Compur #2 Shutter Stuck on Mounting Flange Zeiss Tessar 135mm f3.5

[baronkatz]

Hi Everyone,

I ended up buying a war time Zeiss Tessar 135 3.5 that's coated since I couldn't afford to buy a Xenotar or Planar and wanted a fast lens for shallow DOF and Bokeh for portraits. It seems like LF lens manufacturers don't really care about speed these days and most of the really fast glass is vintage or even antique. As such, the shutter that the Tessar came on seems to be older than the lens itself and is unique in that it has a 50mm screw mount. Due to this I can't just remount the lens on a new shutter.

The shutter is stuck on the mounting flange which is screwed into the lens board. Unfortunately, I cannot seem to twist it off. I've tried everything from rubber jar openers, to heat from a blow drier, to oil and silicone lubricants, to naptha. Nothing has helped. Someone had mentioned there might be a set screw holding it in place in the threads, but I don't see one. I'm guessing that the previous owner must have used threadlock or some sort of glue on the threads. I could cut the lens board off but that won't solve the problem of getting the mounting flange off so that I can mount it on my Polaroid 110B 4x5 conversion.

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[EdSawyer]

what does the back of the board look like?

[baronkatz]

what does the back of the board look like?

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[Bob Salomon]

If they used a thread locking material then that usually loosens with heat. Try your hair dryer on high for more time.

[EdSawyer]

what's the little bolt/dot at about 10 oclock in the picture? it looks like a nicely made board, by whomever made it. could try a strap wrench around the outside of the shutter body with the board clamped in a vise, and some heat-gunning. It must come apart somehow.

[baronkatz]

what's the little bolt/dot at about 10 oclock in the picture? it looks like a nicely made board, by whomever made it. could try a strap wrench around the outside of the shutter body with the board clamped in a vise, and some heat-gunning. It must come apart somehow.

The little dot is a screw that goes from the mounting flange to the board. The previous owner made the board - it is nice which is why I don't want to ruin it if I don't need to.

[Jac@stafford.net]

The little dot is a screw that goes from the mounting flange to the board. The previous owner made the board - it is nice which is why I don't want to ruin it if I don't need to.

Drill out the screw.

[baronkatz]

Drill out the screw.

I could do that - but as I mentioned before - unfortunately I will still have to take it off the mounting flange and the lens board seems to be easier to grab than the mounting flange in terms of twisting off.

[Bob Salomon]

I could do that - but as I mentioned before - unfortunately I will still have to take it off the mounting flange and the lens board seems to be easier to grab than the mounting flange in terms of twisting off.

Get a Rodenstock/Linos lens wrench to do it properly!

[baronkatz]

Get a Rodenstock/Linos lens wrench to do it properly!

That only works with retaining rings - not mounting flanges which are screwed onto the board vs. being twisted on like with a retaining ring.

[Bob Salomon]

That only works with retaining rings - not mounting flanges which are screwed onto the board vs. being twisted on like with a retaining ring.

OK, some people also have called the rings a flange.

[baronkatz]

OK, some people also have called the rings a flange.

According to SK Grimes (http://www.skgrimes.com/products/mounting-flanges) here's the difference:

"A mounting flange is a metal threaded ring with several holes bored into it which is used to allow a shutter or lens to be installed onto a lensboard. It is permanently attached to the front of a lensboard with screws. Flanges are frequently missing from their lenses. If you have extra flanges, you can fit them to several different lensboards and can then easily switch a lens amongst different cameras.

A retainer is similar to a flange except that it has no holes bored into it and is used like a “nut” in a “nut and bolt”; it holds the lens or shutter onto the board more or less permanently by screwing on from the back. Retainers often require a special tool to install or remove, so lenses mounted with them are not as easily interchanged as those using flanges."

[Bob Salomon]

According to SK Grimes (http://www.skgrimes.com/products/mounting-flanges) here's the difference:

"A mounting flange is a metal threaded ring with several holes bored into it which is used to allow a shutter or lens to be installed onto a lensboard. It is permanently attached to the front of a lensboard with screws. Flanges are frequently missing from their lenses. If you have extra flanges, you can fit them to several different lensboards and can then easily switch a lens amongst different cameras.

A retainer is similar to a flange except that it has no holes bored into it and is used like a “nut” in a “nut and bolt”; it holds the lens or shutter onto the board more or less permanently by screwing on from the back. Retainers often require a special tool to install or remove, so lenses mounted with them are not as easily interchanged as those using flanges."

That really isn’t news. From 1986 till 2/2015 I was the product and sales manager for Rodenstock, Linhof and Wista. We supplied every size of rings and flanges up to 90mm.

However, during that period customers and users frequently used the terms interchangeably.

[baronkatz]

That really isn’t news. From 1986 till 2/2015 I was the product and sales manager for Rodenstock, Linhof and Wista. We supplied every size of rings and flanges up to 90mm.

However, during that period customers and users frequently used the terms interchangeably.

That's awesome. I'm sure you're more knowledgeable than me. I've been shooting mostly 35mm and MF until I got my first 4x5 a couple of years ago. I bought this lens as I wanted something fast and unfortunately most modern lenses are slow and don't have the bokeh or shallow DOF I'm looking for - I also shoot a lot handheld with slow panchromatic B+W film (APX 25 + 50) and Velvia 50, mostly street shooting but some indoor portraits with natural light. So I could use the extra stop or two that these lenses offer wide open on top of that.

Someone mentioned a set screw - but I don't see a set screw anywhere. I think it's more likely the aluminum threads on the shutter fused with the brass mounting flange? Anyway - I've tried all the above methods - I guess I could go to a Machine shop and see if someone can use a huge spanner wrench with a towel wrapped around the shutter to prevent damage... just would rather do it at home if I can and not have to go to extremes.

[Jac@stafford.net]

I could do that - but as I mentioned before - unfortunately I will still have to take it off the mounting flange and the lens board seems to be easier to grab than the mounting flange in terms of twisting off.

That screw might be going through the board, and through the flange and into the lens. It serves to keep the lens from moving while changing shutter speed, setting aperture or to make it impossible to remove the lens. :)

As for penetrating threads stuck due to dissimilar metals, Kroil or PB Blaster plus patience works well. WD 40 is worthless for that.

Best of luck!

[Bob Salomon]

That's awesome. I'm sure you're more knowledgeable than me. I've been shooting mostly 35mm and MF until I got my first 4x5 a couple of years ago. I bought this lens as I wanted something fast and unfortunately most modern lenses are slow and don't have the bokeh or shallow DOF I'm looking for - I also shoot a lot handheld with slow panchromatic B+W film (APX 25 + 50) and Velvia 50, mostly street shooting but some indoor portraits with natural light. So I could use the extra stop or two that these lenses offer wide open on top of that.

Someone mentioned a set screw - but I don't see a set screw anywhere. I think it's more likely the aluminum threads on the shutter fused with the brass mounting flange? Anyway - I've tried all the above methods - I guess I could go to a Machine shop and see if someone can use a huge spanner wrench with a towel wrapped around the shutter to prevent damage... just would rather do it at home if I can and not have to go to extremes.
A good machinist can easily slit the flange so it can be removed and make a new fing or flange to replace it. I doubt that an aluminum ring would fuse with brass as dissimilar metals are self lubricating. And on a lens that old it probably isn’t an aluminum flange.
I would also doubt that a screw is holding it in place. If it is it would have to be on the edge of the flange. Very doubtful.

But before you invest too much you should check how well, if at all, that lens wide open or one stop down can fully cover 45. And bear in mind, if important to you, large format lenses for 45 usually perform optimally around f22. Not wide open.
And, as you stop down, the area of coverage increases. Minimal coverage is always wide open. The circle of coverage also increases at closer distances then infinity.

[baronkatz]

That screw might be going through the board, and through the flange and into the lens. It serves to keep the lens from moving while changing shutter speed, setting aperture or to make it impossible to remove the lens. :)

As for penetrating threads stuck due to dissimilar metals, Kroil or PB Blaster plus patience works well. WD 40 is worthless for that.

Best of luck!

The three screws that are there are only on the mounting flange - they do not touch the shutter. I tried an oiler as well as liquid wrench silicon lubricant as well as naptha which I heard might help. None of those things have. I don't want to buy any more stuff for this as nothing is penetrating into it.


A good machinist can easily slit the flange so it can be removed and make a new fing or flange to replace it. I doubt that an aluminum ring would fuse with brass as dissimilar metals are self lubricating. And on a lens that old it probably isn’t an aluminum flange.
I would also doubt that a screw is holding it in place. If it is it would have to be on the edge of the flange. Very doubtful.

But before you invest too much you should check how well, if at all, that lens wide open or one stop down can fully cover 45. And bear in mind, if important to you, large format lenses for 45 usually perform optimally around f22. Not wide open.
And, as you stop down, the area of coverage increases. Minimal coverage is always wide open. The circle of coverage also increases at closer distances then infinity.

I have had someone try this lens on their 4x5 and it definitely covers, wide open too but barely. At infinity it might vignette, but I'm mostly shooting at portrait distances. I know that LF lenses usually perform better at a smaller apertures but anything smaller f4.5 is usually not shallow enough of a DOF for me, at least not on 4x5. I like it wide open for the bokeh and shallow DOF. My camera doesn't have any movements to compensate for this, and even if it did, I would shoot wide open or close to it since I am shooting handheld with my 110B 4x5 conversion with slow film and therefore would need it wide open either way. If I could afford it I would get a Planar 135 3.5 or a Xenotar 150 2.8 or Komura 152 2.8... Once I get my Graflex I will be shooting mostly with fast projector lenses, many of which are incredibly sharp wide open.

[Jac@stafford.net]

Well, it appears that you are fully aware of all solutions, so your last resort is to adapt the lens board to your camera even if it means cutting your board smaller, leaving the flange in place and mounting it to a board that fits. In my view, you are on your own now.
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