Any experience with the Pacific Optical 6" f2.8?

[John Schneider]

I recently pulled one of these from a KS-87 aerial camera cone that had been sitting for years. Unlike their monster version of the 75 Biogon, this one is actually a reasonable size. So, I'm pondering the additional work to remove the shutter mechanism and shooting with it. But before I do any more to a potential doorstop I wanted to see if any one had any experience with this lens. It makes what I believe is a 4.5" square image, so it should cover 4x5. But since it contains an aperture, I don't know if it covers wide open, or with how much additional coverage. Anybody here use one of these things?

[Dan Fromm]

John, according to my USAF data sheets the lens covers 4.5" x 4.5" wide open. If you do the arithmetic, you'll see that this means covers 4x5.

There are at least two designs with slightly different back focuses. The second type was used on the KS-87. AWAR wide open on Plus-X, 38 lp/mm. It beats 20 in the corners.

The data sheets also report on the 150/2.8 Xenotar. No AWAR given; wide open it is much sharper centrally than the PO and no less sharp at the edges.

[John Schneider]

Dan, thanks so much for the info; you seem to be the expert on aerial lenses. Since I have a surplus barrel 150 Xenotar in good shape (from the eBay seller who seems to have dozens and dozens of them) and a shutter from a 240 convertible Symmar, I'll CLA the Copal and get an aperture scale made and then sell the PO on eBay, thus saving me lots of work and effort. Many thanks!