Computar F9 Lenses Documents and Questions on Shutter

[kzhou22]

Good evening from 11.7.2025.
I happened to encounter the possible merchant documents of Computar f9 lenses recently, they are attached below.
They brought up several questions for me.

In the documents, 240mm, 270m and 305mm lenses claims to all come with a copal 3 shutter, if requested. But most people who owns any of these three lenses have the elements mounted in a newer copal 3s shutter, such as Mr. Sandy King.

I encountered several Computar lenses recently both online and in person, which I will also have images attached below:
A Computar 305mm f9 in a rather old copal 3 shutter which works properly;
A 240mm f9 in a copal 3s shutter with customized aperture scale, also works properly;
And a 240mm f9 in an older copal 3 shutter, but with an uncustomized scale, not sure if it works properly until it arrives next Monday.
I wonder if this specific version of the copal 3 shutter have interchangeable threads with the later 3s shutters?

 

[kzhou22]

Images of the known lenses attached. As you can see, the second 240mm f9 comes with a copal 3 shutter with a scale from 4.5 to 64, while the other two lenses works properly in their copal 3 and 3s.

The 305mm and one of the 240mm seems to have the same generation of early copal 3 shutter. According to previous posts around Computars, 240mm elements can screw directly into a 3s shutter, like in the second image.

Are there any other evidence that can prove the earlier copal 3 and newer 3s have the same threads and iris dias?

 

[Dan Fromm]

Are there any other evidence that can prove the earlier copal 3 and newer 3s have the same threads and iris dias?

The two are different. See "Copal shutters" in https://skgrimes.com/shutters/

 

[kzhou22]

The two are different. See "Copal shutters" in https://skgrimes.com/shutters/

It seems like the older copal 3 shutters are actually 3s standard according to this seller on eBay. Interesting.

 

[kzhou22]

It make sense if the older copal 3 shutters are actually 3s standard and was renamed to distinguish the difference in size from modern 3 shutters. This explains why the same computars can dwell in either an old copal 3 or a newer 3s with no issues. I wonder if an Angulon 210mm f6.8 is under the same roof, while the retaining ring for it is unfortunately different from either a modern 3s or 3.

 

[xkaes]

This "issue" appears with Fujinon lenses -- and perhaps others as well. Fuji literature seems to list lenses with #3 shutters, even when "some" lenses were supplied with to #3s shutters. Talk about confusing.

As to adapters for one shutter to another -- that would add distance and, I would think, "throw the lens spacing off".

 

[kzhou22]

This "issue" appears with Fujinon lenses -- and perhaps others as well. Fuji literature seems to list lenses with #3 shutters, even when "some" lenses were supplied with to #3s shutters. Talk about confusing.

As to adapters for one shutter to another -- that would add distance and, I would think, "throw the lens spacing off".

That is some interesting information. It is also weird that the images on the merchant document for computars does show the shape of an old copal 3 instead of a smaller 3s, probably because 3s still didn’t exist back then…… I wonder if any user of the computer lenses have spacing issues.

 

[Dan Fromm]

Hmm. According to data on SKGrimes' site (link in post #3 about), #3 Copal shutters' tubes are threaded M58x0.75 front and rear and the tube length is 32 mm. #3S, M56x0.75 and 28.6 mm.

Cells that fit one won't fit the other. Adapters for mounting cells that fit a #3 in a #3S are possible. Putting cells that natively fit a #3S in a #3 is impossible.

Fellows, stop speculating and pay attention to the data.

 

[kzhou22]

Hmm. According to data on SKGrimes' site (link in post #3 about), #3 Copal shutters' tubes are threaded M58x0.75 front and rear and the tube length is 32 mm. #3S, M56x0.75 and 28.6 mm.

Cells that fit one won't fit the other. Adapters for mounting cells that fit a #3 in a #3S are possible. Putting cells that natively fit a #3S in a #3 is impossible.

Fellows, stop speculating and pay attention to the data.

Maybe I will measure some of them precisely when I have them handy soon. Although more than one site stated that the older copal 3 might have a difference in specs, I might as well prove it to myself than guessing.

 

[kzhou22]

It is sad to confirm that at least the copal 3 model on 210mm f6.8 angulon is nothing close to a standard copal 3 mount. Computar is still on its way……

 

[xkaes]

To confuse things even more some (many? / most?) Copal #3s shutters are marked Copal No. 3 -- without the "s". A while ago, I got a great deal on a Copal No. 3 shutter because it had some problems. I was able to fix & repair the problems and then discovered that it was a 3s shutter. That didn't make any difference for my purposes, and the seller assumed it was a Copal No. 3 shutter because that was how it was marked.

Here's how one EBAY seller describes it. He is selling a #3s shutter that is marked #3.

3S is an old standard and existing 3S shutters are rare.
Please check the compatible lenses yourself.
This item is stamped with "No.3".
However, that is because the screw standard
for No.3 was changed a long time ago.
Shutters before the new No.3 standard were sold as No.3, and later,
to distinguish between the new No.3 and the old No.3,
the old No.3 was renamed No.3S.

Buyer beware!

 

[kzhou22]

To confuse things even more some (many? / most?) Copal #3s shutters are marked Copal No. 3 -- without the "s". A while ago, I got a great deal on a Copal No. 3 shutter because it had some problems. I was able to fix & repair the problems and then discovered that it was a 3s shutter. That didn't make any difference for my purposes, and the seller assumed it was a Copal No. 3 shutter because that was how it was marked.
Buyer beware!

Thank you for the clarification! I’m afraid that this is the case for Computars! I just measured the specs of the old copal 3 on the Computar and it resembles the standard of a copal 3s. The lens is very sharp and works properly. It also shares the retaining ring with a modern 3s. This makes 210mm Angulon an outlier because it has a “copal 3” shutter 1mm smaller than the Computar’s.

 

[DREW WILEY]

The confusion arises from some listings simply abbreviating any of these to "Copal 3". And the designation of "S" doesn't necessarily appear on the lenses themselves. Contrary to some previous posts, The "3S" is EARLIER than the last round of "modern"Copal 3. The "S" shutters are evident by an extra lever. Note the picture in post #4. The 3S shutters also had multi-bladed apertures, unlike later ones. But there were two different versions of 3S itself, with slightly different diameters.

Several of the Computar f/9 focal lengths were designed to be interchangeable in the same shutter.

 

[David Lindquist]

It is sad to confirm that at least the copal 3 model on 210mm f6.8 angulon is nothing close to a standard copal 3 mount. Computar is still on its way……

Back in the day Copal supplied Schneider with No. 3 Copal shutters modified to accept lenses made to fit the No. 3 Compound shutter. Lenses included the 210 mm Angulon, the 210 mm Xenar, the 300 mm (convertible) Symmar and the 360 mm Tele-Xenar. Nominal thread O.D. for these lenses made to fit the No. 3 Compound was 55.69 mm.

Also see (once LFPF is running): https://www.largeformatphotography.info/forum/showthread.php?155781-Copal-3-Shutter

David

 

[kzhou22]

Back in the day Copal supplied Schneider with No. 3 Copal shutters modified to accept lenses made to fit the No. 3 Compound shutter. Lenses included the 210 mm Angulon, the 210 mm Xenar, the 300 mm (convertible) Symmar and the 360 mm Tele-Xenar. Nominal thread O.D. for these lenses made to fit the No. 3 Compound was 55.69 mm.

Also see (once LFPF is running): https://www.largeformatphotography.info/forum/showthread.php?155781-Copal-3-Shutter

David

Thank you for providing such helpful information! I did encounter an angulon in a compound shutter once before, beautiful. Funny that it only goes to f32.