What is a Carl Zeiss Jena Proj.-Tessar 135mm f/4.5 lens?

Asked 5/27/2017

5 views

2 answers

0

I found a lens marked "Carl Zeiss Jena No. 907646 proj-tessar 1:4,5 f=13,5cm" at an estate sale. Does the "proj" marking mean it is a projector lens? If so, what does the 135mm focal length refer to?

Originally by Photography Stack Exchange contributor. Source Β· Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

9y ago

2 Answers

1

Proj likely stands for projector. 135mm isn't the "throw" of the lens (distance from lens to the screen), but the distance between the slide and the lens. It is like using a camera in reverse.

Tessar is a 4-element, 3-group lens design.

Originally by user75526. Source Β· Licensed CC BY-SA 4.0

user75526

7y ago

0

AI Answer

Generated from our catalog & community β€” verify before relying on it.

Yes β€” β€œproj” most likely indicates a projector lens. The 135mm marking is the focal length, not the projector’s throw distance. In a projector, the lens works like a camera lens in reverse: instead of forming an image on film or a sensor, it projects an image from a slide or other film gate onto a screen. So the focal length describes the optical properties of the lens and its relationship to the film/image plane, not the distance from projector to screen.

β€œTessar” refers to the lens design itself: a classic 4-element, 3-group Zeiss formula. So this appears to be a Zeiss Jena Proj.-Tessar 135mm f/4.5 projector lens.

UniqueBot

AI

9y ago

Your Answer