Dez
Bodger Extraordinaire
The Nikkor 21mm lens for the RF cameras is a wonder to behold, but there are lots of places in the world where you can buy a house for what you need to pay for one of them. As a result, F-to-S adaptors are really popular items, and lots of people, me included, have bodged them up. A cheap 20mm viewer from an FSU Russar 20mm lens, and you're good to go, as in my icon.
Unlike the RF version, the F version of this lens has a shroud around the rear element which allows it to go into the lens mount in only one position. If you look at the lens mount of a Nikon film camera you will see a little lug at the 11:00 position, just inside the lens flange. It is there specifically to correctly locate this lens, which has a unique breechlock ring to secure it to the F mount. As a result, with the adaptor I made, it was necessary to first fit the adaptor to the Nikon RF camera and only them mount the 21mm lens. If you tried to mate the lens and adaptor to the camera as an assembly, you would mash the shroud into the metal near the film plane.
I discovered that if I remove the shroud, there is enough clearance at the rear of the lens to leave the adaptor on the lens permanently, and mount it on my SP just like any other RF lens. My question is, is that going to be possible as well for any other Nikon RF body?
I think for my next project, I will build an F-S adaptor which is designed to be attached permanently to the 21mm lens, and which will allow it to be rotated so that the infinity mark is on top where it belongs. In the F implementation, the infinity index, for some unfathomable reason, is at about the 1:30 position. It should be a lot simpler than the one I did before, and maybe I can finally make good on my promise and make up a few for people on RFF.
Cheers,
Dez
Unlike the RF version, the F version of this lens has a shroud around the rear element which allows it to go into the lens mount in only one position. If you look at the lens mount of a Nikon film camera you will see a little lug at the 11:00 position, just inside the lens flange. It is there specifically to correctly locate this lens, which has a unique breechlock ring to secure it to the F mount. As a result, with the adaptor I made, it was necessary to first fit the adaptor to the Nikon RF camera and only them mount the 21mm lens. If you tried to mate the lens and adaptor to the camera as an assembly, you would mash the shroud into the metal near the film plane.
I discovered that if I remove the shroud, there is enough clearance at the rear of the lens to leave the adaptor on the lens permanently, and mount it on my SP just like any other RF lens. My question is, is that going to be possible as well for any other Nikon RF body?
I think for my next project, I will build an F-S adaptor which is designed to be attached permanently to the 21mm lens, and which will allow it to be rotated so that the infinity mark is on top where it belongs. In the F implementation, the infinity index, for some unfathomable reason, is at about the 1:30 position. It should be a lot simpler than the one I did before, and maybe I can finally make good on my promise and make up a few for people on RFF.
Cheers,
Dez
KHW
Established
I have the same Nikon 21 for F and also thinking to buy a Consina FS adaptor. Does it work?
James24
Well-known
Dez
Bodger Extraordinaire
Building an F-S adaptor
Building an F-S adaptor
I posted some information a while ago on how to build the adaptor, available at:
http://www.rangefinderforum.com/forums/showthread.php?t=91022
The most aggravating problem with this device is that the latches for the F and S mounts are almost exactly on top of each other at the 3:00 position of the lens mount, and there just is not enough space to provide both latches. I am going to make a new version where the F mount is rotated a few degrees CCW looking at the front, so they will not interfere. This will result in having the index mark of the 21mm lens closer to the top, and the index of other lenses to be at the 11:00 position instead of 12:00. (I use my adaptor to mount the 8mm f2.8 fisheye lens too: totally impractical but fun.) I may leave out the locating lug for the 21 mm lens in this design as it is difficult to make and position exactly, but it will definitely necessitate removing the shroud before using the lens with the adaptor.
Maybe we should start a thread for the most wildly impractical lens attached to a Nikon RF. I will submit a picture of my SP with the old 50-300 zoom!
But first I need my garage to thaw out. Winter in Minnesota is no joke.
Cheers,
Dez
Building an F-S adaptor
I posted some information a while ago on how to build the adaptor, available at:
http://www.rangefinderforum.com/forums/showthread.php?t=91022
The most aggravating problem with this device is that the latches for the F and S mounts are almost exactly on top of each other at the 3:00 position of the lens mount, and there just is not enough space to provide both latches. I am going to make a new version where the F mount is rotated a few degrees CCW looking at the front, so they will not interfere. This will result in having the index mark of the 21mm lens closer to the top, and the index of other lenses to be at the 11:00 position instead of 12:00. (I use my adaptor to mount the 8mm f2.8 fisheye lens too: totally impractical but fun.) I may leave out the locating lug for the 21 mm lens in this design as it is difficult to make and position exactly, but it will definitely necessitate removing the shroud before using the lens with the adaptor.
Maybe we should start a thread for the most wildly impractical lens attached to a Nikon RF. I will submit a picture of my SP with the old 50-300 zoom!
But first I need my garage to thaw out. Winter in Minnesota is no joke.
Cheers,
Dez
Dez
Bodger Extraordinaire
REALLY scarce
REALLY scarce
The beautiful little Cosina adaptor is a real gem if ever you can find one, but they are in the same rarity class as honest politicians. But like said politicians, they cost a lot more to buy than you would ever believe, if ever you find one. Also like H.P.'s, while I have seen an occasional picture, I have never actually encountered one!
Cheers,
Dez
REALLY scarce
The beautiful little Cosina adaptor is a real gem if ever you can find one, but they are in the same rarity class as honest politicians. But like said politicians, they cost a lot more to buy than you would ever believe, if ever you find one. Also like H.P.'s, while I have seen an occasional picture, I have never actually encountered one!
Cheers,
Dez
KHW
Established
I found the gem today!!! I put the Nikkor 21 on my SP now. No rangefinder couple but I consider my collection is now completed, with even with the Olympic 50/1.4!! No modification needed!
KHW
Established
mynikonf2
OEM
Tom A
RFF Sponsor
I use a F-S adapter on a BD S2 as it has a very dim rangefinder patch - and the 21f4 F lens does not couple anyway. One advantage is the 52mm filter size too.
Yes, the VC S-mount 21f4 is better and smaller. But the old Nikkor 21f4 has a distinct look to it. Very 60's - edge fall-off and sharp center (somewhat akin to a Super-Angulon 21f3.4)
I also have the 21f4.5 Biogon (Contax mount) which is another of the great oldies - though you cant see any f-stop numbers. Miniscule black script on bright chrome!!!!!
Yes, the VC S-mount 21f4 is better and smaller. But the old Nikkor 21f4 has a distinct look to it. Very 60's - edge fall-off and sharp center (somewhat akin to a Super-Angulon 21f3.4)
I also have the 21f4.5 Biogon (Contax mount) which is another of the great oldies - though you cant see any f-stop numbers. Miniscule black script on bright chrome!!!!!
KHW
Established
This is a nicely done repaint SP. I have several 21 Biogon and use them on SP for several years. And this is the first time to actually mount this 21/4 on Nikon RF. Willl try it tomorrow.
fbf
Well-known
I guess there is still no source of the FS adapter...
