Trouble finding a filter or step-up ring for Bronica Nikkor 40/4 lens?

[John Gaasland]

I have been trying to find a step-up ring for my Bronica Nikkor 40mm/f4 lens. It takes a 90mm filter which only Bronica made and cannot be found. I wanted to use a 90-95 step-up ring to use a filter and a rubber lens hood that I have already bought. I've bought two step-up rings from different sources, neither of them will fit. The lens cap fits, so the threads are fine. I measured the lens cap threads and it looks like 1.0mm. The ring seems like it's a little different. Any ideas? Thanks, John.

 

[gone]

Lens cap are sorta roughly one size or another, not necessarily exact sizes, because they're plastic and need to adjust in or out to get mounted on a lens. If you know for sure that the lens takes a 90mm filter, you still may have an issue w/ thread pitch because that needs to be measured at the lens or at your 90mm filter, not the lens cap.

 

[cramej]

Lens cap are sorta roughly one size or another, not necessarily exact sizes, because they're plastic and need to adjust in or out to get mounted on a lens. If you know for sure that the lens takes a 90mm filter, you still may have an issue w/ thread pitch because that needs to be measured at the lens or at your 90mm filter, not the lens cap.

Bronica S2 and related lens caps are threaded so it would be the same as the filter size and pitch.

 

[David A. Goldfarb]

I had that lens—great lens—for my S2A, and I think what I did was to use 100mm gel filters and a Lee filter holder that attached with a rubber band.

 

[macfred]

https://www.ebay.de/itm/142682046262

 

[AnselMortensen]

Try www.filterfind.net

 

[John Gaasland]

The lens cap is Bronica and it's aluminum, so I think the threads are fine. I could have SK Grimes make a step up ring but that might be more than the lens is worth. Thanks, John.

 

[John Gaasland]

https://www.ebay.de/itm/142682046262

I have bought two rings from different vendors with those same specs and they did not fit...John.

 

[Dan Daniel]

So grind down the threading on the bum step up ring and epoxy it place. Turn the lens into a 95mm standard threading using the ring. Solve this mess!

 

[John Gaasland]

But, resale value!!! J

 

[moto-uno]

You could probably have similar success using silicone seal to hold it . Pretty large surface area , so the silicone should
be strong enough . Peter

 

[David A. Goldfarb]

That lens is the whole reason for the early Bronica falling mirror design, and later the split mirror--so the lens could protrude into the mirror box and reduce the amount of retrofocus correction required. I wouldn't epoxy anything to it.