NikonGear'23
Gear Talk => Lens Talk => Topic started by: Michael Erlewine on September 11, 2015, 14:15:36
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The thinnest extension I have is the K-1 ring (5.8 mm). Is there anything thinner? Or, what are the physical constraints? I would like to find a thinner (or have one made) ring to use with WA lenses. Any ideas?
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The K1 ring is the thinnest extension ring that I know of. It's probably close to the thinnest extension that is physically possible with the Nikon mount - after all, the bayonet mount on the lens must be either fully connected to the camera (zero extension) or fully outside (probably 5mm extension at least). Anything shorter would be partially inserted into the camera mount but unable to lock in place.
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The K-1 is about the thinnest you can have and still make it an extension ring, i.e. with bayonets on either side. The K-1 on a 20/3.5 will produce around 1:3 which is about as far into the subject you would like to go.
Anything thinner means you have to take off the mount of your designated WA and either shim it or remove the near-focus stop, or both. Most of the wide angles focus on their own to something like 1:5 to 1:8 (for modern lenses, older designs went normally only to 1:10). The new 20/1.8 Nikkor does a little better to about 1:4.
Somewhere between 1:2 and 1:4 should be within reach by the shimming technique, but to what purpose? Most likely one would increase lens aberrations, introduce spherical and chromatic aberrations, and reduce image contrast.
Also take into consideration that working distance (front of lens to subject) will be very short, or even negative meaning focus gets inside the lens assembly. The latter occurs if you combine 20/1.8 + K-1, by the way.
There was recently some publicity about a generic 15 mm lens from China, cannot recall the maker's name, but the lens allegedly went to 1:1 life-size; however, at this magnification, working distance was reduced to a few mm.
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Bjørn Rørslett: Can I mount the K1-Ring on an autofocus lens? I am confused about that. It does not seem to want to go and I don't like to force it. I hear you on the lack of need, but I always try to try everything. How does one use a relay lens and can you give me an example of a combination or where I can read about this, please?
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How about shimming the bayonet on the lens itself?
Tedious of course...
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K1 fits all af lenses,,, removing the filter on 16mm full frame fish eye gives a little closer focus.
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How about shimming the bayonet on the lens itself?
Tedious of course...
How does one shim a lens?
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K1 fits all af lenses,,, removing the filter on 16mm full frame fish eye gives a little closer focus.
Appreciated!
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How does one shim a lens?
many lenses already have shims to adjust infinity focus so you just add more shims. Others have just an locking of the helicoil and you miss use that to add extension. Both makes you loose infity...
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Shimming might be indeed the best solution, as focusing range for such lenses is very small.
Removing the lens mount and adding (a) shim(s) shoudl be done by an experienced person
such as our Eric Lund here ;-)
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if you can live with 1mm "shimming", and want no aligning problems, just take a Leitax mount for Leica/Nikon, it is 1mm thicker than the std Nikon mount
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if you can live with 1mm "shimming", and want no aligning problems, just take a Leitax mount for Leica/Nikon, it is 1mm thicker than the std Nikon mount
I am not trying to adapt Leica or other lenses. How does one shim a standard lens? I have never done that?
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I am not trying to adapt Leica or other lenses. How does one shim a standard lens? I have never done that?
Leitax mounts are Nikon F mounts for Leica R lenses, but if you use it for a Nikon lens you automatically add 1mm extension. Very simple way of shimming
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Never shimmed a lens before (but did change mounts) but I assume it involves removing the lens mount and sandwiching a thin layer of material when re-mounting the mount, this way the lens is a little further away from the sensor plane than intended hence mimicking a very thin extension ring.
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Never shimmed a lens before (but did change mounts) but I assume it involves removing the lens mount and sandwiching a thin layer of material when re-mounting the mount, this way the lens is a little further away from the sensor plane than intended hence mimicking a very thin extension ring.
Longer screws may be required.
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Longer screws *are* required. Unless the shim(s) itself is mounted to different screw holes than those of the bayonet.
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Longer screws *are* required. Unless the shim(s) itself is mounted to different screw holes than those of the bayonet.
If anyone has an example, I would love to see a photo of how to add a "little" shim, and the steps involved, please.
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I would respectfully suggest buying a Sony A7 series body and using one of the macro focusing Nikon F to Sony E mount adapters available. They will work with any lens with a non-electronic diaphragm (but hard to set aperture accurately with the sliding collar). Still it works, and gives continuous focus.
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I would respectfully suggest buying a Sony A7 series body and using one of the macro focusing Nikon F to Sony E mount adapters available. They will work with any lens with a non-electronic diaphragm (but hard to set aperture accurately with the sliding collar). Still it works, and gives continuous focus.
Been there, done that...many times.. with the A7s, the A7r, A7R2, and A7R3. No thanks! LOL.
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I would note that with the K-1 ring, although you can mount it to an AF lens, the AF contacts will be pressing against the body of the ring, and most Nikon instructions will tell you you should not do that, though they're not specific why. They just state that the K-1 ring is incompatible with AF cameras. It is possible to take a Dremel tool or the like, and grind away a little of the inside of the ring to give clearance, and it then appears to be entirely safe to mount an AF lens.
Thinking out loud here, what would happen if you were to take the mounting ring flange off a dead camera, and the corresponding flange from a dead lens, and screw them together? That would be a little thinner than a K-1.
e.t.a. here is a quick and dirty modification of a K-1. I'm sure one of the proper machinists here could do it much more nicely, as this was done simply with a dremel tool freehand. As you can see I slipped a little and ground off a bit of the mounting bayonet, and you can notice also that the ring is so thin in one spot that it went through to the other side. But it's not compromised in use, and it clears all AF lens contacts handily.
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... Thinking out loud here, what would happen if you were to take the mounting ring flange off a dead camera, and the corresponding flange from a dead lens, and screw them together? That would be a little thinner than a K-1.
Not thinner by much. Plus there has to be room for the release mechanism -- otherwise the contraption would be stuck dead on the lens ....
The K1 builds 5.8mm if memory serves. Perhaps one can trim this to a fraction of a mm less, but not more.
Adding a solid shim to inside of the camera's mount would allow for a much thinner "extension", however the camera then cannot function with the normal focusing range intact.
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K1 is the shortest possible way.
I cut one apart an measured it, it can’t be shorter. The 3 flange wings has to have something to grab onto.
It should be in the thread from our NG trip to south Germany,,,
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Deleted my redundant post.
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K1 is the shortest possible way. ....
For an F mount lens.
Michael also mentioned a Leica lens in there somewhere too.
If the Lieca is an older M39 mount, then that needs a simple adapter M42/M39 -> Fmount.
There are some issues you need to be aware of with the cheapie M39->F adapters too.
The extension on the simple adapters is about 1mm. Obviously you don't get infinity focus with M39/M42 lenses on the F mount, but I'm sure that's what Michael is looking for anyhow.
Is the Leica lens a Leica M-mount or M39 type.
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I would note that with the K-1 ring, although you can mount it to an AF lens, the AF contacts will be pressing against the body of the ring, and most Nikon instructions will tell you you should not do that, though they're not specific why. They just state that the K-1 ring is incompatible with AF cameras.
They just state that the K-1 ring is incompatible with AF lenses. That is why K1 is not mention in the manual of the camera, only K2 is mention in the manual of the camera. K1 is mention as not compatible with AF-lenses, and that is in the manual of the lenses. And it is stated why: Do not attach the following accessories directly to the lens: PK-1 or PK-
11 auto extension rings, BR-4 or BR-2 auto rings, or K1 or K2 rings (the
PK-11A and BR-2A can be used in place of the PK-11 and BR-2, respec-
tively). Failure to observe this precaution will result in damage to the
CPU contacts or other parts of the lens.
(copyed from the manual of AF Micro-Nikkor 60 mm f/2.8D) (They are very inacurate about BR2 and K2 by the way. Those are no way to attach directly to that particular lens)
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i have an even thinner one. not really an extension ring but used for something else. it's just here somewhere i just don't have the time to look for it in a small heap of spare parts :o :o :o
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I see I mis-remembered which K ring is forbidden in the camera manuals, and am probably mis-remembering whether this has come up before.
There is no explanation of the K-2 issue. It looks as if the K-2 clears AI tabs, and clears the CPU contacts in the camera. It's not listed as forbidden for the F4, which suggests it's safe for CPU contacts. I've tried it on a couple of cameras with no apparent issues. Is there some incompatibility I've missed? I turned down the skirt of a K-2 just to be doubly sure it would never hit an AI follower, but it seems to leave plenty of room. Am I missing something here?
edit to add: there does seem to be an issue with the K2, that it locks on in only two of its three possible positions. It seems the pin hole does not line up, and I'm not entirely sure why, but it does not seem to do any harm. This seems to be true on all AI-compatible cameras, including the F3 and F4 for which the K2 is not listed as incompatible, so that factor alone does not seem to disqualify it.
Another edit to add: a little experimentation reveals that the hole misalignment is tiny. I enlarged the hole a very little bit just with the point of a pen knife, and it clicked in. If pin alignment is the only barrier to using a K-2 on recent cameras, enlarging the hole by about a millimeter or less fixes it. It's the hole counter-clockwise from the K2 designation, as you face the flange, and you need to expand it slightly clockwise, or towards the K2, towards the outer diameter. It's so close already that it might click in if you just bevel it a little.
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For an F mount lens.
Michael also mentioned a Leica lens in there somewhere too.
If the Lieca is an older M39 mount, then that needs a simple adapter M42/M39 -> Fmount.
There are some issues you need to be aware of with the cheapie M39->F adapters too.
The extension on the simple adapters is about 1mm. Obviously you don't get infinity focus with M39/M42 lenses on the F mount, but I'm sure that's what Michael is looking for anyhow.
Is the Leica lens a Leica M-mount or M39 type.
Well the question is F-mount to F-mount extension,,, ;) To be able to add just a bit more extension with short focus length F-mount lenses.
Michael was recommended that it is possible to change the F-mount on lenses. There are substitute mounts available. Therefore we briefly talked about Leica R lenses, since that could be slightly relevant to use a conversion F-mount as a substitute mount,,,
Leica M lenses and Leica thread mount lenses are not really relevant here, unless you flip up the mirror and seat the lens inside the mirror box,,, :o ;D
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I see I mis-remembered which K ring is forbidden in the camera manuals, and am probably mis-remembering whether this has come up before.
There is no explanation of the K-2 issue. It looks as if the K-2 clears AI tabs, and clears the CPU contacts in the camera. It's not listed as forbidden for the F4, which suggests it's safe for CPU contacts. I've tried it on a couple of cameras with no apparent issues. Is there some incompatibility I've missed? I turned down the skirt of a K-2 just to be doubly sure it would never hit an AI follower, but it seems to leave plenty of room. Am I missing something here?
edit to add: there does seem to be an issue with the K2, that it locks on in only two of its three possible positions. It seems the pin hole does not line up, and I'm not entirely sure why, but it does not seem to do any harm. This seems to be true on all AI-compatible cameras, including the F3 and F4 for which the K2 is not listed as incompatible, so that factor alone does not seem to disqualify it.
Another edit to add: a little experimentation reveals that the hole misalignment is tiny. I enlarged the hole a very little bit just with the point of a pen knife, and it clicked in. If pin alignment is the only barrier to using a K-2 on recent cameras, enlarging the hole by about a millimeter or less fixes it. It's the hole counter-clockwise from the K2 designation, as you face the flange, and you need to expand it slightly clockwise, or towards the K2, towards the outer diameter. It's so close already that it might click in if you just bevel it a little.
Hmmm, not really impressed by the 'advice'
As a general note; Please make sure you have your facts right when recommending or commenting on such things as warnings regarding mismatching or matching parts, it's almost impossible if one has to read through several posts to get to an answer.
Please check your facts before posting if your in doubt. Thanks - Of course your allowed to think that we are wrong,,,
Maybe reread this thread where Bjørn and Roland among others lens gurus try to tell you their seasoned Hands-on knowledge of the K-Ring Set from Nikon.
http://nikongear.net/revival/index.php?topic=5211.0
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edit to add: there does seem to be an issue with the K2, that it locks on in only two of its three possible positions. It seems the pin hole does not line up, and I'm not entirely sure why, but it does not seem to do any harm. This seems to be true on all AI-compatible cameras, including the F3 and F4 for which the K2 is not listed as incompatible, so that factor alone does not seem to disqualify it.
I don't have F3 or F4. But my K2 mounts and locks in every three posistion on FE and FA but not on any of my autofocus cameras. Same applies to BR2