Seiko 'B' Shutter - 48MT lensboard

Hi,

What is a Seiko 'B' shutter, and is it 48mm. in diameter?

I have tried to find information on the internet, but not
much has appeared.

Could you please tell me a bit about this shutter and the
lensboard needed to mount it?

Thank you in advance, kind regards!

I answered your question on the LF photo forum; shutterfinger kindly provided the link here also.

When KEH lists a large format lens, they usually write something like "Seiko B 48MT" or "Copal BT 42MT." That's not a formal name for the shutter, it's just information. "Seiko B 48MT" means that it's a Seiko shutter, it has a B setting (some shutters have both B and T), and it needs a 48mm hole in the lensboard. A normal #1 shutter needs a 42mm hole in the lensboard. Apart from the different thread sizes it operates like any other leaf shutter.

Hi,

Thank you for your messages : )!!!

In that case a '48MT' would need a
48mm. hole.

Thank you again, kind regards!