Replacing Industar-50 Elements

[lost eden]

I have 2x rigid Industar-50 lenses. The first is a 1959 ZM39 'pancake' that I bought thinking that as it's an M39 mount it would work on my FED-2 & Zorki 4; I soon discovered that this was not the case! The second is a 1968 specimen of the longer rigid version & came on my Zorki 4.

I don't own a Zenit so I can't use the ZM39. The front element of the other one that I can use however has a lot of cleaning scratches on it. I'm wondering how difficult it would be to dismantle both lenses & transfer the clean glass elements from the ZM39 to the other?

I've searched online & found guides for dismantling the lenses as far as the threads for cleaning/relubing, but none that go as far as dismantling the optics.

How difficult a job would this be? I imagine that I wouldn't just be able to do a straight transfer & that I'll have to focus/align/calibrate the elements?

 

[mooge]

dunno about calibration, but getting the front group out is simple (if you have the tools). around the lens there are two slotted rings, turn the outer one to remove the front group. that's it...

 

[Valkir1987]

Its easily done. The rangefinder rigid version is in fact a Zenit one screwed on an extension tube. The rangefinder cam tube is sometimes glued to the lens, and it needs some spirit, oil and a night of patience to be unscrewed safely.
You don't have to exchange lens elements.

Good luck!

 

[Gabriel M.A.]

I suggest this thread get moved to the Mad Gearhead Scientist forum so it gets the proper attention/exposure.

 

[mtargz]

Unscrewing the front and rear groups doesn't even require tools - with two nails, I can apply enough force to remove the rings holding them in place.

I use it occasionally to swap between the ultra-clean and mechanically-smooth late black version, and the old beat-up scratched one my grandfather used to have: The front block had fungus (now cleaned, but damage left) and scratches all over, and gives quite a soft effect when used wide-open.

 

[Veloman]

another possibility

another possibility

Is your Industar for RF one with detachable cylinder/rangefinder coupling, and the one meant for SLR with inner threading? In that case, why don't you just swap the respective parts? (I'll try to take some pics to clear up...)

Oops, Valkir1987 already mentioned it... Sorry!

 

[lost eden]

I feel a little silly for not noticing that the RF one is just a Zenit one on an extension tube! Sure enough, 1 screw & a fit of brute force & it came apart. I discovered when dismantling my Industar 26M for relubing that an uninflated balloon in each hand gives you that little bit extra grip you need (like using a rubber band on a stubborn jar lid)!

In the end I decided that whilst I had the screwdrivers out I would investigate dismantling further & ended up separating & cleaning all of the individual elements - I have no idea how dust & dirt managed to get *between* the two front elements...

I cleaned off all the old grease & will apply some new lithium grease to it tomorrow. For now the rings & the extension tube are soaking in a glass of Coca Cola to clean them up nicely 😉

Thanks for your help guys, the knowledge on this forum never ceases to amaze me!