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03-18-2010, 09:53 PM   #1
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K mount to m42 screw mount

Hello everyone,

I just purchased the Genuine Pentax K mount to M42 adapter and how some worries about it. I know people have been using it for their digital SLR for quite some time now but I just had some concerns. I have mounted it to the body no problem but when I mount the M42 lens to it. The lens does not sit centered to the body. As in the aperture and focus distance numbers are situated on the side of the body and not facing upwards towards my eyes. Is this right? It has happened to both my Beck 135mm lens and JC Penney 28mm lens.

My other question is that my Fujica 55mm F2.2 lens seems to have an indentation on it. Which seems to fit into the electrical contacts for the body. I didn't have it powered on or anything but I am worried that I might have caused some damage to it. Does the mount have 2 contacts that are slightly out then 1 that sits flush with the mount and then 3 more out and last one gold?

Another question is regarding the AF screw and the locking pin. If I have the screw mount lens on and then switch to AF mode will it cause problems?

and the locking pin that you push to release the newer K mount lens. Should I be pressing it all the way down as I screw on and off the M42 lens?

Thank you for your assistance.

03-18-2010, 10:10 PM   #2
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QuoteOriginally posted by epqwerty Quote
Hello everyone,

I just purchased the Genuine Pentax K mount to M42 adapter and how some worries about it. I know people have been using it for their digital SLR for quite some time now but I just had some concerns. I have mounted it to the body no problem but when I mount the M42 lens to it. The lens does not sit centered to the body. As in the aperture and focus distance numbers are situated on the side of the body and not facing upwards towards my eyes. Is this right? It has happened to both my Beck 135mm lens and JC Penney 28mm lens.
This is quite common. I don't know if it is by design or it just comes out that way.
QuoteQuote:
My other question is that my Fujica 55mm F2.2 lens seems to have an indentation on it. Which seems to fit into the electrical contacts for the body.
A friend gave me a Fujica ST 901, and that lens will not mount on the K10 with the mount adaptor because of some extra bits sticking out the back. I don't force it, and won't use that lens with the K10d.
QuoteQuote:
I didn't have it powered on or anything but I am worried that I might have caused some damage to it. Does the mount have 2 contacts that are slightly out then 1 that sits flush with the mount and then 3 more out and last one gold?

Another question is regarding the AF screw and the locking pin. If I have the screw mount lens on and then switch to AF mode will it cause problems?
No problems at all. Your camera may or may not go into catch-in-focus mode, depending on whether your lens mount is painted (no go) or if it is too narrow to cover the camera's contacts (also no go). To go into CIF mode, the camera is put into AF Single, and will only take a picture when the focus indicator detects focus. For this to happen the contacts have to be shorted out by the lens.
QuoteQuote:

and the locking pin that you push to release the newer K mount lens. Should I be pressing it all the way down as I screw on and off the M42 lens?
No, I don't with mine.
QuoteQuote:

Thank you for your assistance.
You are most welcome. That's what the forum is for - finding out the answers to questions we have from people who have already found at least one of the answers.
03-18-2010, 10:14 PM   #3
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And don't panic the first time you try and take it off... just in case you don't know... you cannot take it off with the lens... it is lens screws off and then remove the adapter.
03-19-2010, 07:56 AM   #4
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I have a third-party adapter. Despite all the warnings, I have never had any trouble with it.

My lenses line up properly, with the aperture and focus indicators on top of the lens, as they should be. Are you sure you have the adapter mounted correctly. It is possible to insert a k-mount lens (or adapter) into a k-mount body, incorrectly, with the lens rotated approx. 120 degrees from where it should be. I know, because I did this with a k-mount adapter for a t-mount 500mm mirror lens. It was very difficult to remove.

The proper way to mount the adapter is to screw it onto the lens first. Then mount the two onto the camera. When removing, the lens unscrews from the adapter, which must then be removed from the camera seperately.

M42 lenses do not have a hole of slot in the lens for the locking pin to fit into, so pressing the lens release button on the camera does nothing. Some people have gone so far as to drill such a hole in their M42 lenses, but, in my experience, that is not necessary. Friction is more than enough to hold things in place. After all, I never heard any reports of lenses falling off of Spotmatics, back in the day.

On my adapter, I have removed the little spring clip that holds the adapter in the camera body. Now, I can remove the lens and adapter together. Since the only M42 lens I commonly use on my K10D is my old 50mm, f/1.4 Super Takumar, I have effectively turned it into a k-mount lens. I usually leave the adapter on the lens, more or less permanently.

The AF drive connection is spring-loaded, so it simply pushes back out of the way when a non-AF lens is mounted. Frankly, I never pay much attention to the AF setting, when using an M42 lens. The camera senses a manual focus lens, or more precisely, doesn't sense an auto-focus lens, so it operates in manual focus mode anyway.

One question you didn't ask, which often comes up with new M42 users, relates to the SR setting. When the camera asks for the focal length, enter the actual focal length. Do not multiply by 1.5. A 50mm lens is still a 50mm lens, even though the field of view on an APS-C camera is equivalent to that of a 75mm lens on a full-frame film camera.

03-19-2010, 08:06 AM   #5
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All of my lenses but one align fine with a solid twist, but it's not even important.

As a matter of fact, I kind of like the left leaning aperture ring on my MIR 37mm. It's funky!
03-19-2010, 08:40 AM   #6
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Currently, all my M42 lenses are Taks and they line up with the adapter. With the Vivitar 2x converter screwed in, it's about a quarter turn off. Thats just the difference in machining on the threads. It's nothing to be concerned about other than the inconvience of different lenses lining up in different places. The same thing happens with some lenses in the M42 camera bodies also.
03-19-2010, 10:08 PM   #7
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I was told by the retailer that the adpater goes on the mount first followed by the lens. Not the lensto the adapter first but I don't think that there is much of a difference. Perhaps only some speed difference other than that not much. Thanks for the help. And yes I am awae that the shake reduction is the distance of the lens un multiplied. But good information for those that might happen to cross this thread looking for infomation on it.
03-20-2010, 10:19 AM   #8
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QuoteOriginally posted by epqwerty Quote
I was told by the retailer that the adpater goes on the mount first followed by the lens. Not the lensto the adapter first but I don't think that there is much of a difference. Perhaps only some speed difference other than that not much. Thanks for the help. And yes I am awae that the shake reduction is the distance of the lens un multiplied. But good information for those that might happen to cross this thread looking for infomation on it.
You bought yours from a retailer, and you say it's the genuine adapter? Who did you buy it from?

And yes--adapter to body, then lens.

03-20-2010, 10:44 AM   #9
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To my knowledge it is the genuine part same part number and the packaging is the same as that as what I've seen. Also the instruction pamplet is hoya Corp and the adapter has pentax on top and japan on the bottom. Which looks like the original one not the ashai pentax one though. I have no reason to mistrust them as I've been shopping from that same camera store for a long time and they have always been honest and trustworthy with me in the past. Ptx 30120
03-20-2010, 10:55 AM   #10
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QuoteOriginally posted by epqwerty Quote
To my knowledge it is the genuine part same part number and the packaging is the same as that as what I've seen. Also the instruction pamplet is hoya Corp and the adapter has pentax on top and japan on the bottom. Which looks like the original one not the ashai pentax one though. I have no reason to mistrust them as I've been shopping from that same camera store for a long time and they have always been honest and trustworthy with me in the past. Ptx 30120
I believe you, but it's just rare to find a store carrying it.
03-20-2010, 07:47 PM   #11
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As a photo specialty retailer I kinda hope it stays that way. I sell a lot of these adapters and customers always make me feel like a hero for finding them this gem. It's pretty amazing how happy a $20 item can make a person feel, but that is one of the cool things about this hobby. How many people solve their golf problems with a $20 item?

BTW it does not make any real difference at all whether you put the adapter on the body first or the lens first, other than if you put it on the lens first you will take the adapter off the body after the lens is removed anyway (unless you remove the spring as mentioned). It also shouldn't make any difference if your focusing scale is rotated away from the top of the lens.
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