Lens and shutter, how to make them happy together:)

[highpeak]

Well, I got a 210 Symmar S F5.6 lens and a Copal #1 shutter for a really good price, put them together, fit very well. I am so happy about it. After play around for a while, I noticed that the aperture scale on the shutter only open to F6.3, so I lost about half stop. I searched a little bit on the forum, found out I need a new aperture scale for the lens ( the shutter was for the 210mm Komura F6.3 lens).

My question is-What is the max opening for Copal #1 shutter? If it's says like mine the max is 6.3, can it be modified to F5.6?

Another similar situation with my other lens, which is a commercial Congo in Copal Polaroid shutter. The lens max opening is F6.3, but the shutter is F8, again, is there anyway to modify the shutter to match the lens max opening?

Thanks for any help in advance.

Alex W.

 

[highpeak]

Sorry, the thread should be "Lens and shutter" not ns and shutter, don't know what happened. Is there any limit on the length of the title of the thread?

My mistake, can anyone help me correct the title?

Should be" Lens and shutter, how to make them happy together"

Thanks

 

[Ole]

My mistake, can anyone help me correct the title?

Should be" Lens and shutter, how to make them happy together"

Done.

 

[Roger Hicks]

Is the diaphragm fully open at the apertures mentioned? If so, no, you can't get any more speed. If it isn't, you can. A shutter doesn't have a fixed maximum relative aperture, because r.a. depends on the f.l. of the lens in it, but it does have a fixed maximum absolute aperture. Or am I misunderstanding your question?

 

[Steve Smith]

If the shutter used to have a 210mm lens in it and now has another lens of the same focal length in it, the aperture scale will be the same - assuming it was correct to start with.


Steve.

 

[Ole]

There are some shutters which have a pre-set "max opening", so that the apeture range for the intended lens uses the full range of the scale. Like the Syncro-Compur MXV type 1210-051.

Others have a maximum opening, and the aperture scale may start in the middle of the full range - like the Syncro-Compur MXV type 1210-000...

A shutter with an aperture scale made for one 210mm lens will not necessarily be correct for another 210mm lens, but with a very few exceptions should be close enough to be well within tolerances.

 

[GeorgesGiralt]

Hi Alex !
It appears I own the Komura 210 and a Symmar 210 (not S version, but...).
When I open the Copal iris full, one can see no blades protruding from the ring. So at 6.3 (which is BTW 1/3 stop apart from 5.6), the Copal is at it's maximal opening.
For F stop size, one must measure them as seen from the front of the lens, WITH the lens in place.
If you are lucky, the diameter of the F-stop with the Symmar-S when the Copal shows F:6.3 will be correct for 5.6. You will only need a different scale engraved from 5.6 instead of 6.3.
If not, you will need to adjust the Copal, and I do not know how to do this.
Hope this is clear enough for you to understand ;-)

 

[Nick Zentena]

My question is-What is the max opening for Copal #1 shutter? If it's says like mine the max is 6.3, can it be modified to F5.6?

Take out your ruler/calipers whatever and measure . The F/6.3 I'm guessing is what the scale currently fixed to the shutter is telling you. That just tells you what the last lens was.

 

[highpeak]

Thanks a lot, guys! Roger, the diaphragm is fully open, so, there is nothing I can do to gain more stops like you said. Too bad.

Georges, my Komura rear cell's cement is peeling off, I will try to re-cement it. If I am lucky, I can get it back to work. It seems like a fine lens and is
multi-coated!

Now, I measured the max opening with the Symmar front cell in place, it's about 35mm, so 210 divide by 35, I end up with 6, which is really close to 5.6. I will try to take some picture with it just the way it is to see what happened. For B&W, I don't think it's going to make much difference. I also will measure the rest of the stop to see if they are correct.

It's a very good experience for me to know a little bit more about the instrument I love.

Thanks for the helps again!

Alex W.

 

[GeorgesGiralt]

Well, the Komura is not so bad.
I use it when I go in the field because my Symmar with its Compur Electronic weight 700 gr !
I did not make measurements, but the Schneider seem to have more coverage.
And, of course, the Komura being of 70's vintage is multi coated, the Symmar is single coated. (I don't care, as i use 99 % B&W stock)
IMHO, the Copal is just fine for your Schneider lens as it is given for a size 1 shutter. I think the discrepancy you've got is a measuring error. It is really difficult to get this precisely.
As for the F stop calibration, Compur use a fixed F stop scale (as there is a 1/3 of a stop click) so they provide an adjustable lever between the F-stop lever and the actual diaphragm. This way, 5.6 is always written at the same place on the barrel the lens being a 210 or a 150 mm.
Copal use a different system. There is a direct connection between the F-stop lever and the diaphragm, one has to calibrate the F-stop markings to fit the lens. So you need as many F-stop scale as lenses you plan to put into a Copal shutter.

 

[epatsellis]

.
Copal use a different system. There is a direct connection between the F-stop lever and the diaphragm, one has to calibrate the F-stop markings to fit the lens. So you need as many F-stop scale as lenses you plan to put into a Copal shutter.

However, the Copal has the advantage of being linear, the distance from stop to stop is the same, a piece of tape and a few mins of time will garner you an aperture scale that is correct. Just move everything up 1/3 stop. (or one dot) Having said that, in reality, if you think 1/3 stop wider, e.g. 6.3 is really 5.6, it's quite usable as is.

Well, the Komura is not so bad.
I use it when I go in the field because my Symmar with its Compur Electronic weight 700 gr !

Yup, I have the same lens, and I recently bought a 210 angulon for the 8x10 in a compound, more movements on 8x10 and lighter to boot.


erie