Bronica Nikkor-H 50mm 3.5

[Uglee]

This is for the Nikkor-H 50 3.5 used on a Bronica S2a.

I have reached a dead end in trying to remove the second lens from the front to get to the fungus on the surface of the third lens.

The front lens comes off easily, however the threaded filter ring does not move at all. I tried to remove the outer surface trim ring hoping that i would find grub screws under it but it is designed to fit in a groove. It will spin but to remove it would require cutting or seriously deforming it. There for I disassembled the lens from the rear, removing the three rear lenses but that led to a dead end.

If anyone has worked in this lens, any insight on how can I get the 2nd lens off? Or can someone direct me to a schematic diagram of this lens?

Any help is appreciated.

David L.

 

[Phil_F_NM]

Have you tried a suction cup?
Are you sure that the element is a single, not a group with another element that could be grub screwed farther back?
Some of the old Bronica Nikkors sit cemented in metal sleeves that are threaded into the barrel. You may try this idea as well but realistically, I'd put the lens back together and shoot it. Spots on the back of the second element won't really affect imaging and this lens is inexpensive enough that you could find another more easily and cheaply than getting the cleaning done. It's a spectacular optic! Do you have the much-harder-to-find Bronica square hood?

Phil Forrest

 

[Uglee]

Phil,

The element is a single and the fungus is on the outer surface of the third lens. It appears that the lens may be cemented in place. It has a collar circling around the front edge. I will try a suction cup, perhaps it is screwed in? I have reassembled it and will see how badly the spots affect the image.

I did not receive the square hood with this kit but it did have 75mm 2.8 with hood, 200mm 3.5, 6x6 and 645 film backs and assorted 82mm filters for the 50.

 

[chalky]

front element

front element

Hi,
apologies for jumping into this thread. I have the same lens with fungus on the inside of the front element, I'm not an expert at taking lenses apart, but can see that you guys know how to take the front element off, and was hoping someone could jump in and give me a couple steps of how to do that? Many thanks,
Matt

 

[Uglee]

The front element is held in place by the black trim ring with the name on it. Since it does not have holes or slots for a spanner wrench, you will need to find something that will suffice as a friction tool to unscrew the ring. I used a strip from a giant rubber band that came off of a bunch of broccoli from the market. It unscrews counter clockwise, the lens will then drop out. If the fungus is under the second element as mine then we are both in the same boat. Good luck.

 

[chalky]

Thank you for your reply, I will try that and report back.

I did also try and get to it from the rear elements but only managed to get to the third lens then was stuck and could get no further.

I have seen a lens schematic for this lens somewhere, if I stumble across it again I will post it here.

Thanks again

 

[chalky]

I'm struggling to get the front ring off using friction alone but will keep trying.

Here is a very rough diagram of the lens, might not be the detail you are looking for though...

http://nikomat.org/priv/camera/mednikkor/bronica/brolens/brolens.html#200-1