Sinar Norma 4x5 ground glass/fresnel arrangement

[LF_rookie_to_be]

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:

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The camera back I have:

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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?

[Ari]

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.

[Jim Noel]

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.

[LF_rookie_to_be]

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.

[LF_rookie_to_be]

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.

[Frank Petronio]

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.

[LF_rookie_to_be]

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.

[Frank Petronio]

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!

[Richard Wasserman]

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........

[Frank Petronio]

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 ;-)

[LF_rookie_to_be]

Hmmm, this definitely warrants a precise test.

[Frank Petronio]

Since you are new to large format, I wouldn't get too worried about it. It is highly unlikely your camera is out of adjustment since it was probably used professionally for years. If you notice problems then of course you may need help but I would go ahead and make some fun photos to start with and not get too worked up about it.

Sinar itself will still work on Normas, as well as Sinar-Bron in New Jersey. But I prefer Bob Watkins at precisioncameraworks.com in Chicago, he used to work for Sinar. Note that some parts are very expensive, the replacement bubble levels are $140. Bob actually made duplicates that are still expensive but not nearly as much. I have purchased second Normas for parts since they are relatively inexpensive and you can resell the leftovers to recoup your expense. And the truth is, you really don't need bubble levels at all, most of the time I don't even watch them and a $6 pocket level will accomplish the same task should you need one.

A forum member, Phillip Morgan, has created this valuable guide: http://www.philipmorgan.net/the-sinar-norma-cla-guide/ THANK YOU!!!

[Ivan J. Eberle]

The Norma I owned had a plain GG with a clip-in, clip-out Fresnel in the frame with knobs that made it simple to do. Would that I kept it as it also fit my Meridian. Anyhow, the Norma also has a Graflok/Universal back, and it should swap with almost any other back, including a later Sinar model (which the OP's may turn out to be).

[Michael Whyte-Venables]

The Fresnel that was supplied for use with the Norma is inserted BETWEEN the GG and the objective lens. The optical fresnel surface is in contact with the ground surface of the GG, and the GG is therefore moved slightly further from the frame of the back by the fitting of the fresnel; the fresnel compensates for this. To this end the edges of the fresnel are milled thinner to make a rebate like that depicted in the diagram at the beginning of the thread. I have one. That all having been said I don't like it! I think it makes fine focussing more difficult, and it is a fag to fit and remove (being a screwdriver and v. fiddly screw job). The later design, as in the photograph is probably easier to add or remove but I don't have one of these.