ID a screw mount for me.

asim18 · 8 Sep 2009 at 22:54

Hi, I've picked up an ancient lens which my brother threw away.

It's a screw mount lens and it's diameter is about 41.5 mm (measured with a ruler lol). Is this an M42 mount?

I want to buy an adapter so I can use it on my d40x. I just want to make sure I get the right adapter.

Also, will it work ok with a cheap 2x converter? I saw some on the bay and it's very tempting.

Thanks.

Edit: I can take some pics of it, if it helps.

Dunks · 8 Sep 2009 at 23:15

If you measured it at 41.5mm, then yes, it'll be M42 fit. You can get M42 -> Nikon adapters on the bay.

asim18 · 8 Sep 2009 at 23:31

Ah, thanks for the reply mate.

Also, what about the extender? There's a 3x M42 converter on the bay for £14. Can I use the extender and the adapter together? Will there be any problems with the focusing?

Snapshot · 9 Sep 2009 at 06:25

asim18 said:
Will there be any problems with the focusing?

Yes, it'll be very dark looking through the lens and teleconverter combination so it'll be difficult to see if your subject is in focus. A 3x teleconverter will cost you three stops. You haven't said what the lens is but teleconverters work best with longer lenses. OTOH a cheap 3x converter from the bay is likely to be so poor optically that it probably doesn't matter.....