, I wonder if the coverage was determined by a distortion limit rather than a resolution limit. If the coverage was based on distortion going south for repro purposes faster than resolution, that could easily explain the discrepancy in coverage claims by general photographic users.

Cheers, Steve

[Dan Fromm]

Steve, I shoot 2x3. I've always understood 2x3 to be shorthand for 2 1/4 x 3 1/4. As it happens my roll holders' gates are roughly 56 mm x 81 mm, diagonal 98 mm. So I still don't get it.

Cheers,

Dan