Need help with a lens

Hi all!

I am very new in "business" but I would like to go more:) At this point I would like to build a very simple negative or paper camera (don't ask why:), I would very like to do it before buying a camera) So, I have a lens that I could use it but I could not found any information about it. It has this written on the front ring: Okolinar 1:4,5 F=21 cm Serie T Okoli - Gesellschaft, Stadtilm.

Do someone knows what this is, for what it supose to be and if I can use it for building the camera?
Thank you very much in advance!
A

What you have there is an enlarging lens from the 30s or earlier. Probably covers 13x18 cm, maybe larger. Building a camera is great fun, just go ahead and do it!

Thank you for the quick answer! Do you have more info about the lens? I would like do build a camera that focus by going closer or far away from the subject, how can I calculate the distance that I need between the lens and the negative? Thanks again!

I've seen one Okoli lens in really bad condition and only know that Okoli-Gesellschaft made enlargers prior to World War II. That's about it.

The distance should be about 21 cm, so if you make sure the lens slides back and forth to and farther from that distance, you'll be able to focus. It also depends on how close your subject is to the lens. For portraits, you'll probably want it farther than 21 cm, say 30-35 cm. But it all depends on the lens, test it by seeing the image it casts on any kind of ground glass - you can use cheap tracing paper, frosted plexi etc.

Thank you, now is clearer, I will start working and I will keep informed about the subject!