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12-22-2006, 08:32 AM   #16
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QuoteOriginally posted by Tom Lusk Quote
eBay: NEW Pentax Screw Mount M42 Lens to PK K Camera Adapter (item 180066341738 end time Dec-23-06 21:00:00 PST)

focusses to infinity with no problem.

I removed the locking pin and leave the adapter attached to the lens, effectively converting the M42 lens to Kmount. It's a lot less hassle having each lens with an adapter than installing/removing the adapter each time you want/need to change lens types.

I think it was Carpents that proposed this on a different forum some while back???
I got my adapter last night. Looks just like the real pentax mount, a few dollars less though. Thinking about orderiing one for each old school lens I purchase and converting them all into kmounts. I'll see if I can find the link that shows how this can be done. Seems like it would save alot of time o changing lenses too.

Here ya go
http://www.rit.edu/~andpph/photoforum/pdf/lens_conv.pdf


Last edited by Flaco; 12-22-2006 at 08:41 AM. Reason: add link for screw mount to Bayonet conversion
01-13-2007, 01:50 PM   #17
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It becomes obvious if you already have the lens, but for someone thinking on buying a screw mount lens, plus an adapter, and converting to a permenant bayonet mount... the conversion only works on lens with wide barrels.
01-13-2007, 05:04 PM   #18
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I know it is stating the obvious but there is still a basic difference between the K mount and the M42 with adapter fitted semi permanantly.This is a known feature by those that have both but remains unclear from above posts.

The K mount lens has the aperture lever protruding from the back which is utilised by the digital bodies to provide metering in AV mode whereas the M42 lenses (with adaptors) only operate in M mode and need the AE-L button to obtain correct metering.

By the way the instructions that come with the Pentax genuine ring clearly state to fit the ring to the lens first then clip the lens to the body. A further trick is to learn to recognise where the red dot or other landmark on the adapter needs to be located vis the base of the lens in order to ensure that the aperture slider and the scales sit on the top of the barrel once clipped to the camera. The screwmount has so many rotations before the adaptor fits tight that I find it disorientating and have been known to fit the lens to the camera upside down. Does this mean that the lens will fail to find infinity or focus past infinity.? Now there is a wet sunday afternoon experiment.
02-14-2007, 09:32 AM   #19
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QuoteOriginally posted by Mr. H Quote
I also bought the Pentax adaptor and it works great!

My related questions are;

1 - Has anyone else found that the M42 lenses won't screw on far enough so that the RED Marker is right on the top? They are just off to the side a bit!

2 - When screwing on my Super - Takumar 28mm f3.5 I hear it scratching on the lower right side of the frame inside and it has left a visible scratch mark. Has anyone else noticed this?

Ed
I've experienced the same thing with my S-M-C Takumar 28mm. I traced it to the auto focus pin on the lensmount of my k100d. It lightly brushes against the outside edge of the bottom of my lens. If you set the AF/MF switch to MF, it moves the pin out of the way. Of course, I noticed this too late

03-04-2007, 07:36 PM   #20
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ditto to wrong adapter

QuoteOriginally posted by Matjazz Quote
I would advise getting a genuine Pentax adapter or at least one that sinks in the body thus retaining full focal range of the lens. I had a chance to try a copy of Pentax adapter and it was hard to mount/unmount while genuine adapter fits like a glove and is suprisingly easy to remove.
Ditto for me. I just made the mistake of getting the one with the flange, and it won't focus on infinity. Why do they even make it? I am ordering a proper one from B&H tomorrow. I'll use the flanged one on my macro lens, which doesn't matter if it doesn't focus to infinity.

But the screw mount 50mm/f1.4 I will want to get infinity. It says Super-Multi-Coated Takumar on the lens, and has f-stops down to 16. What series of lens would that be?
03-04-2007, 08:20 PM   #21
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QuoteOriginally posted by dichro1 Quote
Ditto for me. I just made the mistake of getting the one with the flange, and it won't focus on infinity. Why do they even make it? I am ordering a proper one from B&H tomorrow. I'll use the flanged one on my macro lens, which doesn't matter if it doesn't focus to infinity.

But the screw mount 50mm/f1.4 I will want to get infinity. It says Super-Multi-Coated Takumar on the lens, and has f-stops down to 16. What series of lens would that be?
Ummm...it would be the Super-Multi-Coated Takumar 50/1.4.

And it is a fine lens indeed.
03-04-2007, 08:25 PM   #22
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Not true - they will work in Av Mode

QuoteOriginally posted by Arjay Bee Quote
...
The K mount lens has the aperture lever protruding from the back which is utilised by the digital bodies to provide metering in AV mode whereas the M42 lenses (with adaptors) only operate in M mode and need the AE-L button to obtain correct metering.
M42 lenses meter in Av mode. They will work in M mode, too, but any other mode - P, Tv, Av - will work as aperture priority. You stop the lens down and it will meter for you. (Note that you are in stop-down mode here, there is no open-aperture metering in any mode with M42 lenses.)

(PS - I don't think the DSLRs use the physical lever to meter. It is all a calculation based on the widest aperture of the lens IIRC.)
03-04-2007, 08:27 PM   #23
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QuoteOriginally posted by Tom Lusk Quote
I think it was Carpents that proposed this on a different forum some while back???
Yup, that's me! No locking pins, no problems.

I just got back from Italy, and had along 4 or so M42 lenses, all of them with their own adapters, no problems. One of them was even the relatively large Super-Tak 300/4.

03-04-2007, 09:24 PM   #24
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Yeah, I bought one of the el cheapo adapters from eBay. I didn't realize the infinity focus problem before I bought it (undisclosed by the seller ). I guess the silver lining is that it makes me get closer to my subject!

Now I've gone and spent WAY too much for an authentic Pentax one, but I may well still use the cheapo sometimes, because it allows me to change out m42 and K mount lenses a lot faster than the "real" version. I'll probably just keep it attached to my Super-Takumar 50/1.4, which is an awesome portrait lens on a DSLR. I hardly have use for infinity focus in portraiture anyway.
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