Master Technika why the shims beneath the ground glass?

[Jordan]

So why did Linhof complicate things by having the ground glass need shims for focus alignment? Why wouldn't a ledge on the frame suffice? I would like to maybe add a brighter screen and know if my alignment is correct without the need to send it away to the service place. I've changed out my ground glass on other cameras plenty without ever having to consider this. Linhof clearly makes a beautiful camera, but a bit particular.

[Brian Ellis]

I don't know why they didn't design the camera differently than they did. But when I replaced the original screen on a Master Technika with a Maxwell screen Maxwell sent replacement shims to ensure a correct fit with the new screen. And when I replaced the original screen on a Tech V with a BosScreen the new screen was designed to use the existing shims. The only time I would think you'd have a problem is if you just buy a generic screen without getting either new shims for the new screen like Maxwell or a screen made for your model camera like BosScreen and I don't think I'd want to use a screen made by someone who didn't do one or the other.

[Jack Dahlgren]

shims generally allow adjustment if needed. So if the back is too far away they could use a different thickness of shim rather than thinning the back. Shims are kind of old-school.

[William Whitaker]

Sticking my neck out on this one, but Technikas are/were designed to use cammed lenses as well. The shims may possibly be so the ground glass focus can be matched to the cam focus.

[Peter K]

Sticking my neck out on this one, but Technikas are/were designed to use cammed lenses as well. The shims may possibly be so the ground glass focus can be matched to the cam focus.
A shim between shutter and lensboard does this job better. But the gg should be aligned so the focus plane is the same as the film surface.

[Frank Petronio]

They standardized the cams from the V onwards, so once the cams were a fixed item I guess they needed a way to adjust the ground glass.

Seeing there have been so many different fresnel options, it's one of those things you'd always want to check with a used Technika. Since they are valuable cameras, letting Marflex give it a look over always seemed worth the cost. Martin is very honest and straight-forward.

Since I don't like fresnels or trust (my use of) large-format rangefinders, I prefer the way Sinar does their back - you can slip any old glass on top of a referenced surface. Use an external fresnel if you like, but don't leave the thing mounted to your camera to muck things up and get in the way of actually seeing the image.

Or on my Crown you simply never mess with it, something breaks you just get another $200 camera lol.

Wista, Arca, the Chinese, all tie you into their fresnel choices unless you want to monkey around retrofitting a Maxwell or something else, and then you still need to check distances and test, so the Linhof isn't any worse in that regard. I bet a lot of people have slightly off distances but because they stop down to >f/16 they never notice.

[Bob Salomon]

Unless you have a Boss screen where the image forming plane is between two sheets of glass or have some other exotic screen where the imaging forming plane is not on the front facing surface then you have no worry about the shims.

The ground side of the gg faces the lens and is placed directly onto the shims. The thickness is immaterial as the critical surface is on the shims.

So there is no need to send your camera out to change the gg since adjusting the shims is not necessary to change the focusing screen. Unless someone was tampering with the back.

So just like Frank's camera, you can put any gg on the shims and the gg will be in the proper location. In other words, the shims were set at the factory to the proper distance and the user should have no reason to set them any differently. They are what assure not only proper focus on the film when using the gg but also with the rangefinder when you use that as well.

Why the shims? Some people have multiple Technika cameras so from the V on all Technika 45 cameras had a zeroed gg. This was done by adjusting the shim settings on all V and Master Technika Classic models so they can share the same cam if that cam's lens was used on another body.

[Neal Chaves]

There's a bit more to it than that. Every late Tecknika camera has the focusing track set up on a "hard stop" so that the combination of the view on the shimmed ground glass and the "infinity" position of the focus track and RF match up with the film plane. This is unlike the Crown and Speed Graphics which can be cammed and set up on "hard stops" but come from the factory with cams that often set up on "soft stops". If unqualified wingnuts have messed with either camera, all bets for accurate focus either on GG or by RF are off.

[Bob Salomon]

There's a bit more to it than that. Every late Tecknika camera has the focusing track set up on a "hard stop" so that the combination of the view on the shimmed ground glass and the "infinity" position of the focus track and RF match up with the film plane. This is unlike the Crown and Speed Graphics which can be cammed and set up on "hard stops" but come from the factory with cams that often set up on "soft stops". If unqualified wingnuts have messed with either camera, all bets for accurate focus either on GG or by RF are off.

Neal,

The Technika IV and later cameras accommodate a series of Folding Infinity Stops. One for each lens cammed. These, as well as the focusing scale for each lens, are installed at the time the lens is cammed. A Master Technika is only shipped from the factory with a Folding Infinity Stop installed if the lens was ordered for the camera at the same time as the camera. If the lens is ordered after buying the camera then the stop is installed either by the Linhof service center in your country or by the user in conjuction with an installation kit that includes a target that you have to place on a window.

[Neal Chaves]

No, those are bed stops for the lenses on the camera bed. There are hard stops for the focus track located at the front bottom of the track. They were adjusted for the standard spec for infinity and then pinned there. These stops come to bear on the front cover casting. Don't ever take those stops off (They are pinned on!) if you don't understand the mechanism.

[Bob Salomon]

No, those are bed stops for the lenses on the camera bed. There are hard stops for the focus track located at the front bottom of the track. They were adjusted for the standard spec for infinity and then pinned there. These stops come to bear on the front cover casting. Don't ever take those stops off (They are pinned on!) if you don't understand the mechanism.

Are you talking about the stops for the three position tracks? The first one (closest to the body housing allows the track to be in its normal position, pushed back into the body for wide angle use or extended to make a two extension track for longer lenses. The second one allows the final section of track to extend to make a triple extension rail.

The Modern Technika: Master Technika Classic, Master Technika 2000 (discontinued) and the Master Technika 3000 4x5 cameras have notches on the bottom side of the rail track on the right side of the camera (looking at it from the back. These notches are roughly where the Infinty Stops will be placed on the tracks. The rear most notch 0 for a normal lens with the upper track in the normal position. Notches 1 and 2 for wide angle lenses when the red track lock is pushed down and the top track is pushed into the camera body. Notches 4 and 0 for longer then normal lenses when the blue track lock is pushed down and the upper track is extended.

The only mechanism under the track bed that can be manipulated by the user is the focusing cam. Other parts and settings are factory adjusted and should not be tapered with. As a rule of thumb on a Technika. If you need a tool to adjust it. DON'T!

[dofmaster]

Hmm... On my MT Classic focusing screen consist of two pieces - ground glass and plastic fresnel. I beleive they're old type (look dim and fresnel cannot be removed without screw). Bob, it's a question to you - can you please tell correct order and position of this sandwich?
Which side GG should look onto lens - matte or polished? Where should be the fresnel - between the lens and GG (on the shims) or behind GG (facing the focusing hood)? Fresnel itself look matte from one side and engraved from other (have non-cutted edges). For me looks strange - why matte surfaces on both pieces?
I usually shoot landscapes on f22+ so focus problem is not always easy to see. But something is definetely wrong... Is there a possibility that i have combination of old Super Screen and conventional GG?

Thank in advance, Bob!

[Bob Salomon]

Hmm... On my MT Classic focusing screen consist of two pieces - ground glass and plastic fresnel. I beleive they're old type (look dim and fresnel cannot be removed without screw). Bob, it's a question to you - can you please tell correct order and position of this sandwich?
Which side GG should look onto lens - matte or polished? Where should be the fresnel - between the lens and GG (on the shims) or behind GG (facing the focusing hood)? Fresnel itself look matte from one side and engraved from other (have non-cutted edges). For me looks strange - why matte surfaces on each piece?
I usually shoot landscapes on f22 and higher so focus problem i not easy to see, but something is definetely wrong...

The ground side of the gg is placed on the shims facing the lens. It is held in place by the black gg hold down strips at either end of the gg. The hold down strips are fastened to the back with three screws
The Fresnel is placed on top of the gg with the grooved rings facing the lens. A properly attached Fresnel on a modern Linhof is held in place either by lift-up clips screwed into the middle screws on the hold down strips (this is the older system and these clips were sold as accessories complete with a longer screw to replace the middle screw on the hold down strips). The later way is a swing away chrome metal holding strip that comes attached to the middle acres on the hold down strip.
To put the Fresnel screen in place with the older system just flip up the Fresnel clips. Lay the Fresnel on the gg grooved side down and flip the clips down. If you have the current system just swing the clips to the side, lay the Fresnel in place and swing the clips back to hold the Fresnel in place. Both of these systems allow the Fresnel to be easily and quickly installed and removed, in case you don't want to use a loupe and don't want to view through the Fresnel screen.

It sounds like your Fresnel screen was not properly installed and that you need to get a pair of the swing away current clips from the Linhof distributor in your country. These are not very expensive and they are easy to install as long as you have the proper screw so you would want to order that as well. All three screws on the hold down clip are the same length with the current system. With the older system the middle screw was longer as the folding clip was thicker.

As to why both sides of your Fresnel appear matte? I think you have an enhanced focusing screen, like a Beattie, rather then a Fresnel screen. If so it is possible to get two images to focus on, one on the gg and the second of the frosted side of the Fresnel. That is not good and it should be replaced with a proper Fresnel. it also sounds like you have a very old and dirty gg. It should be cleaned with a good lens cleaning solution. If that doesn't make it brighter then a new gg is in order.

[craig nye]

If you have a way to measure the distance from a sheet of film in a film holder to the edge of the film holder accurately, this distance should be the same as the distance from the ground glass surface to the edge of the ground glass holder - if that makes sense.

If you wish to replace your GG, you can measure the distance on your old GG then install the new and check - it will be the same. Like Bob has said.

I received Tech V with no GG and missing shims, and an 'out of alignment' back - lots of "fun" getting it back in to spec (or as close as I can, until I can afford a proper service). Luckily I now have all 4 shims and my cammed lens, RF and GG are all in agreement at infinity and other measured distance settings.

[dofmaster]

Bob & Craig - many thanks! I removed fresnel screen at this time and placed GG in correct position (ground side to shims). I've also measured spacing on GG frame and Fidelity holder, now accuracy is about 0.1 millimeter (I beleive film thickness will compensate this difference) and everything should work fine.
The downside is that I need another Fresnel now... Anyway I'm going to order it's latest version. The question is - do I need to buy new GG also? Any improvements made novadays (I espesially dislike the coarse grain of my old GG)?

P.S. Can you imagine - I have shot 25 sheets of slide film on my MT during last trip. And, despite the improperly installed GG, most of them look fine. Thanks god I used wide lenses stopped down :)

[Bob Salomon]

Bob & Craig - many thanks! I removed fresnel screen at this time and placed GG in correct position (ground side to shims). I've also measured spacing on GG frame and Fidelity holder, now accuracy is about 0.1 millimeter (I beleive film thickness will compensate this difference) and everything should work fine.
The downside is that I need another Fresnel now... Anyway I'm going to order it's latest version. The question is - do I need to buy new GG also? Any improvements made novadays (I espesially dislike the coarse grain of my old GG)?

P.S. Can you imagine - I have shot 25 sheets of slide film on my MT during last trip. And, despite the improperly installed GG, most of them look fine. Thanks god I used wide lenses stopped down :)

The current gg from Linhof is much brighter then older ones. But I have no idea what gg is currently in your camera so I can't tell you anything other then it will be brighter and finer grained.

[dofmaster]

Mine have grid (black painted) and 9x12 frame line - no other marks. Corners are not cut off.