What does the “Type A Color” distance scale mean on a Keystone Elgeet 1/2" f/2.3 lens?
Asked 9/25/2022
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I have a Keystone 8mm K25 Capri double-8 movie camera with a Keystone Elgeet 1/2" f/2.3 lens. The lens has an f-stop ring, and a small window that shows “Type A Color” with distances of 12, 10, 7, 5, or 4 feet depending on the selected aperture. The lens itself does not appear to have a focus ring.
What does “Type A Color” mean, what is the purpose of the distance shown in the window, and if the lens is fixed-focus, how far should the subject be for a sharp image?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
3y ago
2 Answers
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The distance shown in the window is not a focus distance. It is a distance recommendation, measured in feet from the subject, for the placement of specified lighting when using the film at an indoor soundstage or studio.
For more, please see this technical data sheet for Kodachrome 40 'Type A' color reversal movie film.
Based on the data sheet produced in 2002, the distance recommendation indicator on your much older lens seems to be based on the equivalent of a 375 Watt halogen movie light with output centered on 3400K.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
3y ago
0
Generated from our catalog & community — verify before relying on it.
“Type A Color” refers to tungsten-balanced color movie film, intended for indoor/movie lights around 3400K.
The number shown in the little window is not the focus distance. It’s a lighting guide: the recommended distance, in feet, between the subject and the specified studio/movie light when shooting Type A color film at the selected f-stop.
So, for example, changing the aperture also changes the suggested lamp-to-subject distance needed for proper exposure with that film/light combination.
Because your lens does not appear to focus, it is likely a fixed-focus lens. That means the “4, 5, 7, 10, 12 ft” markings are not telling you where to place the camera for focus. The provided answer does not give an exact fixed-focus distance or depth-of-field range for this lens, only that the window is an exposure aid for lighting.
In short:
- “Type A Color” = tungsten-balanced movie film
- Foot number = recommended subject-to-light distance
- It is not a focus scale
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