lens elements placed in a Copal shutter

[Robert Vigurs]

I had a wonderful day today. Seeing that the air was still, and no haze in the air, I drove to Pescadero, up the coast and exposed six 4x5 sheets. I wished I had loaded more. There will be other days. I returned to my darkroom and developed same with HC-110, a developer I know well. All turned out well, and I look forward to printing. They are drying now. I operate on little money. My Symmar 210, my favorite, has a scratch or two, and coating problems. However, if I'm careful I can make good images. My Super-Angulon is old, and f8, but again, if I'm careful I can make good images. Here is my question. I have a good Copal 1 shutter. Since I can't afford perfect glass, I bought two sets of lens elements, Fujinon W180, and W125 from ebay, both late model. Both from Japan. Dented barrels. A few hairline scratches. Are Copal shutters all the same, as far as length between element groups? I imagine they are made to a formula so lens makers can count on this length when designing the lenses. Obviously a wafer thin shim could be placed as a spacer to extend length. Bottom line question, can I screw those elements of the 180 into the Copal 1 it was designed for, and expect clarity? Sorry to be so longwinded here. Thanks, Robert

[Kevin Crisp]

In general, the Copal shutter dimensions in the 0 and 1 sizes are standard. There are some examples of some lenses that do use thin spacers to deviate from the standard dimensions, this seems more common on wide angles in my experience taking them apart. But even then you don't see it often.

Screw the lens elements into your shutter and look at the ground glass wide open and see if it looks sharp. It probably will and you'll be fine, so long as you remember that your aperture scale is for 210mm lenses, not the shorter ones, so you have to make adjustments. The difference would be relatively slight on the 180 (I'd guess 1/2 stop or less) but worth considering on the 125mm where it would be more like 1 1/3 stop. Somebody who is better on the math will give you something better than those guesses.

[Gordon Flodders]

Hi Robert, I have a view camera fitted with a Copal 0 shutter. I have screwed many different focal length lens elements into it and had spectacular results. I now swap elements in this manner without changing the shutter of which I know the speeds to be reliable.
Checking sharpness via the ground glass is very good advice and after a while you will learn to notice right away if a lens is not up to scratch (excuse the pun). I have also found that different spacing using shims tends to affect the image sharpness at the edges only, nothing more. What you are doing is sensible and cost effective. Some of my highest resolution lenses have damaged elements in some way or another, some have chips, separation or have hit the concrete sometime in their life!
Strangest thing is sometimes, the more defective the lens elements are, the better the results, large format is like that :p


GF.

[Cor]

Hi Gordon,

I have swapped a few lenses from older Compur lenses with the old shutter speed set to more modern (Polaroid) Copal shutters. I measured faithfully the total length in the old and new shutter, and they always matched.

But how about the different F-stop scales, Gordon..you have a few different ones for each lens?

Best,

Cor


Hi Robert, I have a view camera fitted with a Copal 0 shutter. I have screwed many different focal length lens elements into it and had spectacular results. I now swap elements in this manner without changing the shutter of which I know the speeds to be reliable.
Checking sharpness via the ground glass is very good advice and after a while you will learn to notice right away if a lens is not up to scratch (excuse the pun). I have also found that different spacing using shims tends to affect the image sharpness at the edges only, nothing more. What you are doing is sensible and cost effective. Some of my highest resolution lenses have damaged elements in some way or another, some have chips, separation or have hit the concrete sometime in their life!
Strangest thing is sometimes, the more defective the lens elements are, the better the results, large format is like that :p


GF.

[Robert Vigurs]

I thank you all for your responses. I suspected the shutters would be manufactured to a fixed spec. Robert

[Gordon Flodders]

I have 90mm f5.6 Super Angulon and Symmar S 150mm elements, both of which are f5.6. The Copal 0 shutter's max aperture is also f5.6, so there's no problem. I found that if I screw elements of either f4.7 or f8 max aperture into the same shutter and use B/W film I experience no signs of under or over exposure, probably due to the film having such a wide exposure latitude, but I'd not try this with colour reversal film as it will only tolerate a very narrow exposure latitude of around half a stop.
This cheaper method of interchanging lenses saves having several shutters with possibly differentiating speeds confusing the mix and the idea certainly works for me.

GF.

[Cor]

Thanks for the reply Gordon,

I agree that 4.7 is not that different from 5.6 (about half a stop faster) but f8 is 1 stop slower, so I am surprised you do not see much difference on your negative.

I made F-stop scales myself (anybody knowing a a handier method: please chime in).

I took a lens with it's factory f-stop scale.

Focused on infinity (ie a building far away)

Than pointed the camera at an evenly and consistent lit wall (check with a spot meter!).

Pointed said spot meter to the middle of the groundglas (used a second tripod for that)

Take care to shield the spotmeter from stray light (I put my darkcloth over it)

Read the EV value on all different F-stops (usually nicely fits)

Mounted the other lens with out the F-stop scale in the same way as above.

Closed down the aperture and marked the positions on the scale based on previous EV measurements.

Best,

Cor

[Robert Vigurs]

I received the 180mm W and 125mm W elements from Japan today. All four are in really beautiful shape. I paid $83. The same seller had a Fujinon 150w, late model, in a Copal 0. I bought this for $110, as he specified the shutter was excellent. I can use this for the 125mm, as well as the 150. I like the idea of changing out elements in mounted shutter. Will have to find a way of keeping them clean and secure until use. The 180mm, however, screws perfectly in to an old Compur I have. I loaded up 8 film holders today with Ilford Delta 100, as I am leaving for the Mojave desert Wednesday. Death Valley. I know the area well. I also am taking my Hasselblad, and an old Mamiya 645j. I get great effects with fast moving freight trains with the focal plane shutter on the Mamiya. I will take extra 4x5 film and a changing bag just in case I need more 4x5. Boy, that's my idea of heaven. Three cameras, lots of film, lots of time driving the VW camper through the desert!