I presume for Nikon rangefinder:
http://cgi.ebay.co.uk/NIKKOR-O-55MM-F-1-2-SCREW-MOUNT-NO-722249-POUCH_W0QQitemZ190135230062QQihZ009QQcategoryZ4855 6QQrdZ1QQssPageNameZWD2VQQcmdZViewItem
I also presume it doesn't fit LTM (39 mm)? Very odd-looking thread mount.

Regards,

David

http://homepage2.nifty.com/akiyanroom/redbook-e/repro/crtface2.html

It's a macro. You could put it on bellows for that. Probably not a bad general purpose lens but maybe it could have some yellowing. You'll have to research that.

http://homepage2.nifty.com/akiyanroom/redbook-e/repro/crtface2.html

It's a macro. You could put it on bellows for that. Probably not a bad general purpose lens but maybe it could have some yellowing. You'll have to research that.

Are you sure? It's a f1.2!

Regards,

David

I'm always amazed by the lenses that come out of the woodwork.

Could this be for a Nikon Rangefinder camera from the 1950s?

David, these CRT lenses are always fast and most manufacturers made them. I have an f1.9 Dallmeyer 80mm. They rarely stop down further than f11 - f16 as in many cases they would be used at full aperture. The older CRT tubes were often covered by a green screen and the screen brightness is not intense.

They are optimised for close macro work and often have poor coverage focussed at infinity.

Ian

Are you sure? It's a f1.2!

I think that may be one of the "magic" ones that isn't f:1.2 at infinity, but does f:2.4 effective at 1:1. The only way to mark the barrel is with f:1.2, even if the front lens is too small for that aperture!

Ole, the lens isn't designed for 1:1 that would be a very small CRT screen, the site Keith posted the link for states:

"Within the 24x36 mm film, vignetting is insignificant in CRT reproduction applications.
It should be noted that at its standard magnification of 1/5X the nominal F1.2 speed of the lens is reduced to F1.4."

The use of the phrase "vignetting is insignificant" is important, its unlikely the lens could actually focus at infinity on a Leica thread camera because of the lenght of the lens mount, and this mount would itself cause vignetting at infinity.

These lenses make great loupes.

Ian

You're right Ian - I was thinking of the "magical" f:1 macro which gives f:2 effective at 1:1. :)

If they're meant for CRT readouts, the speed of the lens would be very advantageous, those screens can be pretty dim. But these obviously weren't meant to be shot at f/1.2 or at infinity focus. I also thought that maybe the thing is intended to go on bellows, the mount reminds me of the bellows-Nikkor macro. Now with bellows, obviously, there is bellows factor to consider, so you usually want as fast a lens as possible, to begin with.

Given its intended purpose, I would guess (guess) that the bokeh and colour rendition will be noticeably inferior to other fast primes. But who knows, it might be an interesting lens for portraiture.

Ian is right- nice loupe! Also I think some of these somewhat inferior fast primes find a second life on APS digital, where VF brightness can be a problem and the performance away from the center isn't so important. The normal Nikkor 50/1.2, for example, is soso on film, but on digital it's a nifty fast portrait lens.

I think this is the Oscilliscope Nikkor lens. The odd thing is that I only knew of a 50mm f1.2 oscilliscope lens, which would make this 55mm an odd one.

You might want to search for Red Book Nikkor, which should lead you to a Japanese website. They would likely know the identity better.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

Thanks to all for info - I wanted to find out what it was before the auction closed. It sold for nearly $500 - hope the buyer isn't disappointed!
Someone here has used a lens of this kind for pictorial purposes:
http://www.pbase.com/regit/crt_nikkor
As expected, fuzzy when used outside its narrow working parameters.

Regards,

David

Gordon, that link Keith posted is the Red Book Nikkor page for this exact lens.

Keith's link (http://homepage2.nifty.com/akiyanroom/redbook-e/repro/crtface2.html)

Ian

Only the Nikkor O-Scope lens commands a premium. It looks beautiful, I do not have one. You can pick up other super-speed close-up lenses for cheap. Wollensak made a high quality 50(ish)/1.2 for use in Tektronix O-Scope cameras. They normally were used with Polaroid film, so they have a good back-focus.