Nikon BD threading

mgoodm3 · Post by **mgoodm3** » Fri Mar 26, 2010 1:59 pm

I just got a Nikon BD 5/0.1 210/0 objective and was expecting the BD thread to be M25 as I have seen listed on other Nikon objectives. It doesn't fit on the M25 adapter that I got for it - too big.

It is M26. I have a M26 x 36 TPI adapter that works quite nicely with it.

Just an informational posting.

ChrisR · Post by **ChrisR** » Fri Mar 26, 2010 4:57 pm

I believe the later, perhaps Infinity era BDs are bigger again.

PauloM · Post by **PauloM** » Fri Mar 26, 2010 7:02 pm

mgoodm3,
Is this the M26 adapter you have?

Nikon's infinity non-BD (biological) objectives are M25x0.75.

Chris, are you sure about that? I thought all BDs were the same thread.

P

mgoodm3 · Post by **mgoodm3** » Sat Mar 27, 2010 8:02 am

http://www.edmundoptics.com/onlinecatal ... StartRow=1

ChrisR · Post by **ChrisR** » Sat Mar 27, 2010 10:53 am

Chris, are you sure about that? I thought all BDs were the same thread.

I had some adapters made. They fit an Infinity BD but are about 1mm too big for my 210s, which measure 26mm o/d.

I see Thorlabs do a few, including 27mm but not 26.
http://www.thorlabs.com/NewGroupPage9.c ... up_ID=1747

mgoodm3 · Post by **mgoodm3** » Sat Mar 27, 2010 11:06 am

I got my M25 from Thor labs. Got nothing to use it on at present...

morfa · Post by **morfa** » Sat Mar 27, 2010 1:09 pm

PauloM wrote:mgoodm3,
Is this the M26 adapter you have?

That is the one I have – a perfect fit with a BD M Plan 10x 0.25 210/0.

(Less than perfect buying experience though. The seller (same as in the listing above) sent me the wrong item twice. It took over a month, a lot of email diplomacy and even some additional payment before I received it)

BD M Plan fitted to a RMS iris mount via 1"->RMS adapter.