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Pentax K+ Multi-Mount

02-20-2013 · By PF Staff in Influential Photo Gear
Pentax K+ Multi-Mount

Today, I will introduce the piece of “gear” that has been most influential to my photographic journey to date. It cannot be bought commercially as it is a self-modified piece of equipment. I call it the Pentax K+ Multi-Mount, a modification of my Pentax K-x camera mounting ring that now lets me mount lens from Nikon F-mount, Olympus OM-mount, Contax/Yashica C/Y-mount and Konica AR-mount in addition to all my Pentax-K lenses.

How K+ Multi-Mount was made

On the front, you cannot see any difference from the usual mounting ring because my modifications were done on the underside of it. After unscrewing the 5 screws that held the mounting ring to my K-x and flipping it over, I filed away some of the metal that were previously at the brass-yellow areas seen below using a Dremel tool. The reason is because these areas were thicker than other mounts so I had to file them down by a few millimeters, flushing it with the non-protruding areas of the ring. There was not much precision required (or possible), only steady hands to ensure an even surface after filing, sufficiently deep and smooth enough to mount all the lenses. Some trial and error is definitely required by mounting the different lenses directly on it. Once tested to accept all lenses, it was time to screw it back to my Pentax K-x.

Using the K+ Multi-Mount

To enable secure locking, I made a notch in a red plastic sticker and pasted it on the lens mounting area of each adapted lens as shown below.

Each different mount lens required different mounting position, some at 3 o'clock while other may be 7 o'clock, except Nikon which coincidentally is the same position as Pentax. Operation-wise is same as Pentax M42 screw mount lenses; Manual mode, Manual focusing and Green button stop-down metering.

Why did I make the K+ Multi-Mount

Jealously. That was the reason I embarked on this project as I wanted to mount lenses of different mounts/makes like what Canon, Micro Four Thirds, NEX and other MILC owners have been doing so easily with adapters. I was so envious of them that I had to do something to make things work out for myself.

The influence of K+ Multi-Mount?

The journey leading to the creation of my K+ mount played its largest influence in my photographic journey. I learnt 3 things from it.

1. Venturing out of the Pentax circle and experience excellent lenses from other makers like Nikon, Olympus, Contax, Yashica and Konica. My current favorite lens are:

  • Nikon's Nikkor AF-S 28-70mm F3.5-4.5. Sharp zoom lens.
  • Olympus's OM Zuiko MC Auto-Macro 50mm F3.5. For macro shots on a small budget.
  • Yashica ML 50mm F2. Almost pancake size.
  • Konica Hexanon AR 50mm f1.4. Close focus only but very sharp at wide-open.

2. Gained tremendous knowledge on the design of cameras, how film register distance affects focusing zone and its ability to focus to infinity, lens locking method and surprising facts of cameras and their makers. Here are some to share:

  • Nikon's F mount mounting direction is anti-clockwise, different from others.
  • Olympus's DOF (Depth Of Field) preview function designed into every OM lenses.
  • Yashica's lenses ability to mount on Contax SLR and their sharing of technology.
  • Konica's outstanding quality lenses was used by Japan Industry Ministry to judge produced lenses from other manufacturers.

3. Learned to bid on/buy used cameras and lenses cleverly (read: really good and cheap) with limited budget from Ebay and ship them back to my country where such deals were rare.

Lastly, I am happy to share my shots here taken with my adapted lenses!

Taken with Nikon Nikkor AF 28-70mm F3.5-4.5 D on the Pentax K-x.

Taken with Konica Hexanon AR 50mm F1.4 on the Pentax K-r.

Taken with Yashica ML 50mm F2 on the K-r.

And finally, an adapted lens family shot:

You can also see more photos of these lens on my Pentax DSLRs:

Finally, if the comments/interests in my K+ Multi-Mount are highly positive, I will seriously consider fabricating it professionally for more Pentaxians to enjoy this modification too!

-Alston (Gnarelsek)

PF Staff's avatar
About the author: Various writers regularly contribute articles to the Pentax Forums homepage blog. More recent articles are published under each author's forum username. We hope you enjoy our guides and news coverage!

Tags: pentax k-mount, k plus, nikon F mount, contax, konica, do it yourself

More Posts in Influential Photo Gear | More Posts by PF Staff

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njben [Delete] Mar 5th, 2014 5:11PM

This is a good news for Pentax user, I am interest in this.

Spectrum250 [Delete] Mar 1st, 2014 4:51PM

I have some excellent Konica Hexanon lenses that I would love to fit to my K20. Count me in.

Pewter [Delete] Apr 6th, 2013 11:11PM

Gnarelsek, please add me to the list of potential interested buyers. What distant country were you referring to -- if you don't mind me asking?

Sky"e" runner [Delete] Mar 28th, 2013 6:29PM

I was surprised you have done quite similar modification! I have testing with OM S Zuiko Auto-Zoom 100~200mm and Nikkor-H Auto 50mm/f2. OM lens is good to fit Modified K mount and no need to adjust the focus infinitely (but there's 0.5mm differences between K and OM).
Nikkor lens is not quite good fit and need 1mm adapter to get infinity focus but it won't to fit .
It will be good to make small two holes on OM lens mount to lock , And good to put a plate with holes on Nikkor lens.
And some people already done similar modification. I found it on Yahoo! auction (Japan) and BBS in Japan.
I think if Pentax makes this mount with new camera, another camera user will buy Pentax DSLR. It looks like Apple prepares to use Mac OSX and Windows on Macs.

pentaxfriend [Delete] Mar 9th, 2013 11:10AM

Very nice work.

nanok [Delete] Mar 3rd, 2013 5:00AM

classA: the trick is he's only grinding on the underside, the "frontside" mount surface remains factory "perfect", so no danger of changing the alignment of the lens; this is only a danger if the lens doesn't mount "tight enough" to the modified mount (it's loose, has some play), but if it's done so that it will force the "adapted" lens onto the outside surface of the mount, you should be golden.

pretty cool, i heard before this could be possible for a few mounts (there's a guy out there who made a "pentax & many others" adapter for his canon i think, based on a pentax-canon adapter).

Have you tried praktica bayonet lenses on it?

cheers, and well deserved win i'd say (it seems many people were inspired, and that's what matters)

Gnarelsek [Delete] Feb 28th, 2013 7:24PM

Thank you to all who voted for me and the "interested" comments. As promised, I am now investigating how to fabricate it professionally so you do not need to DIY one yourself.

Bccgojuryu [Delete] Feb 27th, 2013 7:23PM

I did this today to my k20 and it's a pretty awesome mod, my only complaints are that the aperture on the Nikon lens is locked to whatever you set it , also the Nikon Ai doesn't seem to rest evenly on the plate, yashica-contax work well and i dont have any olympus to try

SergioFromSF [Delete] Feb 26th, 2013 10:58PM

This is great! I have a "Nikon NIKKOR 28mm f/2.8 AIS" lying around, don't know what to do with it.

Spodeworld [Delete] Feb 26th, 2013 8:41PM

I'd love to be able to share my nikon lenses with my pentax cameras.

Scootatheschool1990 [Delete] Feb 26th, 2013 3:22AM

HECK YES! Fabricate it and I will buy it

conseguir [Delete] Feb 25th, 2013 11:06AM

Wow ! thats cool, I want to have one !!!!!

Luppin [Delete] Feb 25th, 2013 1:39AM


davidsyd [Delete] Feb 24th, 2013 4:19AM

good work. I will be on the waiting list if you ever want to make it happen commercially,

PBandJ [Delete] Feb 23rd, 2013 10:53PM

Ohh, very ingenious! I want one too

shaolen [Delete] Feb 23rd, 2013 10:29PM

Let me know how much you charge!!

jhaji [Delete] Feb 23rd, 2013 12:31PM

Way too cool. Monetize your effort before we see knockoffs on ebay. Do it!

downhill [Delete] Feb 22nd, 2013 1:14AM

That is just off the hook crazy! I'd LOVE to have one.

netrex [Delete] Feb 22nd, 2013 1:10AM

This is pretty awesome. Great work. I'm pretty amazed by the fact that this is actually possible.

Gnarelsek [Delete] Feb 21st, 2013 7:41PM

For those interested in video, I just uploaded one on my modification on Vimeo, just search "Pentax K+ Multi Mount". I will try to clear some doubts here as much as I can.
1. Pentax lenses functions (including AF) are not affected in any way.
2. All camera mounts are different but Pentax K have the larger spacings between metal tabs, thus allowing the other mounts lens to clear them for mounting. Note that this is not vice-versa meaning that a Pentax lens will not fit onto an Olympus OM camera (Tried that). I guess I should have added a section "How K+ Multi-Mount is possible".

rajubhai55 [Delete] Feb 21st, 2013 4:45PM

Me too. I would like to have one. One thing we need to check with Pentax parts dept, are the mounts on all DSLR same?

pickone [Delete] Feb 21st, 2013 4:41PM

Ring on Kx looks the same as the one on my dead sf1, plenty of those dead to get cheap on ebay. easier to experiment on something that doesn't matter.

manishved [Delete] Feb 21st, 2013 1:16PM

Count me in as well....willing to beta test.

troenaas [Delete] Feb 21st, 2013 12:33PM

Count me in the group of interested parties...

bdery [Delete] Feb 21st, 2013 12:02PM

chiane, I'm with you ;) I would need much more information, since I find it hard to believe that nothing more complex than some thinning of a piece of metal is required to use any lens with a K-mount camera.

JohnM [Delete] Feb 21st, 2013 11:53AM

Seriously, this could be a business. Get a quality machinist to work this out with you and you could really have a big impact on people... and even your pocketbook.

chiane [Delete] Feb 21st, 2013 10:56AM

Am I the only one slightly confused and wishing there was more info on this?

Spare Tire [Delete] Feb 21st, 2013 8:12AM

I have some capital. Want to start a company together?

ksuwildkat [Delete] Feb 21st, 2013 6:31AM

This would be perfect with a K-01 since the focus peaking would make manual focus easy.

EcoLDK [Delete] Feb 21st, 2013 4:58AM

I'd need one with minolta and canon adapter :)

LaRee [Delete] Feb 21st, 2013 3:17AM

Oh can I send you one of my cameras and have you work it? This is excellent!

pid [Delete] Feb 21st, 2013 1:41AM

PENTAX itself should adopt this idea! That would blow off Canikony 's brain ;-)

GeroniMoe [Delete] Feb 20th, 2013 11:25PM

Excellent concept and delivery! Count me in the group of interested parties...

WillWeaverRVA [Delete] Feb 20th, 2013 10:57PM

This is really neat! I imagine the other lenses would be limited to MF, but does this affect the AF of Pentax lenses at all?

kadajawi [Delete] Feb 20th, 2013 10:02PM

Very cool. Does it have any drawbacks when mounting Pentax lenses? No AF or anything?

I wonder if these couldn't be produced in a factory, with the mounting points marked down on the ring, and with the necessary precision and maybe some improvements (if possible).

SpartanD63 [Delete] Feb 20th, 2013 9:55PM

I might have to try this...

Laurentiu Cristofor [Delete] Feb 20th, 2013 9:41PM

Very interesting approach.

Class A [Delete] Feb 20th, 2013 8:46PM

How do you avoid creating a small tilt? If the mount plane is not a 100% parallel to the sensor plane then lens performance will suffer in parts of the image. The precision required is measured in micrometers, so I wonder how you manage this aspect.

GabrielFFontes [Delete] Feb 20th, 2013 7:57PM

Truly excelent!

pistolero45 [Delete] Feb 20th, 2013 7:52PM

I'm in as soon as I get my third body I'll send ya my Kr!

ddhlee [Delete] Feb 20th, 2013 7:47PM

Wow, this might be my ticket to finally getting a Sigma 120-300/2.8 on my mount. Good thing I have time before making this decision.

SyncGuy [Delete] Feb 20th, 2013 7:44PM

Naise.... I did consider to make one too but i didn't get around to doing it as i'm too busy shooting and/or PP-ing photos.. ;P

But neertheless, i've kept two spare K mount rings for that and i think i'll get down to modding it too! (don't ask me where i get it from.. LOL!)

Gnarelsek [Delete] Feb 20th, 2013 6:49PM

Thank you all for your comments. As mentioned by wildmo, only Konica cannot focus to infinity while the others can. Tried adapting Minolta but lens mount was too small, fitting totally into K mount and not able to lock. Fujica mount was too big. Haven tried a Canon yet as I am still figuring our the many lens mount variation.

zmohie [Delete] Feb 20th, 2013 6:21PM

me too want one

MJL [Delete] Feb 20th, 2013 6:21PM

I want one! Count me in.

willdmo [Delete] Feb 20th, 2013 6:17PM

well done
@vass Look for Flange focal distance tables. if the flange focal distance is the same in mm or a bigger number Infinity is no problem. If its smaller, you need lens hacking.

logically Olympus OM, Contax/Yashica and Nikon will hit Infinity, Olympus and Nikon even can focus behind infinity.

Minolta and Konica work only for close focus work, as Exacta would do

curlednoodles [Delete] Feb 20th, 2013 6:13PM

wow fantastic ingenuity! Pentax, take notes.

pixelsaurus [Delete] Feb 20th, 2013 6:07PM

Best mod I have seen for a while. Finally I might be able to get my wife's Tamron 200-400 f/5.6 to fit on a real camera instead of her Nikon D200.

kkey1 [Delete] Feb 20th, 2013 6:03PM

I want one!!!!

dubcityman [Delete] Feb 20th, 2013 6:02PM

Need to adspp my Minolta Lens to my K20D & K30,NEED INFO.

vass [Delete] Feb 20th, 2013 5:50PM

Great easy tip. My little doubt is, do you focus infinitely with the adapted lenses? Thanks very much for sharing your knowledge.

neuropol [Delete] Feb 20th, 2013 5:38PM

Nicely done. Do you get infinity focus with each of the lenses mounted?