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05-26-2009, 09:22 AM   #1
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Is it possible?

hi, does anyone know, is it possible to use Nikon's lenses on pentax bodies?

the sensor size is very similar, the multiplication factor is the same 1.5 so, maybe it is possible?
and nikon have such a lens.. 24-85mm f/2.8-4 i'd love to use for my everyday shooting..

05-26-2009, 11:37 AM   #2
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I think it might be possible, but you would lose autofocus and auto-metering capability. Why not pick up a Tamron 28-75mm f/2.8?

But if you REALLY want to do this, read this - http://forums.dpreview.com/forums/read.asp?forum=1036&message=19738793
05-26-2009, 11:49 AM   #3
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the nikon F registration distance is about 1 mm further than the pentax registration distance, therefore it will (assuming it can be mounted) focus past infinity.

there have been posts in the past about mounting nikon F onto Pentax, but as others have pointed out, at the loss of AF and the aperture coupling
05-26-2009, 06:04 PM   #4
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I read somewhere the lenses almost fit, you turn them on the mount but do not lock. The lens you mentioned is hardly a special lens I have no idea why you'd want to use it. The focal length is adequate for full frame, you lose wide angle on a pentax camera.

05-26-2009, 06:50 PM   #5
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QuoteOriginally posted by Mystic Quote
hi, does anyone know, is it possible to use Nikon's lenses on pentax bodies?

the sensor size is very similar, the multiplication factor is the same 1.5 so, maybe it is possible?
and nikon have such a lens.. 24-85mm f/2.8-4 i'd love to use for my everyday shooting..
It's possible: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/61123-k-mount-...2-8-k-7-a.html
05-27-2009, 09:06 AM   #6
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QuoteOriginally posted by kristoffon Quote
I read somewhere the lenses almost fit, you turn them on the mount but do not lock.
Yup. I accumulated a pile of [gasp!] non-Pentax lenses, including a nice Nikkor 85/2 and some 3rd-party F-mount stuff. Most of the latter duplicates various of my Petax-y lenses, but I've just started using a Tokina 35-135/3.5-4.5 that fills a gap in the lineup. Each cost US$9 so I'd be a fool not to use them on my K20D and ZX-M.

That may be possible but not very stable. The Nikon tab should be at the 6-o'clock position, straight down. The gap between lens and body is much less, and more even, than if the tab points up. I still have to be careful not to focus too far or too hard, else the lens may attain its separate identity (ie, it falls off).
05-27-2009, 09:20 AM   #7
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QuoteOriginally posted by RioRico Quote

Originally Posted by dave9t5

It's possible: K-mount Nikkor AIS 28/2.8 (on a K-7!)


That may be possible but not very stable. The Nikon tab should be at the 6-o'clock position, straight down. The gap between lens and body is much less, and more even, than if the tab points up. I still have to be careful not to focus too far or too hard, else the lens may attain its separate identity (ie, it falls off).
Don't worry, that Nikkor in that photo is fully converted to K-mount.

Augustmoon did it. I don't know all the details but it involved an old lens-mount, some dremel-ing, drilling and shim-ing.

You can see another view here (far-right):

05-27-2009, 09:41 AM   #8
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the best (if that is a good way to describe it) way to modify an old nikon mount to a pentax mount is to purchase a flanged M42 to K mount adaptor, and attach it to the lens, using necessary spacers to correct the register distance.

If you are mechanically inclined, it might be possible to modify th eaperture activation lever to allow automatic stop down in manual focus, otherwise, it will work best in Av mode as a stop down lens (like M42)

05-27-2009, 09:49 AM   #9
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Yep, sure is!!

I have had and used on my K20D the Nikkor 24mm F2.8, and the Nikkor Micro 55 F3.5 And currently use the 28 AIS 2.8 and the 105 AI 2.5!!

I recently about a week ago permanently converted a really terrific Nikkor AIS 28mm F2.8 Close focus lens for K-mount. This is sporting a K-mount (from a Sigma lens) and is fully converted to where it has a real-k-mount and is setup for perfect infinity focus where I reach perfect infinity when turning it to full-stop.

Infinity is about 1.04mm further away, so a shim or gasket or pudding lid (thicker than yogurt lids) works well as a shim, on my "permanent" conversions I use the dremel to add some metal and take out thickness, so it is more "solid"

This lens functions fully in AV mode, it is stop-down system, so you focus if you want more light at f2.8 and then stop down to your shooting aperture, then the camera selects the shutter speed. On bright days, I just leave it on the shooting aperture because there is enough light to focus with, I also have a Katz Eye screen for focusing.

But this lens now fits and mounts as nicely as any of the M's I used to have.

I recently picked up a very sweet Nikkor AI 105 f2.5, that I have converted (but not permanently yet, waiting for a dead k-mount mount to cannibalize) This lens has some of the nikon mount "features" ground off, so that it fits on the K20D smoothly (it twists just a little bit, but I drilled a hole in the Nikkor mount where the Pentax locking pins goes, so it fits on firmly. I also have a plastic lide which I cut down to fit under the mount, so I have perfect infinity focus. Once I get my spare K-mount, then I will readjust the infinity. But as it is now it twists on about 20 and then because I drilled the hole, locks firmly in place.

Attached is an infinity shot at 5.6 and the crop. This 28mm lens is really fantastic as it does it all between a couple inches and infinity. The boat is at 5.6, the flower (tiny geranium bud) is 2.8 the bud is only about .5 inches long, probably smaller. The Sigma mount I used is from an auto lens, so it has a lot of extra gaps and holes that I did not need, and makes it a bit uglier than using a M42 adapter that has a full flange on the bottom or an old K or M mount would also look a lot cleaner.
Attached Images
       

Last edited by augustmoon; 05-27-2009 at 11:47 AM.
05-27-2009, 10:11 AM   #10
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the mount

here is the finished mount, this is a K-mount, so it fits on the same as any other K-mount lens, and I set it up so that the top of the lens points directly to the top of the camera!
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05-27-2009, 11:46 AM   #11
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QuoteOriginally posted by Lowell Goudge Quote
the best (if that is a good way to describe it) way to modify an old nikon mount to a pentax mount is to purchase a flanged M42 to K mount adaptor, and attach it to the lens, using necessary spacers to correct the register distance.

If you are mechanically inclined, it might be possible to modify th eaperture activation lever to allow automatic stop down in manual focus, otherwise, it will work best in Av mode as a stop down lens (like M42)
I was playing around with adapting the auto aperture lever to work within the Pentax mount, and while I was successful, I actually decided that I preferred to use it in AV mode, than in M mode with the green button and all...

If you grind the Nikkor mount down a little around the neck of the mount where the flanges are, the K mount will slip over, but the combined thickness of both the K-mount and the Nikkor mount will be to thick for infinity. If you grind off a little of the bottom of the Kmount as well as grind down the Nikkor mount as well, then you can do so to get perfect infinity (if you have the patience to grind a little, check, grind a little) This might be the easiest way to do so. Some of the Nikkor AI and AIS mounts have the aperture control within the mount itself, making the Nikkor aperture ring a bit useless without the mount also attached. Some of the mounts (like the 105) the aperture ring is capable of opening and closing the aperture by itself, so in this case the old nikkor mount is really not needed and you can swap out the mount directly by drilling new holes in the K-mount (you will have to shim), and better removing the light baffle from the old mount and installing it (or epoxying it) into the Kmount.

The grinding method is a little more involved due to the grinding, but perhaps overall more simple method, that saves time from swapping the light baffle and further reducing the nikkor aperture ring so it doesn't interfere (or grinding down the k-mount to the same diameter as the Nikkor mount) I'm not that mechanically inclined at all, so if I can do this just about anyone can. I have a cheapie dremel-clone and not that good at grinding, so the merging of the two mounts was actually the easiest method for me.
05-27-2009, 11:56 AM   #12
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QuoteOriginally posted by RioRico Quote
Yup. I accumulated a pile of [gasp!] non-Pentax lenses, including a nice Nikkor 85/2 and some 3rd-party F-mount stuff. Most of the latter duplicates various of my Petax-y lenses, but I've just started using a Tokina 35-135/3.5-4.5 that fills a gap in the lineup. Each cost US$9 so I'd be a fool not to use them on my K20D and ZX-M.



That may be possible but not very stable. The Nikon tab should be at the 6-o'clock position, straight down. The gap between lens and body is much less, and more even, than if the tab points up. I still have to be careful not to focus too far or too hard, else the lens may attain its separate identity (ie, it falls off).
Well this one is fully converted so no worries about that. When I first get and test a lens before committing to destructive conversion. I do slightly attach the lens, some fit better than others in this fashion and the nubbins that protrude past the aperture ring rub against the mount (but not badly if you are careful) and also they keep the lens from reaching infinity (too far out)

Also different lenses attach differently. The 55 Micro could mount the best and either mounted at 2 o'clock or 6 o'clock or 10 o'clock. The 24 liked it best at 2 o'clock and the 28 worked best at 10 o'clock and the 105 mounted best at 10 o'clock.

Then when I decide to keep and convert a lens, I will sand off the nubbins with sand paper then it mounts more evenly at different positions, and then a small locking hole where the Pentax mounting pin hits at this configuration, so it won't come off.

you can also reattach the Nikon mount if you want to, to a different rotation then when you put the lens on you can get both best fit and also pointing more correctly upward.
05-27-2009, 01:27 PM   #13
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Original Poster
thanks all for you inputs, and especially to augustmoon, to showing how he had done everything..

but i just concluded, that it's too much of hassles to adapt the Nikkor lenses, i thouhgt maybe there is a simple adaptor, from Nikon mount to K-mount..
but i guess i was wrong..

and yes i'm considering tamron 28-75mm
and I believe it will be my decision..

thanks again for an interesting stuff..
05-27-2009, 01:41 PM   #14
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QuoteOriginally posted by Mystic Quote
thanks all for you inputs, and especially to augustmoon, to showing how he had done everything..

but i just concluded, that it's too much of hassles to adapt the Nikkor lenses, i thouhgt maybe there is a simple adaptor, from Nikon mount to K-mount..
but i guess i was wrong..

and yes i'm considering tamron 28-75mm
and I believe it will be my decision..

thanks again for an interesting stuff..
If you get a good copy of the Tamron 28-75, you will find it can be an excellent zoom lens. It's the only zoom I have, and look at the picky finicky stuck-up crowd it hangs with!
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