Seiko Shutter Sizes

[fosforforfosfor]

Hi everyone,

I am looking for Seiko Shutters in size #1, but noticed the inscriptions on the shutters confuse me a lot. Is anyone there on this forum who can help me?

So the thing that confuses me is that a lot of the Seiko shutters have an inscription saying LS1, or LS22. Do these signify the size of the shutter? And what’s the easiest way to figure out what size the shutter is (when I don’t have physical access to the shutter to actually measure the threads)?

Thanks!

[Steve Goldstein]

The LS numbers refer to the specific Fujinon lens that was originally mounted in the shutter. According to info I've slowly assembled over the years, LS1 matches to the 150mm f/6.3 and LS22 is, I believe the 75mm f/8 Fujinon-SW, both of which were in Seiko 0 shutters.

[fosforforfosfor]

The LS numbers refer to the specific Fujinon lens that was originally mounted in the shutter. According to info I've slowly assembled over the years, LS1 matches to the 150mm f/6.3 and LS22 is, I believe the 75mm f/8 Fujinon-SW, both of which were in Seiko 0 shutters.

Oh, good to know! Any idea which LS markings match with size #1 shutters? That would make my search a bit easier!

Thanks! 🙏

[Steve Goldstein]

Oh, good to know! Any idea which LS markings match with size #1 shutters? That would make my search a bit easier!

Thanks! ��

My list isn't exhaustive, it's compiled from examining photos of lenses on eBay as they come along and I remember. The only ones I have noted as in Seiko 1 shutters are:

180mm f/5.6 (marking LS23)
250mm f/6.7 (marking LS24)
180mm f/5.6 SF (marking LS43).

Remember that aperture bands are specific to lenses and focal lengths and the indicated aperture won't be correct for other than the original lens type. I believe focal length plays a bigger role here than lens design. The error gets progressively bigger the further away the focal length is from the one that originally came in the shutter.

[Mick Fagan]

My Fujinon SW f/8 90mm in a No. 0 Seiko shutter, is marked LS17, for what it is worth.

[Vaughan]

Note that Seiko 1 shutters are very different to Copal 1 shutters in the lens cell thread size, and the size of the hole in the lens board. For instance, the front and rear cells of a Fujinon W 180mm f5.6 lens in Seiko shutter are not interchangeable with those for a Copal shutter: I have both.

The easiest way to remember shutter size is: any f5.6 lens 150mm or shorter will be in a Size 0 shutter; any f5.6 lens longer than 150mm will be in a size 1 shutter. Anything 300mm or longer will probably be in a Copal 3 shutter.

I made a table of Seiko shutter labels, it's not complete.

256044

[Dan Fromm]

Note that Seiko 1 shutters are very different to Copal 1 shutters in the lens cell thread size, and the size of the hole in the lens board. For instance, the front and rear cells of a Fujinon W 180mm f5.6 lens in Seiko shutter are not interchangeable with those for a Copal shutter: I have both.

That's nice, but what are the sizes?

[Vaughan]

Seiko 1 shutter OD of rear cell thread = 42mm
Seiko 1 shutter OD of front cell thread = 42mm

Seiko 1 shutter lens board mounting hole = ~47mm

[Dan Fromm]

Thank you, sir.

[fosforforfosfor]

Thanks for the small list! ��

Yeah, I am aware of the difference in sizing between Copal and Seiko shutters, that’s why I am looking for a Seiko #1 shutter. With all info provided by all of you, I can start my search properly. ��

[Vaughan]

The shutters themselves are largely the same. The f-number scale is held on with three or four small screws so they can (in theory) be interchanged.

Some Seiko 0 shutters have self-timers and different sync socket designs, the f-number plates between these are not interchangeable.