Filter thread question

[Retro-Grouch]

I recently purchased a wonderful 40mm Nikkor for my Bronica S2. The down side is that it has 90mm filter threads. Good luck finding anything in that size; from what I can determine, Bronica produced no other filters besides the L1A skylight in 90mm, nor did they make a lens hood (much needed for a 10-element single coated lens). Searching on eBay for some kind of step-up ring gives me one result, but the thread is 90x1 tpi. I believe that a pitch of .75 is pretty much universal, and I assume that's what's on my lens. Will the step-up ring work, or will it bind? Thanks in advance for any answers from anyone with more expertise in these matters.

 

[shawn]

I saw elsewhere that the step up ring doesn't fit the 40mm.

This might be a 3d printer solution. I'm thinking an adapter that slips over the outside the lens (it is about 92.5mm) and it holds a 95mm or 105mm filter in it (or at least the ring) rig and any other fiters would screw into that or each filter gets its own adapter. 105 would probably give more flexibility with regards to doubling up on filters while potentially avoiding vignetting, 95 would be a little smaller and cheaper.

 

[Retro-Grouch]

I saw elsewhere that the step up ring doesn't fit the 40mm.

This might be a 3d printer solution. I'm thinking an adapter that slips over the outside the lens (it is about 92.5mm) and it holds a 95mm or 105mm filter in it (or at least the ring) rig and any other fiters would screw into that or each filter gets its own adapter. 105 would probably give more flexibility with regards to doubling up on filters while potentially avoiding vignetting, 95 would be a little smaller and cheaper.

Thank you to our resident Bronica expert! Now, if I only had the savvy and the hardware to do 3D printing...
If I fall as madly in love with this lens as I expect, I might look into having one custom made by S.K. Grimes in Providence, but I'm sure it wouldn't be cheap. At least the lens came with a mint skylight filter and cap; that's a big chunk of glass to leave exposed to the slings and arrows of outrageous fortune.

 

[shawn]

Ahh, but I have the Bronica 40mm with original cap but no filters for it. And the 3d design and printing ability.

I doubt I'd get a bunch of filters but am thinking either a red or yellow would be fun. Probably red since the perspective is pretty dramatic anyway. A cheapo no name 95mm red filter is around $30 on ebay. Putting that into a slip on adapter for the 40mm should be pretty easy.

Could take the same slip on part and design a hood too. Would be friction fit but with how light it would be shouldn't be a problem.

Hmmmmm......

Have you shot the 40 yet?

 

[Retro-Grouch]

Ahh, but I have the Bronica 40mm with original cap but no filters for it. And the 3d design and printing ability.

I doubt I'd get a bunch of filters but am thinking either a red or yellow would be fun. Probably red since the perspective is pretty dramatic anyway. A cheapo no name 95mm red filter is around $30 on ebay. Putting that into a slip on adapter for the 40mm should be pretty easy.

Could take the same slip on part and design a hood too. Would be friction fit but with how light it would be shouldn't be a problem.

Hmmmmm......

Have you shot the 40 yet?

Yes, but only a couple shots on a roll that hasn't been processed yet. Oddly, I've really enjoyed using it. I had a SWC about 10 years ago, and hated it; not much difference in the coverage, and the Hassie of course has the better lens, but the awkwardness and inconvenience (tripod only) when I wanted reflex viewing was the deal breaker. Not to mention that awful optical finder. But after all, the Hasselblad is the foolish man's Bronica. 😉

 

[shawn]

It is a fun lens to shoot, I really like the WLF with that perspective. Easier for me to get lower angle shots (I'm 6'5") and see the framing.

The SWC is one I have considered many times. I haven't done it as I know the finder would bug me and I probably wouldn't shoot it enough to justify the cost. The Bronica with the 40 is great. For digital, the fp L in 1x1 with the 10-18 can do the same FOV as the Hassy and go much wider and is tiny compared to the SWC.

 

[shawn]

I doubt I'd get a bunch of filters but am thinking either a red or yellow would be fun. Probably red since the perspective is pretty dramatic anyway. A cheapo no name 95mm red filter is around $30 on ebay. Putting that into a slip on adapter for the 40mm should be pretty easy.

Could take the same slip on part and design a hood too. Would be friction fit but with how light it would be shouldn't be a problem.

Hmmmmm......

@Retro-Grouch

Building on this....




This is a friction fit over the barrel of the Nikkor 40mm. It has a stopper that prevents it from going to far.

The larger cutout is sized as a drop in for 95mm filters. (100mm diameter, 7mm deep)




The four holes are for magnets (delivered tomorrow) which will hold this is place...




.. which in turn holds the filter in place.

I originally made the hood round (160mm diameter) but it looked like it might hard vignette in the extreme corners so relofted it as a square hood. Printing now. Will also probably make a non-hood magnetic retaining ring to just hold the filter in place for when I don't want the hood.

 

[shawn]

The square hood is large. Just taped together as I don't have the magnets yet and will likely be slimming down the adapter a little more anyway.

 

[shawn]

Here is a quick movie showing it with the magnets installed.

 

[Retro-Grouch]

Here is a quick movie showing it with the magnets installed.

Genius! I was shooting outdoors with that lens yesterday, and, if the sun was at anything less than a 90 degree angle, I got ghosting. I also have a kluged-together hood in the works, but it's not the elegant design you've created.