What's the number on the Kaligar lenses?

[Cadger]

I've been collecting parts for a macrobinocular build for quite some time now. I just now started to wonder about the F-(?)number on the Kaligar lens from the Kalimar six sixty camera. My lens is marked with "No.F T83984". I have until now believed that the number was a part number, but looking at pictures of 1:2.8 f=80mm lenses online I find several different numbers. And I have also seen a couple of lenses with the same number also. So i don't think it's a serial number either.

So what is this number?

 

[bobasfett]

I’ve wondered t about this as well. Good thread

 

[scarf man]

The 80mm number is the focal length.

The f-number/f-stop is the ratio of the focal length to the diameter of the entrance pupil.

f-number - Wikipedia

en.wikipedia.org

 

[bobasfett]

The 80mm number is the focal length.

The f-number/f-stop is the ratio of the focal length to the diameter of the entrance pupil.

f-number - Wikipedia

en.wikipedia.org

I think he's asking about the FT83984 number

 

[scarf man]

I think he's asking about the FT83984 number

That is the f number. I called out the focal length (80mm), because it was pertinent to explaining the
f-number.

 

[bobasfett]

That is the f number. I called out the focal length (80mm), because it was pertinent to explaining the
f-number.

I guess I don’t understand how you are saying the F/stop number is FT83984. The numbers don’t seem to jive with the normal nomenclature. I’m not a photographer, just trying to understand your post.

 

[teecrooz]

I always thought it was the lens serial number. Most camera equipment is serialized.

 

[bobasfett]

I always thought it was the lens serial number. Most camera equipment is serialized.

That would make sense to me. I would have to dig all of mine out but I don’t believe any of the FT numbers are the same. On the one that’s handy, it’s FT83686 with the same lens info as the OP lens.

 

[scarf man]

I’m probably wrong about the f number. I just read up a bit more and it indeed doesn’t seem to fit the nomenclature. Sorry.

 

[Cadger]

That would make sense to me. I would have to dig all of mine out but I don’t believe any of the FT numbers are the same. On the one that’s handy, it’s FT83686 with the same lens info as the OP lens.

I said I've seen the same number. But the photo I saw with matching numbers seems to actually be (very well made and painted) resin casts. That will explaind the same number. So I think it's probably a serial number after all.