Wollensak shutter - US system for aperture?

[rrunnertexas]

I have a Seroco (Conley) 5X7 camera with a Wollensak shutter dated 1910.

The apertures are marked as . 8 16 32 64 . 256

Can anyone confirm that these are marked using the US system for apertures verses the later f/ system?

Also, is the first dot used to indicate 4 and the second dot a 128?

I attached an image of the shutter with this post to assist.

Thanks for the help.

[BrianShaw]

Yes they are. The dot under 256 is US/256; the one prior to that is US/128.

[Jac@stafford.net]

To avoid confusion for others, US refers to the Unified System created by the Royal Photographic Society in 1881.



US = F/stop

1 = 4
2 = 5.6
4 = 8
8 = 11
16 = 16
32 = 22
64 = 32
128 = 45
256 = 64

[rrunnertexas]

Thank you for the fast replies!

So, the first dot before the 8 might be for "4" which would be the equal to f/8?

[BrianShaw]

that would be a reasonable assumption.

[rrunnertexas]

Perfect.

I sure do appreciate the fast replies and help.

Now, off to make some images.

[BrianShaw]

I quite enjoy using old lenses like that. The run-of-the-mill Rapid Rectilinear I occasionally use is a surprisingly good performer. Enjoy!

[rrunnertexas]

Brian, I did make a few images with it and it does produce pretty nice images. The center was pretty sharp, however, outside the center sharpness fades away. Certainly has a different look to it.

I believe it was set at f/16, so as it is stopped down the image should be sharper throughout the frame?

The lens, shutter and entire camera really appeal to me. So old, yet work as they were made in about 1910.

[desertrat]

The dot just to the right of the 8 looks awful close to be a whole stop larger. I have a 5X7 symmetrical in a similar but older shutter that only opens a bit past the 8-US mark.

It is a rectilinear, but not rapid, as its actual largest opening is only about f11 (8-US).

I haven't shot film with it but from images examined with a loupe on the GG it should be a good performer.

[IanG]

Interesting, I have a similar shutter on an Aliance Roll-film Camera co 5x4 camera and made 1898-1904 with a modern scale. It depended on the camera manufacturer not the shutter manufacturer.

My shutter still sounds very smooth and appears to be accurate.

Ian

[Jim Noel]

I have and use th identical outfit as mentioned in the first posting.
The easiest way to remember the apertures is US (universal Standard) 16 = f 16. Then just count stops from there.
I don't know why your lens isn't relatively sharp, mine is and the shutter, with its limited speeds, is very accurate.

[rrunnertexas]

Jim,

I noticed in the images I took that the center was really nice, then the outside was "swirly" looking. Not sure how to describe it, exactly.

I sent out for developing a few more images, portraits, that I took with it this past weekend. Maybe in a week or so I will see what they look like and can post a shot.

The lens looks nice and clear, however, the shutter was not working well. The shutter has returned after a CLA and works great! Speeds are measured and most are as stated, a few off speed.