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07-24-2010, 04:51 PM   #16
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NIKON: I have some Nikon-mount glass. I'm not at all familiar with all the permutations of the F-mount, but one lens is AF and DEFINITELY doesn't fit. Many of the manual lenses force-fit with no great problem. I've done basic surgery on a couple for better fit -- with a Dremel Moto-Tool and metal-cutting disc, I removed protrusions (like a flag) from the lens base, and thinner protrusions (carefully!) from the bottom of the aperture ring. They lock into a Pentax mount with about 1/8 turn, nice and solid. And they work with Catch-In-Focus, nicely shorting the appropriate pin.

Other F-mounts, third-party, have a lip around the aperture ring, rather than just two protruding sections. I haven't tried cutting away that much; I just force the lens into the Pentax mount, and it seems to lock-on solidly. But as was warned above: these are not rock-solid connections. I take great care not to slam the lenses, not to strain the mounts. Anyway, these old Nikon mounts work fine on my K20D, and I'm looking for more.

CANON: I have some Canon FD lenses that I'd surely love to use on my K20D. None are so unique that they're worth wasting money on an adapter. Dare I try a bit of surgery on them? Maybe I'll miscegenate one with the Nikon-F base from a Vivitar teleconverter. (I don't have any extra PK bases, ratz...) Will that gain me the 3.46mm I need for infinity focus? I'll have to try that the next time I feel brave -- haul out to my machine shop (the Dremel on the back-porch railing) and see what happens. Stay tuned for developments...

ANOTHER APPROACH: In this recent thread at MFLenses.Com a Kiwi converted a Pentax P30t to a Nikon mount. Terrible waste of a P30t, eh? If I only had a Canon TC, I could try something like that with one of my excess M42 SLRs -- oops, they all have metal mounts. What to do, what to do?? Dang, these Canon lenses are like an albatross around my neck.

07-26-2010, 10:19 PM   #17
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Nikon/Canon on a Pentax

Hey RioRico,
I nor any tech know would waste any time trying to carve on or just change a ring on the Canon
ring . The "registration" on the Canon is not close to that of the Pentax like the Nikon is.
You can buy an adapter even on ebay (cheap) with a corrective lens and a safe mount if a Canon lens is what you desire to use on the Pentax..
But remember the Nkon lens that you think s fittng is not really . The Pentax lens (bayonet ) screws on clockwise but the Nikon lens screws on it's body counter-clockwise.
It is a coincidence that the rear end of the threads on the mounts are catching and bending some in order to catch enough to appear to hold. The registration is almost the same so most of the shots will focus OK. Depends on the lens. If you need a Pentax lens mounting ring cheap to mill on to the Nikon you can sometimes buy a cheap undesirable Pentax lens for less than a mount ring would cost. Then take the mounting ring off of the lens and install it on the OLD Nikon lens you want to use.
But as I mentioned in the earlier thread , the ring you install on to the Nikon lens will need a thin spacer between it and the new ring to match the Pentax "registration" distance. This modification gives you a secure and safer attachment for old Nikon lens to Pentax body .

Be careful with the experimental fitting and don't screw up your bayo mount on your Pentax body like others have done.

Last edited by Big Screen; 07-26-2010 at 10:51 PM.
09-11-2010, 03:42 PM   #18
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QuoteOriginally posted by Big Screen Quote
WARNING ! To All you guys that are screwing Nikon lens on Pentax body.

You are gravely mistaken to think the old Nikons "fit" on the Pentax SLR bodies.

It's just barely staying together(not "fitting") with lots of potential damage to your camera or possibly the lens. You see ...the Nikon lens screws on the it's camera in the opposite direction from the way a Pentax lens screws on to a Pentax body.
The parts of the Nikon lens that are holding is the back end of the treads to the THIN tail end of the treads on the Pentax body. If you bump or in some cases snug it a little more to tighten it up, just a little , you can damage or warp the thread fins & bayonet mount on your camera . You will then not be able to get ANY Pentax lenses back on your new Digi Pentax SLR. In some cases the aluminum bayonet threads just break .Continuous use will definitely start to fatigue and crack your bayonet threads the more you try to match the Nikon to the Pentax mount.
Many people have already done it. It makes the repair shops happy . They do need the extra income in this destroyed economy though.

If you feel compelled to attach the Nikon lens to the Pentax buy the adapter off the .NET and deal with the extra glass to compensate for infinity. Or have the bayonet ring on the lens replaced with a Pentax. This will require a tech that knows how to drill the precise holes and thread for new screws. Oh yes, you wll need a very thin spacer between the ring and lens to match the "lens registration" distance. This is coincidentally about the thickness of 35mm film.

Be careful my fellow Pentaxers

So this is to dangerous to do I suppose? How badly do those converters distort IQ? Here are my two main Nikon lenses I use, I didn't know it was possible to do this at all so it does interest me, but only if it keeps the quality.

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Will these 2 work? Do I need to buy an adapter and if so will that really kill the IQ?
09-11-2010, 05:23 PM   #19
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When I tested both I found a significant color bleeding wide open in bright light. Stopped down they were fine. I tested both with 50mm F1.8 lenses which maumbe a bit unfair because they are not the greatest

09-11-2010, 07:06 PM   #20
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Neither lens looks worth enough to be bother spending money on the experiment. You can get a brand new 70-300 with AF for Pentax for not much more than 100, and a perfectly good manual 50/1.7 for under 50. You'll get better results with more functionality and less hassle.
09-11-2010, 07:11 PM   #21
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Actually both of those are considered some of the best made from Nikon from what I been told on various Nikon forums....Especially the 50mm, why do you say they are not worth enough? :-/

I took some incredible shots with these in the past. Idk just wanted to know if it was possible.
09-11-2010, 07:32 PM   #22
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I'll admit to not knowing anything about thiese in particular. i'm just going on the general specs. There will dozens of different 75-300-ish lenses made, and many are considered pretty good, but none of them that only f/5.6 at the long end could possibly be worth as much as $100 given that brand new ones are only barely more. And I'm sure the 50/1.8 was very good- lots of 50/1.8's are. And because there were so many of them, none tend to sell for more than $50. like I said, there there is something unusually special about these I am not aware of, but they look like a basic run-of-the-mill slow consumer telephoto zoom and a basic fast prime - the 70's & 80's equivalent of the "kit zoom". I'm not saying they are *worse* than the equivalents I suggested, just that there is very little chance they are *better*. So why spend money on an adapter that *will* compromise IQ or infinity focus when for very little money, you could get lenses that were just as good if not better, that worked better with the exposure system,. and in the case of the telephoto, were autofocus? That's giving up an awful lot to save only a little.
09-11-2010, 07:38 PM   #23
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I see what you mean, Just thought it might have been possible, I actually love the zoom, I got it for 150, hope I can find something as good, It was really good with clarity and color, it just seemed to get everything right without Post processing which was very satisfying, I never used its autofocus since I am on a D40. I am not into auto so much...I like controlling everything even if its slower sometimes doing that.

Thanks though for the info.

09-11-2010, 08:24 PM   #24
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I've modded a few Nikon-mounts for PK-M usage. I'm not that familiar with the Nikon mount labels / nomenclature, but I guess the ones I've chopped are AI types, with the arc and nub at the bottom of the aperture ring. I cut off those protrusions with a Dremel, so the base of the aperture ring is smooth. Then I get a good (but not locked-on) fit on a PK mount. This probably makes them unusable on an AI-mount camera. I don't care. I have no Nikon bodies.

Some lenses with a full skirt around the base of the aperture ring, not just the arc and nub, I don't bother cutting. I just press-fit those onto the PK mount. Those that have been chopped will (safely) short out the PK mount's electrical connectors and thus allow use of Trap-Focus aka Catch-In-Focus. Those that haven't been chopped, don't; I just must focus carefully.

The longest Nikon-base lenses I've put on my K20D are a 200/3.5 (skirted, un-modded) and an IF 80-200/3.9 (modded). I think those are about the maximum I'd trust on the mount, especially un-modded and press-fit. Remember, these aren't locked-on; I'm quite careful NOT to put any strain on the body-lens interface. Although I must admit that my first effort, a Nikkor 85/2 that cost me US$9, sits there pretty solidly.

Are optical adapters worth the expense? Well, do you have an extra Nikon-AI-base TC? Try modding its base as I mentioned above, just removing the arc and nub from the aperture ring. Then mount that on a Pentax, put your candidate lens on it, and check the IQ. The best optical adapter will probably be in the same IQ neighborhood. Do the extra-special qualities of your candidate lenses make it past the TC intact? If so, then get an optical adapter. Hey, it's only money, eh?
09-11-2010, 08:56 PM   #25
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Eh, it's the same with the Yashica C/Y lenses unfortunately. I've finally gotten myself some pretty nice lenses but 3/4 of them are the C/Y mount which makes them useless for mounting on a K-DSLR which ultimately is what I'd choose to do if I could. Short of re-mounting them and thereby losing the use of them on my Yashica film cameras there's not much that can be done to make them work with the cameras I'd like to buy.

On the other hand they do work well on Canon with an adapter so I'm thinking my first DSLR just might have to be a Canon after all. Eventually I'd get a K-something and more Takumars anyways, but I sure wish they had an adapter that actually worked with those C/Y's that would make them fit on a K-x. Distance is all wrong though according to everything I've read. Sometimes trying to figure out all this lens vs adapter stuff, it makes me wish all lenses were made T-mount or Adapt-all style. It would sure make swapping lenses from one camera to another a whole lot easier...
09-12-2010, 05:25 AM   #26
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QuoteOriginally posted by Marc Sabatella Quote
Neither lens looks worth enough to be bother spending money on the experiment. You can get a brand new 70-300 with AF for Pentax for not much more than 100, and a perfectly good manual 50/1.7 for under 50. You'll get better results with more functionality and less hassle.
I don't disagree but since they were free and a good relative comparison they are what I used to test the converters. I got my mothers full nikon kit a few years back and from time to time see long FD lenses go cheap. The converters, due to the magnification are useless for wide angle but the softness wide open on a 50 mm has some possibilities for portrait. Images sharpen cry nicely when stopped down.
09-16-2010, 09:09 PM   #27
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QuoteOriginally posted by Abstract Quote
So this is to dangerous to do I suppose? How badly do those converters distort IQ? Here are my two main Nikon lenses I use, I didn't know it was possible to do this at all so it does interest me, but only if it keeps the quality.

Attachment 70488

Attachment 70489

Attachment 70490

Attachment 70491

Will these 2 work? Do I need to buy an adapter and if so will that really kill the IQ?
No , I don't think these are really that special of or valuable lens.
You will only want to REPLACE the Nikon mount ring with a Pentax if you have a special
high quality fast lens.
You are not going to have a secure or safe adaption by just grinding off a couple of areas
or knobs.
Again as I stated in my previous post the Nikon & Pentax are opposite thread patterns from each other and used enough by pressing and turning you WILL finally damage your Pentax.
It is only the tip of the back of the fins barley holding that are making these guys think they have adapted the Nikon lens.
Get a Pentax mount and have someone that is experienced, mill the lens (kind of like a shallow routing) and thread for the new screw wholes. Ofcurse it should be a great lens or it's NOT worth it.

Best of all save some money up and watch . You will find a good Pentax lens which will work the best.
09-17-2010, 10:34 PM   #28
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QuoteOriginally posted by Big Screen Quote
No , I don't think these are really that special of or valuable lens.
Quite true.

QuoteQuote:
You are not going to have a secure or safe adaption by just grinding off a couple of areas or knobs.
No connexion is bombproof. If I mount my TeleTak 200 on my K20D and WHACK it, something will give. This is not a shock-resistant internal-lens P&S.

QuoteQuote:
Again as I stated in my previous post the Nikon & Pentax are opposite thread patterns from each other
Bayonets don't have threads. Look closely at the mounts.

QuoteQuote:
and used enough by pressing and turning you WILL finally damage your Pentax.
What is your experience that leads you to this conclusion? Not theory -- experience.

QuoteQuote:
It is only the tip of the back of the fins barley holding that are making these guys think they have adapted the Nikon lens.
I use a modular macro-tube mount to check the connexion. I can insert the bayonet and see exactly how much fin-to-fin contact there is, just as if I were looking from inside the camera. With a PK-native mount, the overlap is 16mm. With my modded Nikon 85/2 AI-mount, it's 12mm. That is NOT an insubstantial grip.
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