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Thread: Sinar Norma 4x5 ground glass/fresnel arrangement

  1. #1

    Sinar Norma 4x5 ground glass/fresnel arrangement

    Recently I acquired a Sinar Norma 4x5 camera in great condition. Looking at it, I noticed the arrangement of ground glass and fresnel on the camera back may be different than the description in the manual, but am not entirely sure whether it actually is. This is the diagram from the manual, with my presumed (possibly wrong!) arrangement in red:

    Click image for larger version. 

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    The camera back I have:

    Click image for larger version. 

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    Two pictures on the left show the fresnel side, as viewed when focusing, and the last image on the right shows the side to the bellows. Is this back correctly assembled?

  2. #2
    Unwitting Thread Killer Ari's Avatar
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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Some camera makers put the GG inside the fresnel, and a few put it on the outside.
    You should follow the manufacturer's recommendation to start with, then check focus on GG vs focus on film plane.
    Norma users can chime in and confirm your set-up.

  3. #3

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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    The Norma originally came w/o a Fresnel. One was available which clipped on to the small projections at either side of the round glass and had the rings toward the ground glass. Therefore I believe that yours is incorrect. I suggest you check it by focusing carefully wide open on a target like a newspaper at about 10 feet. Make a negative and check it for sharpness.

  4. #4

    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Jim,

    The camera came with both Fidelity Elite 4x5 double holders and Toyo 9x12 double holders. I carefully inspected the position of the matt side of the GG (closest to the lens) as well as of a film sheet in Fidelity holders and it looks to my eyes the GG is slightly closer to the lens than film. I'll try the film test as soon as I obtain a lensboard and a lens.

  5. #5

    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    From the manual (the text that accompanies the above illustration):

    "... (Fresnel lenses)... are mounted between the seating area for the focusing screen and the screen itself, with the smooth side of the lens outwards, so that the grooved and matte surfaces face each other."

    I take it this means the fresnel's non-grooved side is facing the lens.

  6. #6

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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    I don't know what that manual is referring to but the way you have it in the photos is perfect and you are good to go.

    The normal Sinar configuration is to have a simple plain ground glass resting on the cast/milled surfaces of the back, held by clips. The Fresnel is an accessory in a metal frame that is placed between the ground glass and the photographer's eyes. It easily clips in an out, that is why it has those vertical tabs (so you can handle it). This way you have a choice and can do the fine, critical focusing on the more telling and reliable ground glass. Don't try to focus critically on the Fresnel.

    The downside is that the Sinar Fresnel often gets scratched up from this cycling, so many other brands of view cameras have a Fresnel mounted on the inside of the camera between the ground glass and lens for the convenience of the photographer. This can work nicely but there is a compensation that needs to be made since the image is no longer focusing exactly where you think it is, so you want to do a test or trust that it is in factory spec (98% of the time they are). When some amateur simply slaps a Fresnel in without checking - then the fun begins and everything is slightly out of focus until you experiment with shims or send the camera off to a good technician. None of this is a concern with any Sinar. In fact you can mount any thickness of a plain ground glass onto the back as a replacement since the rests for the glass are precisely milled and don't need shims.

    Perhaps the manual you are looking at is showing how you can attach a bellows to the back to use as a view hood? Or it is not a manual to a Sinar? Is it a manual to a Fresnel Optics screen or something else? I've never seen that in a Sinar and I've had a dozen-plus pass through my hands.

  7. #7

    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Frank,

    This is the manual I have: http://www.cameraeccentric.com/html/info/sinar_1.html
    But your answer pretty much sums it up, thanks.

  8. #8

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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Ah that is very old and before they made the Fresnel that came with your camera. It sounds like it was an upgrade at the time, not a stock part in the base model.

    I assume that if your camera didn't come with the internal Fresnel then you have nothing to worry about.

    Once you get going with it, it never hurts to do a newspaper test. Lay a newspaper down on a table and shoot it from 45 degrees. Focus on a particular line of text and shoot near wide open. The film should be in focus there too. Expect a very slight error due to film flexing, etc. Usually f/11 will cure that!

  9. #9

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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Just to roil the waters—I just bought another Norma and it has a fresnel mounted in the manner shown in LF Rookie's OP. It is between the groundglass and the lens, with the smooth side facing the lens. I of course don't know if this is an original set-up, but judging by appearances it has been used this way for a long time. I need to add though that the Norma back doesn't have 2 surfaces—1 for the fresnel, and 1 for the GG. It simply has one milled surface and clips to hold everything in place, so I am wondering about the voracity of the drawing. Or was there more than 1 version? I think the moral of this story is: Test, Test, Test........
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  10. #10

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    Re: Sinar Norma 4x5 ground glass/fresnel arrangement

    Wasn't it in production from the early 50s to early 70s? I've seen black ones, green ones, different knobs and bits... so it evolved.

    It is fun to see a typewritten manual ;-)

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