Fed/Ind collapsable 3.5/50 differences

[fidget]

Hi, I've recently received a camera with a collapsable I-50 fitted and I already have a (not tried yet) I-50 collapsable. I noticed that the FED 3.5/50 is clearly a different lens. It's about 6mm shorter than the Industars and has a different infinity lock. I have used the FED, which was really quite good (after I had cleaned some gooky residue spots off the inside of the rear element), so I'm sure that it is at it's correct length.
What is the difference between these lenses?

 

[fidget]

I just thought that I could have a quick check of the relative focal lengths by mounting these lenses on my m39 SLR. When set to infinity, the lenses focus at about 200mm, macro work! I was surprised to see that the shorter lens (FED) had a slightly narrower field of view than the Industars. Not at all what I expected, considering that it is at least 6mm shorter.
If it ever stops raining I will spoil some film with these lenses.

 

[Ash]

I've wondered the same, I have a fed 50mm and a I-50 collapsible, and I can see they arent identical. Never really noted the difference between them though.

 

[Jocko]

The Fed collapsible lens is an Industar 10, and I believe that the industar 22 (found on the earlier Zorkis) is simply the same lens, optically at least, but assembled by KMZ. Apparently the earliest examples were actually made from FED parts.

The Industar 50, which replaced the I-22 c.1953 would seem to be an improved design, with somewhat better performance - our friend nate has an interesting chart! -
http://www.commiecameras.com/sov/35mmrangefindercameras/lenses/index.htm

Cheers, Ian

 

[fidget]

Thanks Ian, looks interesting. Wonder how my FED has become so much shorter than the I-22.

 

[Ash]

to cut costs?

 

[Jocko]

Thanks Ian, looks interesting. Wonder how my FED has become so much shorter than the I-22.

Fidget - I'm wondering too 🙂 Princelle states that the I-22 was "a lens of the FED recovery" made "using original FED parts", but to be honest, I'm beginning to think that it must be a different design, although it's generally said to be indistinguishable in performance from the I-10...

Oh dear! 🙂

Cheers, Ian

 

[howpow]

Hi Fidget. I must admit I had never noticed the diffence in length until you raised the matter. Very Interesing. 😱

 

[fidget]

I must admit that I was hoping for a change in focal length between the FED & I-22/50, given that the FED is so much shorter. The chart that Ian linked is interesting, but doesn't give figure for the FED or I-10. Not that this matters, I'll run a film with examples of each.

 

[Jocko]

Fidget, as it's now apparent that the I-10 and I-22 are not the same lens, something else occurs to me...

It's hard to judge exactly, but, using some reference points about 15 feet away, I think the viewfinder of the FED 1 may show a fractionally smaller field of view than that of the Zorki 1. I thus wonder if the I-10 has the same focal length as FED's later standard lens, the I-61, variously given as 52.4, 53 and 55....

Anyway, It's a thought!

All the best. Ian