Replacing a lost iris on B&L 15" EFL Portrait Plastigmat

Just sharing my fix to replace an iris on a Bausch&Lomb Portrait Plastigmat.

One more working orphan to play with now :)

http://amedeusphoto.zenfolio.com/blo...d-some-history

The approach is similar to what I've done with the Ross Landscape lens few weeks back.

Cheers,

Rudi, so it does make sense to keep all of the parts we have. Nice job!!

Good to see it back in use, they're a favorite soft focus of mine.

Just for historic interest, my 15" Plastigmat has the glass modifier in the front and my 18" does not. No serial numbers for you. Out at work.

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Originally Posted by Jim Galli

Just for historic interest, my 15" Plastigmat has the glass modifier in the front and my 18" does not. No serial numbers for you. Out at work.

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Thanks Jim, I find that the Portrait Plastigmat lenses have a relative short production life as far as I can tell based on serial numbers I own/seen.

Cheers

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Originally Posted by Amedeus

Thanks Jim, I find that the Portrait Plastigmat lenses have a relative short production life as far as I can tell based on serial numbers I own/seen.

Cheers

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My 18-inch Portrait Plastigmat has the front element, a very weak meniscus single element, but I've seen others without.

Let's see, the Portrait Plastigmat, the Portrait Unar, the Sigmar... what other soft-ish portrait lenses did B&L have out around that time?

Series A Portrait with diffusing adjustment (Petzval)
Portrait Unar with diffusing adjustment (Anastigmat iirc)
Portrait Plastigmat, single achromat and achromat+meniscus version, diffusion controlled by aperture
Sigmar, triplet, like the Wollensak Varium, softish lens, not necessarily SF ...

I believe that's all ...

Cheers,

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Originally Posted by Mark Sawyer

My 18-inch Portrait Plastigmat has the front element, a very weak meniscus single element, but I've seen others without.

Let's see, the Portrait Plastigmat, the Portrait Unar, the Sigmar... what other soft-ish portrait lenses did B&L have out around that time?

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Quote:

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Originally Posted by Amedeus

Series A Portrait with diffusing adjustment (Petzval)
Portrait Unar with diffusing adjustment (Anastigmat iirc)
Portrait Plastigmat, single achromat and achromat+meniscus version, diffusion controlled by aperture
Sigmar, triplet, like the Wollensak Varium, softish lens, not necessarily SF ...

I believe that's all ...

Cheers,

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Out of curiosity, do you, like me, consider the diffusing on petzvals as perhaps a marketing scheme? I've not seen any real diffusion on these things.

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Originally Posted by Jim Galli

Out of curiosity, do you, like me, consider the diffusing on petzvals as perhaps a marketing scheme? I've not seen any real diffusion on these things.

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I equally consider it marketing, move the lens, which defocusses and then adjust focus again to be mostly sharp again. Although on paper the spherical aberrations are different, the change is so small I can't pick up on it.

YMMV,

Quote:

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Originally Posted by Amedeus

I equally consider it marketing, move the lens, which defocusses and then adjust focus again to be mostly sharp again. Although on paper the spherical aberrations are different, the change is so small I can't pick up on it.

YMMV,

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The Vade Mecum speculates the Portrait 1-A diffusion adjustment was mainly effective for close-up portraits:

The separation of the rear glasses was adjustable to control softness, and this may be most useful in close-up as it increases the depth and eveness of definition.

I have Mr. Galli"s 9" 1-A (intended for 4x5) ... I have only shot it close-up on 8x10 for flowers and still life. When diffused and re-focused the effect is very subtle.

Thanks Jim for your input and observation.

I have the Portrait 3-A mounted and I'll check the close-up scenario next time I'm working with the camera.

Cheers,

Quote:

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Originally Posted by Jim Graves

The Vade Mecum speculates the Portrait 1-A diffusion adjustment was mainly effective for close-up portraits:

The separation of the rear glasses was adjustable to control softness, and this may be most useful in close-up as it increases the depth and eveness of definition.

I have Mr. Galli"s 9" 1-A (intended for 4x5) ... I have only shot it close-up on 8x10 for flowers and still life. When diffused and re-focused the effect is very subtle.

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