Odd Shutter Behavior - Sinar/Rodenstock 90mm f/6.8

[corposant]

I have this wonderful lens and I'd like to start using it on a panoramic camera. The problem is the bellows won't compress enough to get my to infinity, so my first instinct was to get a recessed lens board. I bought one of the generic ones and am having the weirdest time trying to get it to work. The problem is that when I mount the lens to the board (21mm), as soon as I cock the shutter, it fires, no delay. I checked to see if I was accidentally triggering the release level, but no. I took out the little "pin" that allows a cable release to connect on the front side of the board. It's definitely not that. What could I be doing to trigger the shutter? I mounted it back on it's original board and unmounted and it behaves normally.

 

[randyB]

Pictures would be nice. The lens, front and back. The recessed board, front and back and the "pin" on the front side of the board.

 

[corposant]

Here you go. I showed the area of the lens that would be interacting with the board.

 

[Dan Daniel]

Sometimes cocking a shutter will move the release lever. Maybe cocking is moving the tip of the release lever into the recess wall and preventing it from holding? If so, you could grind back the end of the lever a bit?

 

[corposant]

Sometimes cocking a shutter will move the release lever. Maybe cocking is moving the tip of the release lever into the recess wall and preventing it from holding? If so, you could grind back the end of the lever a bit?

Thanks for responding. I checked this and the release lever is far enough above the wall of the board so that it can move (and release) freely.

 

[randyB]

When the lens is mounted in the recessed board how much room is around the lens? Does the tripping lever touch the wall of the recess? Does your lens have the locating screw on the back, can't tell what with the retaining ring covering the area where the screw would be. If it does have the locating screw and you mount the lens and tighten the ring it could distort/distress the shutter housing enough to trip the shutter when you attempt to cock the shutter. If the locating screw is not there then something else is causing the malfunction.

 

[OAPOli]

Another possibility is that the wall of the board is preventing the cocking lever to latch?

 

[corposant]

Sometimes cocking a shutter will move the release lever. Maybe cocking is moving the tip of the release lever into the recess wall and preventing it from holding? If so, you could grind back the end of the lever a bit?

When the lens is mounted in the recessed board how much room is around the lens? Does the tripping lever touch the wall of the recess? Does your lens have the locating screw on the back, can't tell what with the retaining ring covering the area where the screw would be. If it does have the locating screw and you mount the lens and tighten the ring it could distort/distress the shutter housing enough to trip the shutter when you attempt to cock the shutter. If the locating screw is not there then something else is causing the malfunction.

Another possibility is that the wall of the board is preventing the cocking lever to latch?

So in the light of day I was re-mounting the lens to get a better picture of the shutter release and after rotating the lens loosely in the board without the retaining ring attached I can see that the wall of the board nudges the release lever JUST enough to trigger the shutter. Now...for a person who is not that handy, what's the best way to file down or bend the release lever to prevent this from happening?

 

[OAPOli]

I think it would be wiser to modify the lens board. Locate where the lever is catching and file a slot through the wall?

 

[MARTIE]

I think it would be wiser to modify the lens board. Locate where the lever is catching and file a slot through the wall?

I agree about tackling the lensboard.
Is a 21mm sunken lensboard necessary to register infinity focus?

 

[corposant]

I think it would be wiser to modify the lens board. Locate where the lever is catching and file a slot through the wall?

Wouldn't that create a possibility of a light leak? How would I seal the area around where the level is passing through the slot?

I agree about tackling the lensboard.
Is a 21mm sunken lensboard necessary to register infinity focus?

I was thinking about trying a 12mm lens board, but before buying more stuff I would like to see if I can make this work.

 

[blee1996]

Bend the tip of shutter release lever by 90 degree, using two pliers and very carefully. You are going to use the shutter release socket anyway right, so no big deal that the shutter release lever is bent. It can be restored later.

 

[MARTIE]

Wouldn't that create a possibility of a light leak? How would I seal the area around where the level is passing through the slot?

I was thinking about trying a 12mm lens board, but before buying more stuff I would like to see if I can make this work.

If a 12mm is enough, it would make it much easier/comfortable/convenient to operate the lens.

You could save the 21mm for a 65mm or 75mm lens!

Personally, there's no way I'd mangle a perfectly working shutter for a lensboard issue.

 

[OAPOli]

@corposant My bad; yes filing through the wall will cause light ingress. Maybe with a dremel disc you could make a partial cut? Or get a board with a larger opening.

If you want to modify the lever I would at least remove it from the shutter first. These often sit on a tiny pivot which could yield before the lever itself.

 

[Doremus Scudder]

If you always plan on using a cable release, I would look at filing the lever down to eliminate the contact. Or you could modify the hole in the lensboard slightly so that you can mount the lens a tiny bit to one side, thus relieving the contact between lever and wall of the recess. Don't file a hole through the side of the recess if you choose to go that route.

Doremus