Which shutter for Rodenstock 90mm F6.8 Grandagon-N

mercurye · Sep 10, 2020

I purchased a Rodenstock 90mm F6.8 Grandagon-N that was attached to Copal Press Shutter 0. The shutter got sand particles in it and became unusable, so I went to purchase another Copal 0, only to see the threads don't fit (see attached photo for original Copal Press 0 (bottom left) and new Copal 0 (bottom right). It looks like it has a black piece added on the front threads. I thought the lens then was for a Copal 1, which I bought, but the front element is maybe 1mm too big to fit on the thread, and the back element fits both Copal 0s, but not the Copal 1.

My question is: was the Copal Press 0 made especially for this lens? Can I remove the black threaded piece to put on the new Copal 0? I tried before but didn't want to force it.

If anyone could help me out, I'd be very grateful!

BradS · Sep 10, 2020

I have 90mm f/6.8 Grandagon-N. Out of the original box, it came in an ordinary (not press) black Copal #0.

shutterfinger · Sep 10, 2020

That looks like an adapter on the front of the Press, its not a part of the shutter. Depending on the age of the combo it may be stuck and require some force to remove.
Use a rubber strap wrench if necessary to remove it.

voceumana · Sep 11, 2020

I have often found you can get a better grip on threaded things that are stuck by simply wrapping them with masking tape and then unscrewing them. It seems to add just enough friction to get a better grip.

Alan Edward Klein · Sep 11, 2020

Here's a wrench made for various shutters to loosen and tighten the holding ring. I use it for my Copal 0. It has three other shutter sizes as well; not sure about yours.
https://www.amazon.com/dp/B002RPFMEK/ref=pe_825000_114212990_TE_FOCE_n_id

Alan Edward Klein · Sep 11, 2020

Note that the same wrench handles four shutter sizes.

Rick A · Sep 11, 2020

That adapter on the Copal Press shutter should definitely be able to unscrew to remove. Wrap electricians tape around it several wraps, and try to unscrew by hand. If that fails, try freezing the shutter over night and try again.

xya · Sep 11, 2020

Rick A said:
That adapter on the Copal Press shutter should definitely be able to unscrew to remove. Wrap electricians tape around it several wraps, and try to unscrew by hand. If that fails, try freezing the shutter over night and try again.

I would never freeze a shutter. when you get it out of the freezer, all moisture in the air will condensate on it. and you don't know how the lubricated parts will react. they may get stuck. you could try to warm the shutter body in your hand and then press the adapter against a frozen surface for a couple of seconds. the difference in temperature might help.

Dennis-B · Sep 11, 2020

A decent spanner wrench will also work. I keep two of them with various adapters in my gear box.

shutterfinger · Sep 11, 2020

xya said:
I would never freeze a shutter.

Seal the item in a ziplok bag with as much air squeezed out as possible before putting into the freezer.
Heating your oven to its lowest temperature setting, placing the item (metal not plastic) on the center rack of the oven, close the door and then turn the oven off. Leave the item for 30 minutes then remove from the oven and unscrew the stuck part.

mercurye · Sep 14, 2020

I got it off with duct-tape wrapped around it and a rubber-strap wrench. It was on there extremely tight. Thanks everyone!

CatSplat · Sep 16, 2020

Glad to hear you got the adapter off - your 90mm is certainly an odd duck, I took a picture of the backside of the front cell on mine for comparison:

Yours is clearly machined way differently and is intended to be used with the adapter... but why, I wonder?

xya · Sep 17, 2020

I have a similar copal press shutter with a very similar adapter piece. it comes from a polaroid mp4 copy system and holds a single front lens of a 75mm optics via a ring. my adapter doesn't come off as well. maybe the shutter of your lens has already been replaced. someone had this type of shutter and adapted the front lens to his shutter...

reddesert · Sep 17, 2020

Screw the "adapter" back onto the lens cell, turn it over, and compare it to CatSplat's picture.

It might be that it's an original part of the lens cell, and it was stuck on the shutter so tight that you unscrewed it from the lens rather than unscrewing it from the shutter. There might also be a setscrew somewhere that was supposed to hold it in place (just a guess, I have no experience with this lens).

mercurye · Sep 19, 2020

Yes, I think the "adapter" is actually part of the lens. When screwed on it looks just like CatSplat's photo.

Which shutter for Rodenstock 90mm F6.8 Grandagon-N

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