russian 35 nap projection lens

[leslie]

inspired by bolds thread on the b&h projector lenses i'm making a thread on the russian 35 nap series of lenses. these are big beasties indeed and quite heavy. my two cents worth of opinion is from my ebay searches these seem to be the cheapest anamorphic 2x stretch projector lens option at the moment the caveat being size, weight, make them unpopular choices i think  and that front element size would make for a expensive not to mention massive single focus solution probably. however my curiosity knows no bounds except when it come to mains line voltages lol.   so with out any further mucking around lets pull this beastie apart. the lens comes apart quite easily. the front cover i guess you would call has one small flat head screw in it then it just unscrews. i guess they didn't have locktite back then as none of the screws seem overly difficult to undo.

the ring with the measurements on it has three small flat head screw which hold it on. once there undone the ring falls off and you can either unscrew the focus ring backwards till it comes off or screw it forward and it will drag the front element with it. i did it backwards first then struggled to get the front element out put the focus ring back on and screwed it forwards till they both fell off the front. 

im kinda stuck at this point as i cant find my lens wrench and i think i need it too undo the back element. there is 6 small flat screws positioned around the back element on the housing however undoing them doesn't free the back element. i was hoping that the back element might fall out if i tipped it upside down but no it doesn't. if you saw my desk you'd understand how a lens wrench could go missing  ?   thats it for the first installment hopefully i will have more to share soon.

 

 

 

 

 

[leslie]

found the lens wrench  so more progress has been made

disassembled the back lens element this required the lens wrench and a lever inserted between the lens wrench legs for additional leverage as this was not inclined to let go. once i got it loose. there is two rings one on top of the other the first was a mission to loosen the second was easier then the lens just lifts out.

the front  lens housing has a  black metal surround that was a little tight to undo once that was off, had to take a moment to inspect it there was a thin metal cover, then underneath the lens seems to be stuck in with blutak gone hard. i mean it smells like blutak, looks like blutak so i'm calling it blutak. took a flat screwdriver to it , broke the seal all the way a round then just eased it out with my thumbs.

only thing remains is to remove the back lens from its holder. thats a job for tomorrow

one last pic of the lens disassembled

 

[Dr. Verbel']

https://www.eoshd.com/comments/topic/20638-35nap-2-3m-mod-–-precision-light-streaks-bokeh/

[leslie]

5 hours ago, Dr. Verbel' said:

https://www.eoshd.com/comments/topic/20638-35nap-2-3m-mod-–-precision-light-streaks-bokeh/

excellent thread, really impressive. i like the way you set up for testing with the individual legs for each lens, i think i will " borrow " that idea  ?

[leslie]

for posterity's sake here some measurements of the lenses and their housings the front lens comes in at 120 mm in its housing

without the housing its 99 mm.

the back lens with its housing comes in at 96 mm and i have yet to get it out of its housing but i'd expect the diameter to be nearly 20mm smaller. will find out how good my guess is tomorrow

can anyone chime in with a comment about the thread diameter of their single focus solution ? i'm looking for something in the ballpark of just over a 100 mm i think or are these lenses still too big for the usual single focus solutions ?

[leslie]

made a leg that will hold the rear anamorphic lens.  its made out of 12mm thick corian as i had it lying around next i will finish the leg holder for the front anamorphic lens

had an x y milling table turn up today plan on using it for various projects the first being  milling some slits in the leg holders for bolts to pass through to the clamps on the rails that aught to help with up and down alignment i hope.

at this point i think with the 12mm corian and the lenses still in their original holders that's its probably heavier than when the original lens  was all together in one piece, but  for the learning experience that's it been its worth it for now. i have also got my eye on a medium format bellows on ebay to go between both the lens and stop stray light entering. im hoping that medium format is big enough not to cause any vignetting between the lenses. as these are pretty big lenses

 

[CfFilmmaker]

Looking awesome! I'm excited to see the finished result!

[leslie]

its a very backyard construction process, no expense spared at the moment ? but i'm not too concerned my boss has a waterjet cutter arriving in the next couple of weeks. so i plan on cutting some interesting shapes out on it as a learning experience in some more appropriate materials during my lunch break of course. i have bought a bellows off ebay a   Mamiya RB67 Bellows lens Hood 150-210-300mm it looks big enough to fit the nap 35 lens and not vignette i hope. well its medium format which is bigger than 35. i know its not a terribly scientific approach more frankenstein than anything. but i think with science you lose alot of the magic in the transmutation process ?