Converting k-mount camera to m42 -- permanently?

[Lucius]

Would it not be possible to obtain the m42 lens mount off a scrap m42 camera and replace the K mount off your Chinon with it ?
If the metal flange on the Chinon is the same thickness ( for infinity focus ) you might only need to redrill the holes if differently positioned.
You've no aperture linkages to worry about , so it might just be a straight swap .

I'd thought of that before, but it might be a challenge to find a donor flange of the same thickness; besides, the k-mount is much wider, so again it might prove difficult to find an m42 ring wide enough. Finally, there's this aperture coupling lever that needs to be depressed: the adapter takes care of it (if not quite perfectly), but if swapping mounts, something else needs to take care of it.

 

[neilt3]

I'd thought of that before, but it might be a challenge to find a donor flange of the same thickness; besides, the k-mount is much wider, so again it might prove difficult to find an m42 ring wide enough. Finally, there's this aperture coupling lever that needs to be depressed: the adapter takes care of it (if not quite perfectly), but if swapping mounts, something else needs to take care of it.

Potentially then an m42 lens to Canon EF adapter could be used as a replacement body flange , after removing the K mount flange .
It's a large diameter so might need reducing.
Some adapters are very thin ( like some m42 to Minolta/Sony A mount ) and could be shimmed for the correct registration distance .
Use the original K mount fastened to the M42 mount as a template for drilling on a bench drill to get the holes in the right place .
The aperture coupling could be permanently glued down in its depressed position , so that wouldn't be an issue .

 

[Lucius]

Potentially then an m42 lens to Canon EF adapter could be used as a replacement body flange , after removing the K mount flange .
It's a large diameter so might need reducing.
Some adapters are very thin ( like some m42 to Minolta/Sony A mount ) and could be shimmed for the correct registration distance .
Use the original K mount fastened to the M42 mount as a template for drilling on a bench drill to get the holes in the right place .
The aperture coupling could be permanently glued down in its depressed position , so that wouldn't be an issue .

Yep, a Canon adapter might just work.

But why would this be a simpler solution than just gluing a k-mount > m42 adapter in?

 

[Jesper]

If adapting the camera fails you might want to consider Fuji ST705, ST801 or ST901.

 

[Lucius]

If adapting the camera fails you might want to consider Fuji ST705, ST801 or ST901.

I have (had) all of these, as well as the ST605, ST701 and AZ1. It's just that I'm on a mission to try different bodies that might have something the more usual options don't. I just want to convert the Chinon, I don't need to.

 

[neilt3]

Yep, a Canon adapter might just work.

But why would this be a simpler solution than just gluing a k-mount > m42 adapter in?

Because your problem seems to be that the lens is wobbling when mounted on the m42 to PK adapter .
I've never noticed an m42 lens wobbling on any m42 to any other mounts adapter that I've used .
So it would cure that problem , and be a fairly simple job .

So a glued in m42 to PK adapter might not cure it , especially with more force applied to the joint with from larger lenses .
Super glue probably wouldn't do the job as it only works on mating faces , but a two part epoxy might that's quite a stiff/thick mix would be able to be forced into the gaps , removing the wiggle room .

 

[Lucius]

Because your problem seems to be that the lens is wobbling when mounted on the m42 to PK adapter .
I've never noticed an m42 lens wobbling on any m42 to any other mounts adapter that I've used .
So it would cure that problem , and be a fairly simple job .

So a glued in m42 to PK adapter might not cure it , especially with more force applied to the joint with from larger lenses .
Super glue probably wouldn't do the job as it only works on mating faces , but a two part epoxy might that's quite a stiff/thick mix would be able to be forced into the gaps , removing the wiggle room .

The wobbling happens not between the lens and the adapter, but between the adapter and the camera mount. The adapter is designed to sit loosely in the mount and is supposed to be tightened by the lens being screwed in, which works with Pentax bodies and lenses, but, it turns out, not so well with third-party ones.

But what might make things easier is taking the mount off the camera, having the adapter glued to it, and then attaching the whole assembly back to the camera, rather than trying to glue the adapter to the mount still on the camera.

 

[dynachrome]

I don't understand how screwing the M42 lens into the adapter makes the adapter sit more tightly in the K mount. What is the mechanism for this? M42 lens mounts are not all exactly the same. This has been the case for a long time. I have Konica FP cameras. These are pre-Autoreflex models from earlier in the 1960s. The widest Konica Hexanon lens made for these F mount cameras was a 35/2.8. I have the original adapter for using M42 lenses but not all M42 lenses (like a 28) will sit flat enough against the adapter to reach correct infinity focus. This is just one example of an M42 incompatibility. There are many more.

 

[Lucius]

I don't understand how screwing the M42 lens into the adapter makes the adapter sit more tightly in the K mount. What is the mechanism for this? M42 lens mounts are not all exactly the same. This has been the case for a long time. I have Konica FP cameras. These are pre-Autoreflex models from earlier in the 1960s. The widest Konica Hexanon lens made for these F mount cameras was a 35/2.8. I have the original adapter for using M42 lenses but not all M42 lenses (like a 28) will sit flat enough against the adapter to reach correct infinity focus. This is just one example of an M42 incompatibility. There are many more.

This isn't a perfect analogy, but the principle is the same: the lens functions as a screw, the adapter as a nut, and the mount as, say, a sheet of metal through which the screw goes. By screwing the lens in, the adapter is supposed to be pressed to the mount from the inside, while the lens's shoulders press against it from the outside; the mount is supposed to be jammed between the two as between a screw and a nut. The difference with those is that the adapter is not fully behind the mount, but almost level, and if the mount is just that little bit thinner, or the lens's shoulders are ever so slightly recessed at the wider diameters (as is the case with some lenses), the lens hits the adapter first (and cannot be screwed in deeper), before they tighten around the mount, hence the wobbling.

 

[neilt3]

The wobbling happens not between the lens and the adapter, but between the adapter and the camera mount. The adapter is designed to sit loosely in the mount and is supposed to be tightened by the lens being screwed in, which works with Pentax bodies and lenses, but, it turns out, not so well with third-party ones.

I see what you mean .

But what might make things easier is taking the mount off the camera, having the adapter glued to it, and then attaching the whole assembly back to the camera, rather than trying to glue the adapter to the mount still on the camera.

Using an two part epoxy putty would likely be the easiest adhesive to use .
The type you can repair pipes and radiators with etc .
You could pack some onto the end/side of the adapter before inserting it , then pack it into the gaps with a tooth pick from the other side , once removed from the camera .
Once it sets , it's going nowhere .

 

[Lucius]

Using an two part epoxy putty would likely be the easiest adhesive to use .
The type you can repair pipes and radiators with etc .
You could pack some onto the end/side of the adapter before inserting it , then pack it into the gaps with a tooth pick from the other side , once removed from the camera .
Once it sets , it's going nowhere .

I'm in awe of epoxy since childhood, when I saw it used by 'professionals' but never had it at home; I guess it shouldn't be too difficult though.

I might still try super-glue first; if it doesn't work, I can always soak it in a solvent, since I'm taking the mount off the camera anyway.

 

[M-88]

K-mount is a special beast -- the adapter has to sit completely inside the mount, to allow for infinity focus. There are flanged ones, and they sit tighter, but with these the lens doesn't focus to infinity.

When in situation identical to yours, I bought a flanged adapter and thinned it down. Took some time with a dremel + manual labor with sandpapers of various grit, but now I have an adapter that sits tightly in its place and allws me to focus to infinity. All for 1.5$.

Another option is to shim the lens mount as Kino suggests. Remove the bayonet (it's easier to work on it that way), shim it from behind, put an adapter inside and put the whole thing back again.

Edit: I'd also say that glue is not an option. You never know when you might want to unglue it.

 

[Paul Howell]

If you have K mount body in mind why not just go ahead and try the superglue, there must slovants on the market that removes superglue.

 

[Lucius]

When in situation identical to yours, I bought a flanged adapter and thinned it down. Took some time with a dremel + manual labor with sandpapers of various grit, but now I have an adapter that sits tightly in its place and allws me to focus to infinity. All for 1.5$.

Do you have a picture? Wouldn't the flange have to be extremely thin, to allow for infinity focus?

Another option is to shim the lens mount as Kino suggests. Remove the bayonet (it's easier to work on it that way), shim it from behind, put an adapter inside and put the whole thing back again.

Not sure this would work, as the shim wouldn't affect the position of the mount, the adapter and the lens relative to each other.

Edit: I'd also say that glue is not an option. You never know when you might want to unglue it.

I'm willing to sacrifice the Chinon, but soaking in solvent should an option if I decide to reverse the mod anyway.

 

[Lucius]

If you have K mount body in mind why not just go ahead and try the superglue, there must slovants on the market that removes superglue.

Yep, that's what I'm inclined to do. Waiting for a cheap adapter to arrive from China (the one I have seems to work fine with my ME Super, so I'd rather keep it intact).

 

[dynachrome]

I have M42 adapters for Konica F, Konica AR, Minolta SR/MC/MD, Canon FL/FD, Mamiya NC, Mamiya ES, Mamiya E, Fuji X (film Fuji X), Pentax K, Yashica/Contax and I'm sure others. I do not get a wobble with any of them.

 

[Lucius]

I have M42 adapters for Konica F, Konica AR, Minolta SR/MC/MD, Canon FL/FD, Mamiya NC, Mamiya ES, Mamiya E, Fuji X (film Fuji X), Pentax K, Yashica/Contax and I'm sure others. I do not get a wobble with any of them.

Lucky you ;-)

But seriously, besides the k-mount adapter, I only have a couple of C/Y adapters and a Mamiya NC, and both systems do have wobble, if fairly negligible; so I guess it really comes to what counts as wobble.
(Also have FD and QBM adapters, and these I'll admit have no wobble whatsoever.)

 

[Bill Burk]

Meanwhile I am having a field day with Pentax ES-II and SMCT lenses.

Just pick up a bulk roll of Double-X and the 1/1000 top speed won’t be an issue.

 

[Lucius]

Meanwhile I am having a field day with Pentax ES-II and SMCT lenses.

Just pick up a bulk roll of Double-X and the 1/1000 top speed won’t be an issue.

I got an ES attached to a lens, but it's rather heavier than I prefer, so still haven't tried it out.

1/1000 is often more than enough, but if one wants to shoot at f1.4 on a bright sunny day, even with ASA 50 film one may need to go faster.

 

[btaylor]

1/1000 is often more than enough, but if one wants to shoot at f1.4 on a bright sunny day, even with ASA 50 film one may need to go faster.

ND filters fix that issue.

 

[Lucius]

ND filters fix that issue.

Or a faster shutter speed can. One filter will be fiddly if using more than one lens, and several would be expensive (and fiddly too, if less so).

 

[Paul Howell]

Which of your K mounts do you think you will use? Sort of off the wall but a Pentax SF1n, not too heavy, has interchangeable view finder screen, I salvaged a split screen from an old Miranda and cut it to fit mine, top shutter speed 1/4000 to 30 seconds, with M42 you can of course use manual or aperture priority exposure, auto bracketing and they are cheap, at least in the U.S. Downside unless you have the AA battery insert uses lithium batteries, no spot or matrix metering.

 

[Lucius]

Which of your K mounts do you think you will use? Sort of off the wall but a Pentax SF1n, not too heavy, has interchangeable view finder screen, I salvaged a split screen from an old Miranda and cut it to fit mine, top shutter speed 1/4000 to 30 seconds, with M42 you can of course use manual or aperture priority exposure, auto bracketing and they are cheap, at least in the U.S. Downside unless you have the AA battery insert uses lithium batteries, no spot or matrix metering.

I was thinking about adapting a Chinon CE4s -- it goes up to 1/2000 and has aperture-priority AE. I'll look into the SF1n, thanks.

 

[250swb]

A wobble may be annoying but it's unlikely to affect image quality or be worth converting a camera to avoid.

 

[Lucius]

A wobble may be annoying but it's unlikely to affect image quality or be worth converting a camera to avoid.

Depends on the amount of wobble. But in this case it also affects the meter, making it useless.