Lens ID Help?

[jeremycole]

Hello, all.

I'm new to the forum and just getting my feet wet with vintage Nikon gear.  I recently purchased an old case containing a Nikon F Photomic that contained a couple of lenses, including the tube in the attached image.  I'm wondering if anyone here might know what this is for? As you can see in the images, it has a tiny lens at one end and standard F mount on the other.  The lens is threaded around the outside (perhaps for an EL-Nikkor?) and behind that there is a ring that can be turned to adjust for distance.  There is a little cut out in the ring allowing markings in feet to show through. The etching around that cut out says, "INF TO ____ FT."  A fixed arrow just behind the ring indicates corresponding f/stops.

Thanks in advance for any light you can shed on this mystery lens!

Best,

Jeremy

[Bjørn Rørslett]

The mount threads could be C-mount. My guess this is a setup for hooking up a camera to a microscope. Or a makeshift "loupe" arrangement for high-magnification photography.

The lens might well be a cine lens refitted to a specific purpose.

[Akira]

The lens appears to be reverse-mounted for larger-than-life macro photography...

Can you remove the lens from the black tube by rotating it counter-clockwise?

[jeremycole]

Thanks guys. 

I think you're probably right.  Microscope or macro makes sense.  There were also some extension tubes and doublers in the case so it looks like the owner was interested in close up photography.

In answer to your question, Akira, it looks like there are two flat faces to the lens just above the threads. Looks like I could put a wrench on there and remove it from the tube. 

[Akira]

Jeremy, thanks for the details.  If it is difficult to remove the lens just like you would do with the screw mount ones like M42 or M39, maybe you'd better leave it as it is.  The wrench should be used only when you are sure that the lens doesn't work...

[ColSebastianMoran]

"wrench..." 

OK, but I suggest care and moderate force.

Looks like three phillips screws holding the last part to the longer tube. Take these out and you might see the front face of the lens.

I had one of these rigs. Recovered a good, perfectly good, 100mm Leica bellows lens once I got it apart.

[jeremycole]

Thanks again for your replies and apologies for the long delay in responding. I don't think I have my settings set correctly to receive notifications.  I'll look into that.

In the meantime, I did remove those screws and could get the lens to turn by hand but it just seems to be spinning in place (i.e. the plate it's connected to spins but the lens itself will not turn in the threads).  I also shone a flashlight in the tube and can see that it looks like an ordinary lens that has been reverse mounted.

About that dreaded wrench... you might be able to see two small, flat faces on the threaded bit between the rear element (facing outward because it's reverse mounted) and the body of the lens. I'm guessing that this is how the lens is attached/detached.  That'll be my next line of attack (gently, of course). If anyone here is familiar with that process all tips are welcome! If successful, I'll post a pic of the lens once it's removed.

Best,

Jeremy

[ColSebastianMoran]

In a similar situation, I took a hacksaw and cut off the metal tube. Carefully, of course.

[jeremycole]

Well, I solved this mystery.  The reason I couldn't get an image in the finder at first was that 1) I needed the lens opened up fully, 2) needed bright light, and 3) the point of focus was about 2mm in front of the lens. 

My subject was a coin and the lens gave a nice sharp close up view (or is a reversed lens technically macro?) about 5mm across or so. The only trouble was that despite being on a tripod and using the camera's timer to take the shot (Nikon F) the motion of the shutter blurred the image! I guess I'll need to rest the tube on something like a sandbag to damped that next time.

[Bjørn Rørslett]

Use mirror lock-up ad a flash.