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Re: Process Camera.

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  • eric evans
    Hi Rob, Thanks, and like I said, something new every day . I m 79, and still learning. The question is academic, as I have no intention of using the camera,
    Message 1 of 16 , Apr 8, 2009
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      Hi Rob,
      Thanks, and like I said, "something new every day". I'm 79, and still learning. The question is academic, as I have no intention of using the camera, even if I knew how, but the more you learn, the more you know, and I am grateful for your input; dating-wise, it's back to the drawing board on this one, but I have enough from Sandy to believe it is about 1914 or earlier.
      Thanks and Regards,
      Eric.
      In Sheffield, Yorkshire, where it is the most brilliant day so far; hope it stays like this for the Easter weekend.


      --- In woodandbrass@yahoogroups.com, Rob McElroy <idag@...> wrote:
      >
      > Sandy, Eric, et al.,
      >
      > Process lenses with a slot for Waterhouse stops were made continuously
      > through the 1980s and probably beyond, so you can't use the presence
      > of the slot on the lens as any kind of dating mechanism for the camera.
      >
      > Fewer and fewer printers experimented with changing the shape of their
      > half-tone dots as the 20th century progressed, especially after color
      > printing became the norm, instead of the exception, in the 1960s and
      > 70s but the slot still existed on the lenses for those printers that
      > wanted the option to do so. The slot performs double duty, and can
      > hold a filter, diaphragm plate, or both together. The slot was also
      > made so that the diaphragm plate could be tilted, which also altered
      > the shape of the half tone dot. I have several Apo-Nikkor lenses made
      > in the 1980s, and they were all originally sold with a set of aperture/
      > diaphragm plates (specific to each lens) where the user could "for
      > special effects, widen and modify the shape of the hole until the
      > desired shape is achieved."
      >
      > Cheers,
      > Rob McElroy
      > Buffalo, NY
      >
      >
      > On Apr 8, 2009, at 6:51 AM, eric evans wrote:
      >
      > > Thanks again, Sandy. It's beginning to look more and more like pre-
      > > WW1, if that type of lens was becoming obsolete by the 20s.
      >
      >
      > On Apr 8, 2009, at 6:27 AM, apbarrie wrote:
      >
      > > Hi,
      > >
      > > the slot in the lens new is additional data... (not in the original
      > > story)
      > >
      > > it was not for the waterhouse type aperture as most photographers
      > > would know it.
      > >
      > > it was for "Screening" Apertures. the lens was put to full diaphragm
      > > aperture and this special aperture dropped in that slot.
      > >
      > > what is did was to 'modify' the shape of the dot formed on the
      > > printing plate. They were experimenting with non circular dots, then
      > > when they were experimenting in colour printing., where as today,
      > > almost everything, used circular dots.
      > >
      > > (Agfa's famous 'Crystal' raster was an unusual non regular screen
      > > pattern, but still used circular dots..)
      > >
      > > This was almost totally given up by the 1920's. so that sort of
      > > dates the lens...
      > >
      > > you may want to post this for others, just in case.
      > >
      > > Regards
      > >
      > > Sandy
      >
    • apbarrie
      Hi, I was going on what I have in My Penrose annuals. Regards Sandy Barrie. Honorary Life Member, Australian Institute of Professional Photography. Valuer
      Message 2 of 16 , Apr 8, 2009
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        Hi,

        I was going on what I have in My Penrose annuals.

        Regards

        Sandy Barrie.

        Honorary Life Member, Australian Institute of Professional Photography.
        Valuer Appointed, Federal Government Dept. Arts Sport & Tourism.





        On 09/04/2009, at 2:20 AM, Rob McElroy wrote:

        Sandy, Eric, et al.,


        Process lenses with a slot for Waterhouse stops were made continuously through the 1980s and probably beyond, so you can't use the presence of the slot on the lens as any kind of dating mechanism for the camera.

        Fewer and fewer printers experimented with changing the shape of their half-tone dots as the 20th century progressed, especially after color printing became the norm, instead of the exception, in the 1960s and 70s but the slot still existed on the lenses for those printers that wanted the option to do so.  The slot performs double duty, and can hold a filter, diaphragm plate, or both together.  The slot was also made so that the diaphragm plate could be tilted, which also altered the shape of the half tone dot.  I have several Apo-Nikkor lenses made in the 1980s, and they were all originally sold with a set of aperture/diaphragm plates (specific to each lens) where the user could "for special effects, widen and modify the shape of the hole until the desired shape is achieved."

        Cheers,
        Rob McElroy
        Buffalo, NY


        On Apr 8, 2009, at 6:51 AM, eric evans wrote:

        Thanks again, Sandy. It's beginning to look more and more like pre-WW1, if that type of lens was becoming obsolete by the 20s.


        On Apr 8, 2009, at 6:27 AM, apbarrie wrote:

        Hi,

        the slot in the lens new is additional data... (not in the original story)

        it was not for the waterhouse type aperture as most photographers would know it.

        it was for "Screening" Apertures. the lens was put to full diaphragm aperture and this special aperture dropped in that slot.

        what is did was to 'modify' the shape of the dot formed on the printing plate. They were experimenting with non circular dots, then when they were experimenting in colour printing., where as today, almost everything, used circular dots. 

        (Agfa's famous 'Crystal' raster was an unusual non regular screen pattern, but still used circular dots..)

        This was almost totally given up by the 1920's. so that sort of dates the lens...

        you may want to post this for others, just in case.

        Regards

        Sandy


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