Does anyone know the construction of Berthiot perigraphe lenses? I found yesterday here at Rio de Janeiro, two of them: a 90mm F14 and a 120mm F14 too. They are equipped with wheel-stops and I'm wondering if they have the same construction of old protars (four elements, two groups) or are even simpler. I saw some of these lenses being sold at e-bay. Any information would be appreciated.

-- Jose Luiz Vasconcellos (guacira@openlink.com.br), June 14, 2000

Answers

I have one (120mm/f:14), purchased recently from JCR cameras in the UK before he started putting them up on eBay, and I think it's a neat lens. I just had Steve Grimes mount mine in an Ilex 3 shutter. It's extremely compact, covers 8x10 at f:44 (the smallest aperture with the wheelstops--an Ilex 3 only stops down to f:32 with this lens, but one does gain a slightly wider aperture at the other end) with a bit of movement and about 1-1/2 stops of falloff from center to edge, and produces a nearly rectilinear image. I'm not sure whether the construction is two or four elements, but there are two groups.

-- David Goldfarb (dgoldfarb@barnard.edu), June 14, 2000.

these lens cover 1050 the old model closed at 56 and the new at 44 so the 90 cover 5*7 and the 120 cover 8*10 it also exist in 60, 75, 135), 150,180,200, 250 the 90 and 120 are the most findable of the series.

-- nze christian (christian_nze@hotmail.com), June 14, 2000.

The Perigraphe is similar to the Goerz Dagor in construction. It's a six element lens made up of two symmetrical cemented triplet groups. The nominal coverage angle is stated as 65 degrees, but like the Dagor it increases greatly with stopping down.

-- Pete Andrews (p.l.andrews@bham.ac.uk), June 15, 2000.

If you're curious to see how the mounting job came out, here are two images.

-- David Goldfarb (dgoldfarb@barnard.edu), June 19, 2000.