View Full Version : Stupid Question - Removing Lens

27-Jun-2012, 03:48
So, it is with some embarrassment that I ask this, but I'm having a lot of trouble removing my 90mm from its lens board.

I have been able to unscrew the back side of the lens, which I'd assumed would've let me be able to remove the lens, as with my others, however there's a retaining ring that I can't remove? Well in fact there are two, the inner most one unscrews, but because of the outer one, it cannot be removed.

Have photos:


I anyone could offer assistance, it would be great.


27-Jun-2012, 04:15
Is that top photo with the rear lens group removed? It looks like the elements were removed but not the barrel. It should all just unscrew. Then you'll be able to get at the retainer ring with a lens wrench.
Is this your first time with LF lenses or have you done this before?

27-Jun-2012, 04:25
The rear elements are removed in the top photo, however I can't really get the barrel off? Unless it's just tightened to an incredible level? Didn't want to force it too much to check...

It is my first time trying to remove the lens or any lens in LF, I've never had the need in the past.

27-Jun-2012, 05:35
Can you post a picture of what you managed to remove? Is there any lettering on that rear piece? If there is some lettering, then it is most certainly a part of the rear lens group and should be unscrewed.
Also look for any set screws or anything. If there are none then its probably just screwed on crazy tight. The previous owner might have used a strap wrench or something to tighten it.
Can you remove the front group? That might give a clue as to how the lens is mounted. It should just screw straight off. Grab the barrel where the Rodenstock lettering is and unscrew. You should end up with the whole front group and the shutter on the lens board. Take a close look and there might be some other screw or retainer ring hiding somewhere, but I doubt it.

Dan Fromm
27-Jun-2012, 05:38
The lens is in shutter. A retaining ring is clearly visible in the first image. Use a spanner to unscrew it and pull the shutter with front element out of the board.

27-Jun-2012, 05:44
No need to remove the elements (glass only) on any lens I'm familiar with. The rear barrel (with the lens elements inside) is what must come off so you can get to the retaining ring that holds the shutter and front barrel in place. Sounds like that rear barrel has been graphically over tightened. That rear group and barrel actually bypasses the retaining ring to mount inside the rear of the shutter. It seems that that is where the over-tightening has occurred. The retaining ring serves only to engage the outer threads on the rear of the shutter assembly and hold the whole unit in place in the lens board.

Put the elements back in carefully along with their retaining ring, then visit your hardware or auto parts store for a strap wrench in a small enough diameter to fit around the rear barrel. That will give you much more torque than your hand can ever develop and it will put even pressure all around the barrel without scratching or other damage.

Grasp the lens board or even put it in a vise and then use the strap wrench to rotate the whole rear group counter clockwise. Once that is off, its quite simple to remove the actual retaining ring to dismount the shutter.

27-Jun-2012, 05:46

Are you referring to the section closer to the board? It does unscrew somewhat, however because of the ring of the same size that is attached to the lens, I can't remove it?

I'll try and get more photos tomorrow.

27-Jun-2012, 06:01
The small ring with the notches on the back is the retainer ring. Normally you should be able to just unscrew that with a lens spanner wrench and the shutter with front group will drop out of the front of the lens board. That big rear "ring" is most probably the left overs of the rear lens group which should have been unscrewed with the glass in it. I'm interested in seeing what you have actually removed because it seems to me like you have a bunch of loose glass elements now and the retainer ring which keeps them in the rear barrel.

Dan Fromm
27-Jun-2012, 06:29
dmb, as sumo wrote that small ring with notches is the retaining ring. It should unscrew.

E. von Hoegh
27-Jun-2012, 06:42
dmb, as sumo wrote that small ring with notches is the retaining ring. It should unscrew.

But you must first remove the threaded adapter that goes between the rear cell and the shutter.....

27-Jun-2012, 16:34
Got some additional photos, showing the rear element on and detached.

Had another look at it based on what all had said, and it's still baffling me. There doesn't appear to be anything that can be unscrewed any further than the ring with the rivets out of it, but it unscrews to a point then is faulted by the outer ring...

Thanks all

27-Jun-2012, 16:43
The ring at the rear, still attached to the shutter, is an adapter or spacer.
It's a separate item that must be removed to permit unscrewing the retaining ring (the one with the slots).

It should unscrew counter-clockwise, just like the rear cell that you already removed.

One common trick in the repair industry is to put a thin rubber sheet on the workbench, then place the open end of the spacer/adapter on it. Apply pressure from above and try to rotate the shutter assembly in the proper direction.

If that doesn't work, there's another trick that must be done carefully...

Holding the lensboard with the shutter pointed up, apply one or more ice cube(s) to the outside of the adapter ring close to but not touching the retainer ring or the shutter itself. This may shrink the adapter enough to loosen it.
Be very careful that you don't get any water in the shutter. Thoroughly dry the area before you turn it right side up.

This works really well with dry ice. Don't try that unless you know how to handle it, and have appropriate gloves and tools.

A suggestion to avoid problems...

Engage the preview lever to open the shutter blades, and open the aperture to maximum.
This will prevent damage to the blades in the event of a mishap (tool slip or whatever).

- Leigh

27-Jun-2012, 17:22

- Leigh
Just to confirm Leigh, you're referring to this ring here in red:
That needs to come off to allow the retaining ring to be removed?

If so, it's going to take a mighty amount of elbow grease!

Thanks for the extensive response though!

27-Jun-2012, 17:25
Yes. The ring that turned red is the culprit. :D

It might have been installed with some type of thread locking agent (Loctite or similar).
That would be very poor practice, but nothing's impossible.

I would suggest removing the front cell before you proceed.
It's not involved in the effort, and you run the risk of damaging it while you're working on the rear.

- Leigh

27-Jun-2012, 17:33
Yeah it looks like you just have to give it some work.
The strap wrench idea is probably the safest but it requires a strap wrench.

28-Jun-2012, 01:19
Argh... The frustration grows... I used more force than I thought it would have needed and thought I had it when something released, however that was just the front part of elements unscrewing... Now it appears I have the shutter stuck in the lens board?

28-Jun-2012, 02:07
The Copal #0 and #1 shutters have anti-rotation screws designed to prevent them from rotating in the lensboard,
which can cause the retaining ring to come loose.

Many people remove them, or fail to install them, so there's about a 50/50 chance of one being on your shutter.

If it's installed, the shutter will not rotate relative to the lensboard unless you apply enough force to sheer the screw.

- Leigh

28-Jun-2012, 02:45
The whole shutter definitely rotates in relation to the lens board, quite freely at the moment...

May have to take this to a repair place and have them pry it apart!

28-Jun-2012, 03:31
Do you have a vise or something?
Hold the shutter body secure and then grab the rear ring and turn. Alternatively hold the rear ring and turn the shutter. If you have 2 strap wrenches you should be able to get it off pretty easily...
Whatever you do don't get impatient and rush things. That usually ends in a bad way I find ;)

28-Jun-2012, 05:11
That adapter ring is way too thin for a vise.
It would get crushed or distorted if you applied enough force to prevent it from rotating.

The only commonly-available tool that might work is a strap wrench, as mentioned above.

The other option would be a custom-made collet with a threaded plug inserted in the adapter.

- Leigh

28-Jun-2012, 05:28
Heat can be your friend here. About 5 years ago I started heating stubborn lens rings with great success. I have an old platen style print dryer onto which I set the shutter and let it heat up for 15 to 30 min or so. It will be too hot to touch. I use Playtex-style gloves. They have some insulation to keep from getting burned and the cheaper knock offs are made of a very 'grippy' rubber. Grab and twist.

28-Jun-2012, 09:51

My earlier advice regarding the strap wrench should be limited to the now red ring at the rear of the assembly. I would NEVER apply a strap wrench to the shutter assembly because you would run the extreme risk of dislodging any or all of the projecting bits, like the cocking lever, the preview lever, the PC post and the aperture marker. Goodbye shutter in that case.

If you need to get a better grip on the shutter, far better to head for the grocery store to find one of those rubber pads that are sold to hold reluctant jar lids while you turn them. That won't provide torque so much as grip which is what you need on the front end.

You need a third hand, so as I mentioned before, clamp the lens board in a vise, use the rubber gripper on the shutter and the strap wrench (get one with the leather or rubberized strap, not metal) on the back red thing and then go to work. Once that rear ring is off, the actual retaining ring will be a piece of cake.

28-Jun-2012, 13:47
My earlier advice regarding the strap wrench should be limited to the now red ring at the rear of the assembly. I would NEVER apply a strap wrench to the shutter assembly...
That's kinda obvious, I think.

- Leigh

E. von Hoegh
28-Jun-2012, 14:08
One way to get a good grip on that ring without distorting it (very important) is to superglue it to s flat bar of metal. Once the glue sets, use the bar as a wrench to unscrew it. You may have a butterknife that will work. Remove the ring from the "wrench" with acetone.

28-Jun-2012, 14:32
Agreed, it should be quite obvious, but another member a few posts back suggested using two, so I thought I'd better jump back in.

E. von Hoegh
28-Jun-2012, 14:36
Agreed, it should be quite obvious, but another member a few posts back suggested using two, so I thought I'd better jump back in.

I'd advise against the vice, too.

28-Jun-2012, 17:51
Just out of curiosity, why do you want to remove it?

28-Jun-2012, 18:11
Just out of curiosity, why do you want to remove it?
There's an unmounted lens visible in the first photo.

I'm assuming he wants to dismount this one so he can mount the other one on this lensboard.

Plaubel lensboards are not the most common in the world. It took me quite a while to build up a collection of them.

- Leigh

28-Jun-2012, 22:14
Just out of curiosity, why do you want to remove it?
Wanting to mount to a different camera.

Will try and track down a strap wrench methinks...

Frank Petronio
28-Jun-2012, 22:57
If you can't find a small strap wrench, sometimes a rubber stopper can fit into the spacer and give you the friction and leverage to twist. They sell these in those parts bins at Lowes, Home Depot, etc. try a couple sizes.

29-Jun-2012, 00:57
One other trick is to stick the whole assembly in your FREEZER for a few hours. The flange may shrink at a different rate than the shutter threads, allowing your to turn it. (It won't hurt the shutter or lenses.)

29-Jun-2012, 05:32
eeeerrrrr some things are best left alone! if you have a camera to use it on then do that. why risk f'ing up a good lens. if you break it it may not be usable after.

another option is to cut off the retaining ring (if it is fact a retaining ring) go slowly and if you have patience you will be able to get it cut while still not damaging the threads beyond use.

and/or you can cut the flange off making it easier to cut the ring off.

anyway you do it. let us know what happens.

29-Jun-2012, 16:26
I got it!

After resigning myself to the fact that I was going to have to take it to a repair shop and pay to have it removed safely, i decided to dremel down the newly purchased strap wrench to make it more effective, then a large amount of straining ended with it coming loose...

Such a relief!

Thanks for all the ideas everyone!

29-Jun-2012, 16:35
Wonderful. Congratulations!

- Leigh

30-Jun-2012, 07:08
Good news!