Odd-sized filter thread?

Thwyllo · Aug 30, 2023

I recently bought a job lot of mixed filters of various sizes which includes a couple of Cenei supplementary 'lenses' (1 and 2 dioptre) which mount with a 35mm thread but I'm damned if I can find any camera or lens with a filter thread of that size. Anyone got any ideas what they might have been for?

xkaes · Aug 30, 2023

They could be Series "filters" -- V perhaps?

Thwyllo · Aug 30, 2023

xkaes said:
They could be Series "filters" -- V perhaps?

Hmm possible...but I found this on ebay and the two filters I have are boxed and marked exactly the same as this one except for the +1 and +2 to indicate the dioptre strength. It's clear they were intended for something with a pretty small lens and presumably quite old; I just wondered what! But thanks for your kind response.

Ceneiplan Germany R1.5 skylight filter for 35 mm filter thread (very good) | eBay

Find many great new & used options and get the best deals for Ceneiplan Germany R1.5 skylight filter for 35 mm filter thread (very good) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

DWThomas · Aug 30, 2023

Series filters don't normally have threads, just a plain rim. They are typically used with an adapter (often with slip-on spring fingers) on the camera and a screw-in retaining ring. There are/were often sunshades that had the retainer ring structure built in so as to reduce stacking build-up.

Series V were 30.2 mm and Series VI were 41.3 but that's the OD of the metal rim, not a thread. There is a passing indication of a Series 5.5 as 35.9 mm, but can't say I've ever seen one.

I see 35.5 mm filters shown new on B&H -- wonder if the ones you show just skipped the .5. There aren't many filter threads spec'ed to nn.5 mm.

Alex Benjamin · Aug 30, 2023

Tiffen has a pretty extensive list on its website. Some 35.5mm, but no 35mm. Must be for a long-gone camera.

https://tiffen.com/pages/filter-to-lens-chart

Alex Benjamin · Aug 30, 2023

Cenei seemed to have specialized in odd filter thread sizes. Just found a 29.5mm.

Ceneiplan 29.5mm UV Filter B+W film 35mm | eBay

This is a Ceneiplan 29.5mm UV filter.No issues.

www.ebay.com

BrianShaw · Aug 30, 2023

29.5mm fit Kodak Retinas. What’s really odd is that Kodak called that 32mm

MattKing · Aug 31, 2023

BrianShaw said:
29.5mm fit Kodak Retinas. What’s really odd is that Kodak called that 32mm

Probably because that was the size of the push on Series filter adapter that one would/could use the filters with.

BrianShaw · Aug 31, 2023

MattKing said:
Probably because that was the size of the push on Series filter adapter that one would/could use the filters with.

At one time, for sure.

But for Kodak "32mm" filters in the Retina II/III c/C era the threads are the smaller (real) size, and the outside diameter was the larger (Kodak nomenclature) size. This is perhaps the only really nucklehead thing I can think Kodak to have done. A great marketing ploy, perhaps?

Ian C · Aug 31, 2023

The B&H site in NYC lists circular filters in sizes 34 mm and 35.5 mm. I wonder if the “35 mm filter” might be 35.5 mm whose size statement has been shortened to “35 mm.”

It would be useful to have someone measure the OD (Outside Diameter) of the thread with a micrometer or dial caliper.

A male 35.5 mm thread would measure slightly less than the named size, since the OD of male thread is marginally smaller than the nominal diameter for the necessary assembly clearance. For example, a 40.5 mm x 0.50 mm filter I measured has an outside diameter of 40.39 mm, or 0.11 mm smaller than the nominal diameter.

Using this differential, the named diameters and the likely measured diameters of three sizes close to 35 mm would be:

Nominal 34 mm, likely actual diameter 33.89 mm

Nominal 35 mm, likely actual diameter 34.89 mm

Nominal 35.5 mm, likely actual diameter 35.39 mm

If the size of the filter actually is 35 mm, it would be interesting to learn of the camera for which it was made. I poked about on the Internet but couldn’t find an answer.

Thwyllo · Aug 31, 2023

DWThomas said:
Series filters don't normally have threads, just a plain rim. They are typically used with an adapter (often with slip-on spring fingers) on the camera and a screw-in retaining ring. There are/were often sunshades that had the retainer ring structure built in so as to reduce stacking build-up.

Series V were 30.2 mm and Series VI were 41.3 but that's the OD of the metal rim, not a thread. There is a passing indication of a Series 5.5 as 35.9 mm, but can't say I've ever seen one.

I see 35.5 mm filters shown new on B&H -- wonder if the ones you show just skipped the .5. There aren't many filter threads spec'ed to nn.5 mm.

No you're right...the only one I know of is the 40.5 that fits Pentax Q lenses among others.

Looks like it has to remain one of life's little mysteries but thank you all for your replies!

abruzzi · Aug 31, 2023

My Schneider 150mm G-Claron has a 35.5 thread, my Schneider Xenar 150mm f5.6 uses a 34mm thread. I have several lenses with a 40.5mm thread, but the only one I remember is my Nikkor-M 105mm ƒ3.5. (these are all view camera lenses.)

Dustin McAmera · Aug 31, 2023

Just to lower the tone, my Lubitel 166B uses a 40.5mm hood.

Dustin McAmera · Aug 31, 2023

Fotoimpex will sell you a 35mm UV filter:

HELIOPAN Filter UV-Haze - Diameter: 35mm - fotoimpex.com analogue photography

Overall the UV-Filter is an outstanding filter universal in use. Not only does the filter help to improve image quality but also is a relatively low cost device when it ...

www.fotoimpex.com

AnselMortensen · Sep 3, 2023

Check with Tim at www.filterfind.net

eli griggs · Sep 3, 2023

Alex Benjamin said:
Cenei seemed to have specialized in odd filter thread sizes. Just found a 29.5mm.

Ceneiplan 29.5mm UV Filter B+W film 35mm | eBay

This is a Ceneiplan 29.5mm UV filter.No issues.

www.ebay.com

IIRC, I have an 25 red in that series size.

Klaus_H · May 31, 2024

BrianShaw said:
29.5mm fit Kodak Retinas. What’s really odd is that Kodak called that 32mm

The 29.5 mm filters for the Kodak Retina had a thread pitch of 0.4, the 29.5 mm filters for the AGFA Super Isolette had a thread pitch of 0.5 mm. They were not interchangeable!

The 32 mm is the dimension for the push on filter.

BrianShaw · May 31, 2024

Klaus_H said:
…

The 32 mm is the dimension for the push on filter.

In the early Retinas that is true. It is not true for the 1950s Retinas. The, Kodak actually labeled the screw-in filters as 32, the OD, when the threads were 29,5 mm.

lobitar · Jun 1, 2024

The Agfa Ambi-Silette has 3 lenses (90mm - 50mm - 35mm) all with 35,5 mm filter thread.

lobitar · Jun 3, 2024

The Bessa 6x9 mod. 1 & 2 uses 35mm. Likewise the Rollop model 1 & 2 (whatever that is?). The Yachica 8 w. 1.4/38mm uses 35mm.
35,5 mm is used by several Zeiss Ikon cameras (like Ikoflex 2a, Ikonta 6x6 & 4x6, Tenax 24x24 and Movikon 8). These are just chance finds, obviously there may be others.

Odd-sized filter thread?

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