Copal #

[Chris Autio]

What is copal? If it refers to diameter of lens plate hole, I have for my Toyo a 40mm as well as a wooden plate that gives it a 32 mm hole. 

[dan_fromm2]

Copal is a make of shutter.  Copal shutters conform to the Compur/Copal standard (tube length, threading front and rear, rear tube outer diameter).  To learn more about the standards, please see https://skgrimes.com/products/shutters/

[Chris Autio]

Thank you. Here is what is listed for lensplate hole for #0, 1, 3 and 3s. 

34.6 mm

41.6 mm

65 mm

64.1 mm

 So it does seem to correlate with lensplate hole. For my Toyo, I can only use #0

[Dustin McAmera]

So that's a 2x3 camera?

I have a pdf of a brochure for Fujinon lenses, which is more relaxed about the Copal sizes. It just says 35, 42 and 66mm.

My Fujinon is in a Seiko #1 shutter, which is a little bigger than a Copal 1, and needs a 48mm hole. There's also a Seiko #0, which is supposed to be about the same as the Copal 0. I don't know if there are larger sizes of Seiko.

[AJG]

4 hours ago, Chris Autio said:

Thank you. Here is what is listed for lensplate hole for #0, 1, 3 and 3s. 

34.6 mm

41.6 mm

65 mm

64.1 mm

 So it does seem to correlate with lensplate hole. For my Toyo, I can only use #0

Or you can have the hole enlarged to a larger size (a good machine shop can do this) if you have a lens in a larger shutter or buy another lens board with the right size hole. I have 6 lenses for my 4x5 Toyo cameras and have each lens mounted on its own board for convenience and preservation of the threads on the lens and shutter.

[Chris Autio]

Thank you. Here is what is listed for lensplate hole for #1,2,3 and 3s. 

34.6 mm

41.6 mm

65 mm

64.1 mm

[Chris Autio]

AJG, very good to know. Eyeing a Rodenstock 150 lens because my shutter on my Caltar 135 quit working on 1/4,1/2 and 1 sec. My recessed board on my 75 mm lens makes it very difficult to change shutter etc. I believe I can cut up 4.25” square plates for camera from masonite. (Which I have done for a fabulous ebay purchase of a 150 lens for my Beseler)

[AJG]

Or you can buy them--eBay starts at around $27 for Toyo Field Camera lens boards.  Your time and money, of course.  If you do make them make sure that you paint the inside flat black to minimize flare.

[rodeo_joe1]

To complicate things; some lenses require that the mounting ring be recessed into the rear of the lensboard. Not all camera boards come with a rebated hole to allow this. 

Those lenses with a steeply conical rear section might foul against the mounting ring if it sits proud of the plate. 

Obviously, a precision assembly like a lens can't tolerate a change in distance between the front and rear sections - some are even supplied with a measured spacer shim to adjust this. So if the rear section of the lens collides with the shutter mounting ring before it's fully seated into the shutter, then the IQ will suffer. 

I talk from experience, where one lens I have needs its mounting hole rebating. 

What I'm saying is, that just having a straight hole bored out in a mounting plate might not be sufficient. It might also require rebating (or countersinking), with a consequent complication and added expense in machining the hole. 

Edited November 30, 2022 by rodeo_joe1

[bob_eskridge]

In the past, when I ran into the problem of the hole being bored out without the rebate I just turned the mounting ring (which was flat on the back side) around.

[rodeo_joe1]

5 minutes ago, bob_eskridge said:

In the past, when I ran into the problem of the hole being bored out without the rebate I just turned the mounting ring (which was flat on the back side) around.

How does that help? The ring is just as thick one way up as the other, and the lens initially collides with the inner diameter of the ring. Doesn't matter if the rest of the surface is flat or rounded.

It needs a rebate to take it level with the rear mating-face of the shutter.

[Dustin McAmera]

I opened up the hole in a board without much difficulty or fancy tools. This one is aluminium, maybe 3mm thick. It's for my Calumet CC401 monorail (  https://www.flickr.com/photos/century_graphic/52390812125/ ). The mounting ring has a rebate like Joe describes. The board already had a hole of some size, so I couldn't use compasses to mark the new hole out. So I measured the mounting ring and cut a card disc of the right size, and centred it on the board, nudging it until it was equidistant from all four corners. Then I held it firmly and drew round it. Then I put the board in a vice, and used a half-round file to enlarge the hole toward the new line. When it was close, I switched to emery paper wrapped round a short length of dowel. Once it got very close to the line, I held the mounting ring up to the hole, to judge where I needed to do more, and slowed down. I was impressed with the neat look of the finished hole. On its own, the shutter body is loose in the hole, but it sits perfectly firmly once the ring is set in the hole and tightened.

 

[rodeo_joe1]

 

21 hours ago, Dustin McAmera said:

The board already had a hole of some size, so I couldn't use compasses to mark the new hole out.

There are tools called 'cone-cutters' (or stepped cone-cutters) that are designed specifically to open up existing holes. A bit expensive to buy for a one-off job, but just sayin'. 

And I must say that you're a bit brave trusting that Century Graphic to a Benbo-style tripod Dustin. Not that it won't take the weight, but one slip with the 'undo' lever and you've got a drunken spider rapidly heading for the ground. 

[Dustin McAmera]

That's not the Century Graphic: 'century_graphic' was previously my Flickr username (and it sticks as your url, even if you change your screen name). The camera in the picture is my Calumet CC401. It's true I don't use the Benbo often enough, and I need to take a moment every session to re-learn the way of adjusting it without collapsing it.

It's not the camera I would choose for the great outdoors; too big and too heavy, it doesn't sit comfortably on my shoulder, and I don't need big movements. The Century Graphic is actually pretty good outdoors. The body is 'mahoganite' - a thermoset resin, so it's light, and it folds up small so I can put a limited kit in a small rucksack, and use it on my light tripod.

The Calumet's the only 4x5-inch I have. It cost me 38 quid, plus picking it up: that's why I have it. I then bought the tripod for it, again chosen because it was cheap, and some film holders. The lens cost more than all those put together.

I have a stepped hole-cutter somewhere, but not for lensboard-hole sizes. I also don't have a drill-press to hold it steady.

[rodeo_joe1]

On 12/1/2022 at 12:40 PM, Dustin McAmera said:

That's not the Century Graphic: 'century_graphic' was previously my Flickr username (and it sticks as your url, even if you change your screen name). The camera in the picture is my Calumet CC401.

Yes, I thought it wasn't any Century Graphic I'd ever seen, but not being able to name the camera, I thought I'd 'go with the flow'. 

38 quid was about what I paid for my used MPP mkvi in 1971 or thereabouts. It needed work, but was still a bargain, and even came with a (slightly scuffed) 135mm Schneider Xenar and rotating-back conversion.

Other lenses were later added, and in total cost many times that amount. 

WRT the Benbo; I wouldn't be without mine. It's just so versatile. But not my first choice as an LF camera platform. 

[mpressionz]

First time I’d ever seen one of these, live and in working order… on a tripod! This camera travels with Lyle Lovett. 

[David Lindquist]

On 3/10/2023 at 1:08 PM, mpressionz said:

First time I’d ever seen one of these, live and in working order… on a tripod! This camera travels with Lyle Lovett. 

I don't think that's the original shutter, doesn't look like it has an aperture scale for the 265 mm converted focal length. On a related note, wonder when Schneider started offering their lenses in Copal shutters. Copal shutters are not listed on a January 1968 price list. In fall of 1972 I bought a new 121 mm Super Angulon that was in a Copal shutter. 

Per its serial number, the lens shown here would have been made between November 1968 and July 1970 (11 000 000 - 11 500 000).

David