[LargeFormat] Bausch and Lomb Portrait Lens

[Les Newcomer]

"...Next in order comes the Bausch & Lomb Plastigmat, a lens of our own
creations. All lenses of the Zeiss Series are unsymmetrical with the
exception of the Zeiss Convertible, and it is to meet the demand of the
symmetrical Anastigmat at a less cost thatn the Zeiss  Convertible which
promted us to place this lens on the market. It's merit is testified to by
the fact of its increasing sale and popularity. it has a speed of f/6.8,
ample for all outdoor work except the speediest, even illumination over a
much larger area than it is rated for, and great covering capacity."

"Souvenir of the Conference of Photographic Dealers" held at the work of the
Bausch & Lomb Otical co. Rochester, NY february, 20-22., 1905

the lens fits with a general patent granted to ed bausch filed in 1900 where
he puts for elements into play.  in volving a miniscus w/ref index of 1.51,
a double concave r1.56 ,plano-concave r1.58 ,double convex r. 1.60.  the
second one he reverses the order of the 1.58 and the 1.56.

the third version he tried to cement the elements together. A Codicil was
put forthwith when it was learned that this was essentially a protar. The
codicill specifies the order of the refractive indicies so as not to
interfere with Zeiss's patent.

The name Plastigmat, or Unar, another lens based on this patent is not
listed.

Now after I typed all that, I found in "Handbook of Photography c1939, B&L
made a Plastigmat Portrait lens.  Which has only a minicus front element and
an achromat rear cell (plano-concave cemented to a convex)

It has a field of view of 40 degrees, speed of f5.6 and were made in focal
lengths ranging from 9-18.

> From: Clive Warren <cocam@blueyonder.co.uk>
> Reply-To: largeformat@f32.net
> Date: Sat, 13 Apr 2002 03:28:56 +0100
> To: largeformat@f32.net
> Subject: [LargeFormat] Bausch and Lomb Portrait Lens
> 
> Buried under mounds of paperwork here and haven't even read my Email!
> Have surfaced only because a rather interesting Bausch and Lomb 15"
> f5.6 E.F. Plastigmat Portrait Lens was given to me by the postman
> today. Some people watch the tv - for me it's lenses ;-)
> 
> Usual question - anyone know anything about these lenses? It is about
> 6 1/2" long and 4" across at the business end. My guess is that it
> dates from the 20's and that it is soft until stopped down. Not
> enough light here to check it out. Hope to be using it tomorrow if
> all goes well.
> 
> It is currently sitting on a Korona 8x10 field camera with a 4x5 back
> - if anyone has a Korona 5x7 or 8x10 back for the 8x10 that they
> would be willing to part with then please let me know as it would
> probably make me a happy chap.
> 
> Cheers,
> Clive
> 
> _______________________________________________
> LargeFormat mailing list
> LargeFormat@f32.net
> http://www.pairlist.net/mailman/listinfo/largeformat