Aperture settings on Ansco 1A Advanced folder?

jay moussy · Mar 1, 2021

A friend of the family gave me this camera. time to put some film in it!

The aperture dial reads 7.5, 8, 11, 16, 22, 32, 45.
Are these our modern-day f numbers?
(for reference shutter speed range is 1/100 to one sec, plus T, B)

Bonus question: the film backing provision are thin, 1/4 inch wide blades, upper and lower. like so:

____________________ Film
_ _ "blades"
____________________ Body back

I will need to supplement that for the 120 film size.
should I just add wider strips on the "blades"
I think there should be added support on emulsion side, as the gate is 65 mm wide.

ic-racer · Mar 1, 2021

Can you post a picture of the film back, I'm not following.

Rick A · Mar 1, 2021

jay moussy said:
A friend of the family gave me this camera. time to put some film in it!

The aperture dial reads 7.5, 8, 11, 16, 22, 32, 45.
Are these our modern-day f numbers?
(for reference shutter speed range is 1/100 to one sec, plus T, B)

Bonus question: the film backing provision are thin, 1/4 inch wide blades, upper and lower. like so:

____________________ Film
_ _ "blades"
____________________ Body back

I will need to supplement that for the 120 film size.
should I just add wider strips on the "blades"
I think there should be added support on emulsion side, as the gate is 65 mm wide.

Those appear to be modern F numbers. I can't answer the other question, I think pictures would help.
An article that might help with f numbers: http://throughavintagelens.com/2010...CmDeIwdvdbJP9humPsIORhkhPaFANgiAv6AV06PonQCD8

removed account4 · Mar 1, 2021

hi jay

not sure of the questions about the. blades &c, sometimes it just takes some tinkering
here's a chart about f#'s
like RickA said the number you listed are both half and whole stops.
have fun with the new toy !
John

jay moussy · Mar 1, 2021

Thanks for the document @Rick A, useful as I have another Ansco featuring the "U.S. System" and hadn't found the right, complete reference before.

@jnantz , I have same chart, and was wondering if my camera markings were on there and which ones!

Detail view of body back with "blades", designed for 116 film:

... and shown with a 120 backing paper, floating between the 'blades", illustrating the need for addition of support:

I will also have to add strips to the film gate, I believe.

(minor edits)

Nicholas Lindan · Mar 2, 2021

You might try attaching a flat piece of metal or strong thin plastic to the 'blades' and make a pressure plate for the back.

I'm not sure about the gate. In a modern gate there are two sets of rails, an inner set for the film to run on and an outer set for the backing paper. The outer set is raised up by the film thickness. If you can adjust the lens focusing stop forward then you could lay the new gate on the old one.

jay moussy · Mar 2, 2021

Nicholas Lindan said:
You might try attaching a flat piece of metal or strong thin plastic to the 'blades' and make a pressure plate for the back.

I'm not sure about the gate. In a modern gate there are two sets of rails, an inner set for the film to run on and an outer set for the backing paper. The outer set is raised up by the film thickness. If you can adjust the lens focusing stop forward then you could lay the new gate on the old one.

Yes, a thin plastic sheet of plastic, and maybe a bit of foam behind it for pressure.
I can make a trial piece attached with painter's blue tape and do a dry run with just backing paper first . My supply spool will be 120 plus wall anchors method, so it is a bit funky as well.

The gate strip idea is about this:

The 120 film width will probably fall in the open space?

jay moussy · Aug 3, 2021

Revisiting my old post to add a picture of the aperture dial on the Ansco 1A folder (circa 1925, sim. the Speedex, I read).

so, the dial reads 7.5 8 11 16 22 32 45

@Rick A kindly answered in post #3 and thought these were "modern f-numbers, but re-reading the document he linked I am not sure. If these are of the "U.S. System", per the chart in post #4, the corresponding modern f numbers would be approximately f 3.5 to f 28.
Would that make sense on a folder of that era?

To really settle could I do some measured test, or eyeball the actual aperture diameter and use it compute something?

BTW, I have been reading this guy up for film, so I want to go for it!

shutterfinger · Aug 3, 2021

Those are US numbers although some are not in the linked/posted tables
Aperture number=lens focal length/diameter of the entrance pupil. The Entrance pupil is the aperture opening as viewed through the front lens element. A good fine graduation ruler will surface across the center of the lens.
1 inch=25.4 millimeters.

jay moussy · Aug 3, 2021

I see.
aperture set to native 7.5 measures 12 mm (+/-)
aperture native 45 measures 3 mm (+/-)
It seems to me that the lens focal length must be around 120 mm, maybe a little less.

With these approximate numbers, we would get 7.5 corresponding to f10 to and 45 to f36

Now, the original manual, shared with the Speedex model, speaks of "F11" and recommends: "In bright sunshine, use 1/25 and F16", and also advises to read the accompanying booklet "Expert Camera Operation made Easy" Some humor!

shutterfinger · Aug 3, 2021

Is this your camera? http://piercevaubel.com/cam/catalogs/1915anscolp388.htm pages 16 & 17. If so the lens is 4 7/8 inch / 123.8 mm.

jay moussy · Aug 4, 2021

Maybe not, mine came a design cycle later, in1924-25.

I am familiar with the document you posted, as I read it to find information on my 1915 Buster Brown Folding, page 39, and its Actus shutter, page 7. Actus shutter works but inner springs get tired by the 7th actuation, shutter blades do not fully retract, even at the topmost 1/50.

I appreciate your expert interest in this!

Update: I found the "Expert...Made Easy" booklet the 2A Advanced manual refers to:
https://www.cameramanuals.org/booklets/expert_camera_operation_made_easy-agfa.pdf

On page 10, it says the U.S. System was used for single Achromatic and Rapid Rectilinear lenses, and the F system for better Anastigmat ones.

Also: there is no such thing as "7.5" in the U.S. System, it seems, so, as I have a "7.5" marking, this is an F scale?

Another interesting tidbit from the "Expert..." document, page 14:
U. S. 4 (F 8) is the limit of speed for Recti-linear lens. If a still faster lens is desired, it is necessary to pass over into the Anastigmat class, as more optical corrections are necessary
to permit stops larger than F 8. For the same reason, it is not practical to provide extra
speed in Anastigmat lenses in equally big jumps-such as from U. S. 4 to U. S. 2, and
from U. S. 2 to U. S. 1. In practice, the lens is made as much faster than F 8 as is possible without sacrificing other Anastigmat qualities or increasing the cost unduly.
(there is more on the subject)

Cool stuff!

Donald Qualls · Aug 4, 2021

A measured aperture of 3 mm on a 120+ mm lens certainly looks like f/45 to me (actual aperture for f/45 at 124 mm would be about 2.76 mm).

jay moussy · Aug 4, 2021

Donald Qualls said:
A measured aperture of 3 mm on a 120+ mm lens certainly looks like f/45 to me (actual aperture for f/45 at 124 mm would be about 2.76 mm).

Is it consistent with the nature of lenses, and what was made during that era?
I know some folks have Speedexes on here, the sister model, but could be later issues, again, with better lenses, leading to different working aperture ranges?

Donald Qualls · Aug 4, 2021

Lenses of that size are likely to be f/8-ish maximum aperture, and f/45 isn't at all uncommon for 120+ mm lenses, especially those from a century ago. Generally, the bigger the film and longer the lens, the smaller the relative aperture can be before sharpness declines noticeably due to diffraction -- and in the days of contact printing (surely including the manufacturer of that 1A) the standards for that were less stringent than they are in the modern age of enlargement and high resolution scanning. I wouldn't be surprised to f/64 on a lens similar to this from that era; the only reason you wouldn't is because film was slow back then, and f/64 would be a time exposure even in full daylight on ASA 12...

Ian C · Aug 4, 2021

Regarding the photo of the lens & shutter shown in post #8:

I don’t see anything unusual about the aperture scale. The sequence conforms to the modern (U.S.) standard. The wide-open value of the lens is f/7.5. It lets in about 1/5 of a stop more than f/8, a trivial difference.

nosmok · Aug 5, 2021

What Ian C said. I'll add only that "U.S. System" was the "'Universal Stop' System", and had nothing to do with the "United States".

Aperture settings on Ansco 1A Advanced folder?

Advertiser

Privacy & Transparency

Privacy & Transparency