I recently got a very old agfa silette camera, and there is this dial with the "R" that is used to rewind the film. In addition to that, is has a little window showing something below - What is that for?

I am not even sure how this thing rotates. When I rotate the rewind dial, the inside only rotates very slowly and mostly at random. I was able to get it to some different positions but it takes me like 3-4 full turns depending on the force I use to advance to the next position of that plate. It has some degree numbers on it but also just some letters.

What is that for and how is that being used, given that it only turns at what seems to be random?

beautiful collage

  • 4
    \$\begingroup\$ The exposure counter? I have taken "CT" exposures? I don't think so.. The values on the dial are "C", "CT", "CN27", "13º", "25º", "K" and some more which are hard to hit. Also note that if I take a picture, rewind the film, cock the shutter or anything, the dial does not turn or advance. \$\endgroup\$
    – confetti
    Oct 1, 2019 at 21:48
  • \$\begingroup\$ Does the outer part lift up and turn to move the window deliberately? \$\endgroup\$ Oct 2, 2019 at 11:10
  • \$\begingroup\$ @AndrewMorton the outer part does lift up but the window doesnt get affected by that action. Edit: After reading the answers, I assume that's how it should work/rotate though, maybe it's just slightly broken on my model then? \$\endgroup\$
    – confetti
    Oct 3, 2019 at 13:34
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    \$\begingroup\$ FYI, the Agfa Silette is not an SLR. SLR stands for "single lens reflex" and indicates that a mirror is used to provide a through-the-lens view in the viewfinder. The Agfa Silette was a series of simple viewfinder cameras, no mirrors involved. There were also the Super Silette models which were rangefinders. \$\endgroup\$
    – G_H
    Oct 3, 2019 at 15:17
  • 1
    \$\begingroup\$ @G_H Thank you for that information, I have edited the title and tags. \$\endgroup\$
    – confetti
    Oct 3, 2019 at 21:44

4 Answers 4


This is just a passive dial (that does not communicating anything to the camera mechanism), meant as a memorizing aid for the film type and speed inserted.

The degree values are DIN speed numbers.

C seems to be a shorthand for generic "Color" film.

CT, CN17 and K appear to be shorthands for various Agfa film stocks that were contemporary for that camera:

"CT" ("Color Transparency") is found in the name of various color slide films, eg "Chrome CT 18", though the latter was apparently only introduced 1958, so the intent could have been generic "Color Transparency"

"Agfacolor CN17" was a 17 DIN/40 ISO "Color Negative" film. There was VERY likely no "CN27" when that camera was made - 400 ISO color negative films weren't marketed in the late 1950s AFAIK.

"Agfacolor K" was a tungsten-balanced color negative film. "K" could have been for "Kunstlicht" (artifical lighting) or "Kelvin", as a tungsten film is designed for a different color temperature in Kelvins.

It would appear that different Silette models, and probably also their export versions, had varied values on this dial (eg old english language manuals seem to suggest some models had ISO values).

  • 4
    \$\begingroup\$ See page 6 of photo-manuals.com/manual/agfa/medium-format-camera/… for an explanation and assets.community.lomography.com/25/… for a photo. The letters don't match the English language description, so you camera was sold in a non-English market. \$\endgroup\$
    – K7AAY
    Oct 2, 2019 at 22:21
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    \$\begingroup\$ As we know, Agfa was a german maker that sold mostly in western europe - I am amazed an english language manual actually exists. \$\endgroup\$ Oct 2, 2019 at 22:54
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    \$\begingroup\$ When I worked in a camera chain we saw many Anglophone Agfas in South Florida. \$\endgroup\$
    – K7AAY
    Oct 2, 2019 at 22:59

This camera was mainly intended for use by amateur photographers who only occasionally used the camera. Film was loaded, some pictures taken, the camera was generally set-aside to be picked up latter for an occasion. This second or perhaps third session might be next week or next month or even next year. When the roll was finished, then it was sent out to the photofinisher for developing and printing.

What I what you to understand, it was common for the loaded camera to sit in a drawer for some time. Naturally, one tended to forget what type of film was loaded. The letters and numbers on the wheel you have discovered is a reminder. The letters stand for film types. The lettering, in in English was CT for color transparency (slide film) -- CN for color negative film, B or BK for black & white.

In that era, film speed testing was carried out by the various standards bureaus of counties. In North America it was ASA (American Standards Association). In Germany it was DIN (Deutsche Industrial Norm), BSI (British Standards Institute), in Russia GOST etc. Each used different methods, it was confusing, all were consolidated under the authority of the International Organization for Standardization of Geneva and now called ISO.

The DIN system of Europe was Logarithmic. 100 ISO = 21⁰ -- 200 ISO = 24⁰ -- 400 ISO = 27⁰ (approximate conversion.

However, the wheel was a reminder device, it is not connected to the camera’s mechanism, it serves only to remind the photographer what film was inside.

  • \$\begingroup\$ AFAIK ISO is noted as a combination of ASA and DIN, so 400 ASA is DIN 27⁰ and ISO 400/27⁰ \$\endgroup\$
    – timvrhn
    Oct 2, 2019 at 8:38
  • \$\begingroup\$ On older cameras, as a kid, I'd put the part of the carton the film came in, in the bottom of the camera case. That worked quite well! \$\endgroup\$
    – Tim
    Oct 2, 2019 at 11:38
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    \$\begingroup\$ My Pentax ME super had a holder on the back. You cut off part of the box and pushed it into the holder. \$\endgroup\$
    – Bonzo
    Oct 2, 2019 at 11:54
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    \$\begingroup\$ Interestingly, these "film clip holders" seem to be a later invention than such marker dials! \$\endgroup\$ Oct 2, 2019 at 20:24

The dial came before the film box holder because when this camera was made it wasn't uncommon to reload 35mm film canisters from bulk 500ft rolls of film, so there wouldn't necessarily have been a box each time the camera was loaded.


I don't know about the "CT" (my guess is that it reads the barcode from the film cartridge and automatically sets film sensitivity) but the other numbers are clearly DIN settings corresponding to ASA (and nowadays ISO).

ASA100 corresponds to DIN21°, and basically you go up 1°DIN for 1/3EV, so ASA200 corresponds to DIN24° and ASA400 to DIN27°.

  • 5
    \$\begingroup\$ Agfa Silettes predate DX coding by decades.... and the some models (this one looks like one of these) have no exposure meter, let alone exposure automation, so the camera does not care about the film speed. \$\endgroup\$ Oct 1, 2019 at 22:14
  • \$\begingroup\$ CT = Color Transparency film (Kodachrome -- Ektachrome -- Agfachrome etc. \$\endgroup\$ Oct 2, 2019 at 13:37

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