Help! M42 adapter

[richard64]

I bought a Kood M42 to PK adapter. Naively I thought it was compatible with the pentax adapter.

I attached it to a M42 lens and then put it in my K100D. It engaged, as expected - I did not have to force anything, then I turned until I heard a click.

The first thing I noticed was that the body did not ask for focal length - I thought it was supposed to do this. Then in M mode I could not get the body to provide an exposure so I decided to remove the lens.

I unscrewed the lens and then used the Kood tool to try and remove the adapter. It did rotate, but the adapter won't come out. I then heard a ping and the leaf string from the adapter fell out.

Now I have the adapter in the body, I can rotate it 30 degrees or so, but I cannot remove it.

Help! what do I do next?

Richard

[Mike Cash]

Not familiar with the Kood. If it is one of the models that has a flange covering the electrical contacts that would explain not asking for focal length. I use aluminum foil to cover the contacts and the same thing sometimes happens.

I would guess that a small portion of the locking spring remains attached and protrudes just enough to cause it to catch on a bayonet lug. Try using a small pair of tweezers to compress the remaining portion of the spring down to the adapter body and rotate the adapter while still holding the spring remnants clamped down.

Oh, and you might want to do that last bit with the camera held "upside-down" (with the body opening facing the floor) so just in case something else breaks off gravity will work to reduce the chances of it falling into and damaging your mirror or focus screen.

[richard64]

Originally Posted by Mike Cash

Not familiar with the Kood. If it is one of the models that has a flange covering the electrical contacts that would explain not asking for focal length. I use aluminum foil to cover the contacts and the same thing sometimes happens.

The Kood adapter looks like a direct copy of the Asahi adapter - when inserted it is flush with the flange, so the contacts touch the lens body. Since the body is painted the contacts are isolated. Which contacts do you cover with foil?

Originally Posted by Mike Cash

I would guess that a small portion of the locking spring remains attached and protrudes just enough to cause it to catch on a bayonet lug. Try using a small pair of tweezers to compress the remaining portion of the spring down to the adapter body and rotate the adapter while still holding the spring remnants clamped down.

Oh, and you might want to do that last bit with the camera held "upside-down" (with the body opening facing the floor) so just in case something else breaks off gravity will work to reduce the chances of it falling into and damaging your mirror or focus screen.

Yes, you are right. After nervously rotating the adapter for a while I decided to use a bit more force. There was a 'ping' and the leaf spring fell out. Then after a bit more manipulation the adapter suddenly became loose and a small screw fell out.

I think that the spring was not properly screwed in and when I first attached the adapter the spring and screw jammed the adapter in place. Without the spring the adapter can now be attached and detached easily. However, one lens I have has a stiff focus ring and I have to be careful not to detach the adapter as I focus . I'll keep a look out for a genuine Asahi Pentax adapter, perhaps that will work a bit better.

[John Kovarik]

I'm in the middle of a similar situation. Because I was nervous about the stories I have read I first removed the adapter spring (Bower/B&H). When I screw my mint SUP TAK 1.4 into the adapter and then attempt to attach to the bodies (K100D and old Program Plus) it will not rotate to the vertical position. I did not want to force it. I am wondering if I have a faulty adapter, but at the moment I am DTW on 42s until I straighten this out.

Any ideas?

[Mike Cash]

@Richard

Cover all the contacts with foil. Just one big foil-fest across everything. This greatly reduces the EV compensation you need for correct metering.

@John

The lens should stop somewhere around 30 degrees short of the full vertical position. That's normal. You'll come to appreciate it doing that the more you use it.

[John Kovarik]

Mike, I really appreciate that news. I had myself thinking all kinds of horrible thoughts.

Great pix! These lenses are very good...........of course the guy behind the lens helps a little.

Thanks, JK

[Fritz]

Originally Posted by Mike Cash

Cover all the contacts with foil. Just one big foil-fest across everything. This greatly reduces the EV compensation you need for correct metering.

That's a great tip Mike. I just tried that with my Super-Takumar 28mm f3.5, and the initial tests look really good. I'm basically getting the same settings now in Av as I do in M and pushing the AE-L button. The Av setting was needing an adjustment of EV +1.3 to +1.7 to match the M mode before. M with the AE-L button seems to be pretty accurate on my k100d, but Av is nicer to use.

[Mike Cash]

One extra little tip regarding the foil:

I found that as far as applying and removing the foil for those rare times I need to remove the adapter and shoot with a K mount lens it is helpful to have something a little more sturdy than just the foil.

What I did was take a 1mm thick piece of polyethylene foam sheeting (same stuff I use to make flash diffusers) and cut it in a shape to fit over the contacts. Then I wrapped it with foil.

That holds the shape better and makes it much easier to reuse. I just tape it on with cellophane tape, a roll of which is now standard equipment in my camera bag.

[Fritz]

That's a good idea Mike. I was thinking of playing around with some ideas of making a more sturdy holder for the foil. I can see how it could be easily torn off from the contacts.

[John Kovarik]

Mike, what kind of adapter(s) do you use? If they have springs, do you leave them on? Have you heard of the technique of drilling a shallow hole in the lens base to accept the K-mount body pin? Either way, any comments?

Thanks...........

[richard64]

Originally Posted by Mike Cash

@Richard

Cover all the contacts with foil. Just one big foil-fest across everything. This greatly reduces the EV compensation you need for correct metering.

Thanks John, I've gone the route of a foil-fest and now when I switch on the camera with SR on I get the screen asking for focal length, so I guess it is now recognising that it needs more info about the lens.

Since I am testing with an old Pentacon lens I'll try and sand off the paint to see if I can get the same effect without having to use foil.

Richard

[hinman]

Originally Posted by richard64

Thanks John, I've gone the route of a foil-fest and now when I switch on the camera with SR on I get the screen asking for focal length, so I guess it is now recognising that it needs more info about the lens.

Since I am testing with an old Pentacon lens I'll try and sand off the paint to see if I can get the same effect without having to use foil.

Richard

I have a Pentacon 50mm f/1.8 and without the foil, I get focal length confirmation. Here are few related blog posts.

2 custom settings with M42 lens
Setup with Pentax M42 mount lens - Hin's Tech Corner

Bowers m42 adapter from BHPhoto
Pentax M42 adapters - Hin's Tech Corner

Pentacon 50mm f/1.8
Pentax M42 Pentacon 50mm f/1.8 - Hin's Tech Corner

Photosets from pentacon 50mm f/1.8

Indoor tests
Pentagon M42 50mm f/1.8 Test Shots - a photoset on Flickr

Av mode with various Ev compensation
M42 Av mode test - a photoset on Flickr

(lots of wb errors but good in sharpness otherwise)
Kindergarden 1st Day - a photoset on Flickr

On my pentacon m42 lens, I always need to dial in +2 Ev compensation for indoor test shots. Almost all test shots done have about +1.5 to +2.0 Ev compensation. I have not tried using the foil as suggested by Mike to reduce the Ev compensation need. Hope others share the under or overexposure problems with m42 lens.

Thanks,
Hin

[Mike Cash]

Originally Posted by John Kovarik

Mike, what kind of adapter(s) do you use? If they have springs, do you leave them on? Have you heard of the technique of drilling a shallow hole in the lens base to accept the K-mount body pin? Either way, any comments?

Thanks...........

I don't have the camera handy (it's in my truck), but I think the adapter is a "Roxsen" or something that sounds like that. It does have a small spring to secure the adapter to the body. I leave the spring on because I don't want the thing rotating around freely on the camera. I use Takumar lenses pretty much exclusively so the adapter always stays mounted on the camera and I just swap out lenses by screwing them on and off. For me it is like I have a screwmount K100D and it has an option for removing a part and accepting K mount lenses.

I've heard of the thing about drilling the hole, but the Takumars don't go out far enough for that to work. Plus I don't have the dough to dedicate an adapter to each lens. And if one is always swapping M42 lens to M42 lens, screwing and unscrewing them isn't that big a deal. I can normally do the whole 1) grab lens from bag 2) remove base cap 3) remove lens 4) put on lens 5) screw on base cap 6) return previous lens to bag 7) input new focal length info process while waiting for a red light.

[JCSullivan]

I don't have the dough to dedicate an adapter to each lens

With a name like yours you must have all the cash you need. Sorry Mike, couldn't resist.
受容の謝罪

[John Kovarik]

Mike, thanks for taking the time to answer. I have a Roxsen on order - it looks well made.

Good shooting!