f6.8 Copal shutter?

[blevblev]

I'm on the list of those waiting the delivery of a Wanderlust Travelwide camera. There is a note on their site that says "Designed for the Schneider Angulon 90mm ƒ/6.8" but you can use other 90s. I like the small size of the Schneider so I went ahead and found an Angulon 90 on ebay in a Compur #0 shutter. I don't like the fact that the shutter speeds are marked as 1, 2, 5, 10, 25, 50...etc instead of the usual 1, 2, 4, 8, 15, 30...etc. I found a f5.6 Copal #0 shutter. My question is, does it make a difference that the shutter starts on 5.6 instead of 6.8? Can I simply not open it up further than the 1/3 stop after the 5.6. I've seen f6.8 shutters that only have two 1/3 stops between 6.8 and 8, which leads me to believe that the first 1/3 stop mark after the 5.6 mark is the same as 6.8. Are there size differences I'm not taking into consideration?

Bob

[DrTang]

are you ever going to shoot wide open anyway? esp hand held??


I doubt you'd open it up beyond 8 or 11...ever

[Toyon]

Compur shutters are great. The difference between the old style speed settings, and modern ones are trivial. Save yourself some money and adjust to the Compur. It is a lot better, IMHO, than the Angulon.

[blevblev]

Probably not, but my question is is the difference between a 5.6 shutter and a 6.8 shutter simply the markings on the shutter or is there some difference in the size of the aperture - which would affect all f-stop settings.

[Bob Salomon]

Shutters are not marked in F stops, they are marked in shutter speeds. The aperture scales are held on to the shutter by two small screws. So aperture scales are easily changed. However, you have an ancient lens so it is very unlikely that Schneider still has scale sets for a 90mm Angulon. But any good camera repair person can make new scales for you as blank scales are available.
Your 0 shutter does not know if a 23mm 5.6 Rodenstock lens or a 150mm Apo Symmar is mounted in it. The only difference is the set of aperture scales mounted on the shutter.
Since you are in Huntinton go ask Jimmy Koh on Jerusalem Ave in Bellmore.

[Dan Fromm]

Probably not, but my question is is the difference between a 5.6 shutter and a 6.8 shutter simply the markings on the shutter or is there some difference in the size of the aperture - which would affect all f-stop settings.

The Compur/Copal/Prontor/Seiko #0 standard shutter opens to 24 mm. As Bob has already said, the aperture scales are lens specific. Get the right scale for your lens or learn where "wide open" for a 90/6.8 Angulon is on the scale you have and adjust accordingly. To do this, open the shutter (set it to "T" and fire it or use the press focus/blade arrestor), open the aperture as wide as it will go, hold it at arms length with the front facing you and stop down until you can just see the blades. Open up until the blades just vanish. Iterate a couple of times. The aperture indicator will then point to "f/6.8" for your lens. I expect it will point more-or-less to f/8, half a stop smaller than the true aperture. And then, to set the aperture to f/"x", pick the marked aperture that is "x + 1/2 stop" and open up half a stop.

As has been said already, learn to use y'r Compur's shutter speeds.

If you must use your Copal you'll be OK. I have a #0 Seikosha whose maximum aperture is limited, i.e., that doesn't open to 24 mm, but it is a relatively rare exception to the #0 standard.

[blevblev]

Thanks

[DrTang]

Probably not, but my question is is the difference between a 5.6 shutter and a 6.8 shutter simply the markings on the shutter or is there some difference in the size of the aperture - which would affect all f-stop settings.

I see.. yes.. I'm not sure either.. I have a lot of lenses front mounted onto shuttesr and other lenses stuck into odd shutters and all kinds of arraingements

and I also wonder if it is just a matter of the widest opening 'working or not (ie: the lens is 6.8 no matter if you open up to a marked 4.5 or whatever but the rest of the marked settings past the lenses speed are okay) or is the whole physics of the thing tweeked so that every marked aperture is off??

I shoot B&W so half a stop this way or that is no biggie..but in color it could matter

[blevblev]

Right. I'm thinking that if I just don't open the aperture wider than 6.8 it will be fine.

[Kirk Gittings]

Right. I'm thinking that if I just don't open the aperture wider than 6.8 it will be fine.

You can open it up wider but just remember that it is still only 6.8.

[Michael E]

What lens used to be mounted in that shutter? If it was also a 90mm lens, you are good to go. Your Angulon 6.8 still won't become a 5.6, because the lens cells limit the maximum aperture. If another focal length was mounted in this shutter, the f-stop scale is useless - every single marking, not only the maximum aperture.