S.K. Grimes - Standard Mounting of Lens Shutters to Lensboards (Lensboard Hole Sizes)

S.K. GRIMES
Services for the Large Format Photographer

Shutters require right sized holes in their lensboard

It is often expected that lenses, as supplied by the manufacturer and fitted to stock shutters will be mounted to the view camera lensboard locally by the photographer.
Accordingly, a lensboard with the right sized hole is needed to fit the lens to the camera. There is a confusing nomenclature of boards, hole sizes, and terminology which frequently results in misunderstanding and delay in getting to photography.

MILLIMETERS	#0	#1	#3	#00**
A (Hole Dia.)	34.7	41.8	65.0	26.6
B (Thread Dia.)	32.5	39	62	25.5
C (Lock pin)*	17.8	22.0	39.2	13.8
Thinnest board	0.83	1.2	1.2	1.1
Thickest board	3.75	3.75	8.75	2.7

*The"locking pin" feature is not used in normal mounting. It's a small diameter screw projecting from the back of the shutter. New shutters are supplied without this feature and it can be safely removed from other shutters. Fitting a shutter to a lensboard without either removing the screw or boring the mating hole can damage the shutter and/or the lensboard. **#00 is an obsolete size no longer available new.

Scroll down to see more about factors affecting the hole size.
My charge to fit a standard shutter to lensboard is $25.00 - $30.00

The picture shows a lens with shutter as delivered new from the camera dealer. It is comprised of the lens, the shutter, and the threaded retainer.

A The lens is made up of the front and rear element groups which screw easily into the shutter. Sometimes there are spacers on the front or back groups. Some lenses, such as this one require the back element to be unscrewed in order to fit the entire assembly to a lensboard.

Almost all new lenses are supplied with Copal brand shutters which are available in three sizes (with some variations) known as #0, #1, and #3. Shown is a standard type Copal #0 shutter.

The retainer is supplied with new shutters and acts as a nut to secure the shutter and its lens to the lensboard. It's commonly missing on used shutters. Other shutters, especially older ones, have oddball and other mounting rings. The important point for new shutters, like this one, is that the hole size in the lensboard is determined by the diameter of the shoulder of the retainer ("A") and not the thread size of the shutter ("B").

Lensboards are proprietary to the camera manufacturer and can be wood, metal, or plastic. There is a great variety and little standardization between manufacturers. Reproduction lensboards are available for older/obsolete cameras. It's inexpensive to bore a right sized hole in a new lensboard or enlarge a hole in a used lensboard. It's more difficult to fabricate a reducing adapter to fit a smaller shutter to an already too large hole. A plain through hole can be used if the board is within the thin/thick specifications in the table above; otherwise the board can be shimmed or counterbored from behind. This ensures that the shutter will tighten onto the lensboard and the back element will screw against the shutter shoulder rather than the retainer, in the case of too thick a lensboard.

Sometimes the best thing is to just ship me the lens/shutter and lensboard. We routinely bore lensboards and mount lenses, ensuring that all details are OK so as to have the right result without a lot of hassle. Shutter mounting with a retaining ring is $25.00 and $30.00 for a flange mounting plus return shipping .

You can contact me via phone or E-mail -- The E-Mail link at the bottom of this page will summon your own blank E-mail automatically addressed to me for your convenience.)

Direct E-mail link: SK Grimes
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or
VOICE: 401-762-0857
FAX: 401-762-0847

E-Mail: skgrimes@skgrimes.com
Copyright © 2001, SK Grimes

The picture shows a lens with shutter as delivered new from the camera dealer. It is comprised of the lens, the shutter, and the threaded retainer.
A The lens is made up of the front and rear element groups which screw easily into the shutter. Sometimes there are spacers on the front or back groups. Some lenses, such as this one require the back element to be unscrewed in order to fit the entire assembly to a lensboard.
Almost all new lenses are supplied with Copal brand shutters which are available in three sizes (with some variations) known as #0, #1, and #3. Shown is a standard type Copal #0 shutter.
The retainer is supplied with new shutters and acts as a nut to secure the shutter and its lens to the lensboard. It's commonly missing on used shutters. Other shutters, especially older ones, have oddball and other mounting rings. The important point for new shutters, like this one, is that the hole size in the lensboard is determined by the diameter of the shoulder of the retainer ("A") and not the thread size of the shutter ("B").
Lensboards are proprietary to the camera manufacturer and can be wood, metal, or plastic. There is a great variety and little standardization between manufacturers. Reproduction lensboards are available for older/obsolete cameras. It's inexpensive to bore a right sized hole in a new lensboard or enlarge a hole in a used lensboard. It's more difficult to fabricate a reducing adapter to fit a smaller shutter to an already too large hole. A plain through hole can be used if the board is within the thin/thick specifications in the table above; otherwise the board can be shimmed or counterbored from behind. This ensures that the shutter will tighten onto the lensboard and the back element will screw against the shutter shoulder rather than the retainer, in the case of too thick a lensboard.