Question: When is 112mm not 112mm?

[Steve Goldstein]

Answer: When Schneider's published literature says the accessory thread of the Center Filter IVb is 112mm x 1.5mm.

Explanation: Two B+W 112mm filters I recently acquired measure 111.9mm across the 1.5mm-pitch male threads, which is close enough in my book given they're surely not cut for 100% engagement. They will not screw into my CF IVb, although they will screw into each other in either order (implying both male and female threads are good). The Center Filter's outside diameter is almost exactly 112mm, meaning its female thread is necessarily less and thus too small to accept standard 112mm filters.

It's surprising that a firm that's been around as long as Schneider would make such a doofus error. And I won't even mention the 112mm Kenko filter that has 112mm threads, but with 1mm pitch - what were they thinking? Thankfully I have alternatives. And I get to sell the useless-to-me 112mm filters - it always makes my wife happy to see the occasional box leave the premises.

[Michael R]

That’s strange. And B+W has been part of Schneider since the mid 1980s.

[Steve Goldstein]

Michael, thank you. I knew B+W was part of Schneider but didn't know when that happened.

[ic-racer]

So B&W customer service has returned them to you claiming both that they are not counterfeit and that they are correctly manufactured?

[Steve Goldstein]

I have no plans to go to that much trouble. The B+W filters certainly appear genuine when compared with the (many) B+W filters I own in various sizes and came in what appears to be a genuine blue Schneider soft case with genuine-appearing factory labels. Measurements by me and by my machinist confirm the dimensions of the 112mm filters.

I suppose it's possible the CF is a fake, but that's a lot of trouble to go to for such a low-volume item. I'm not going to lose sleep over it, I have other filtering options that are actually easier than tracking down 112mm black-and-white contrast filters at non-nosebleed prices.

[Tin Can]

Same problem with my SAE 16" Kodak lens

I was able to find a 122 mm mismatch that does snug up a decade ago

Now they have more variation

https://www.bhphotovideo.com/c/product/936683-REG/b_w_66_1070050_122mm_clear_007_filter.html

[David Lindquist]

What an irritation. Back in 2016 I bought two Formatt-Hitech 95 mm contrast filters to use with the Linhof 001933 filter holder which takes 95 mm x 1 mm pitch filters. The Formatt-Hitech filters did not fit, having a finer thread pitch, probably 0.75 mm. Unfortunately for me these were special order and not returnable. I eventually modified them to fit the M105 x 1 Sinar Norma filter holder.

95 mm filters from B+W, Helioplan, Tiffen and Hoya all fit the Linhof holder.

David

[Michael R]

Incidentally there is a B+W filter authenticity checker: https://schneiderkreuznach.com/en/authenticity-check

[Axelwik]

Is the CF thread damaged or slightly bent? Do other filters of the same diameter fit?

[Jim Andrada]

Well I have a Linhof M679 with the Linhof adapter to mount Technika lens boards, but my genuine Linhof Technika lens boards don't fit. I have to take a piece of fine 600 grit sandpaper and lengthen the center slot a mm or so before they fit. It's not just filters...

[Steve Goldstein]

Is the CF thread damaged or slightly bent? Do other filters of the same diameter fit?

No, and no. The outside diameter of the CF is almost precisely 112mm. It is physically impossible for something with 112mm threads to fit.

[maltfalc]

i would probably just etch the threads until they fit, but i'll use any excuse i can get to start a new diy project.