K-mount lenses on Fuji GFX

**EstimatedEyes** · 04-30-2020, 03:56 PM

Hey all, just picked up the Fuji GFX-r medium format. There are several adapters available for using K-mount lenses on it and from what I have read in general the vignetting is not bad above 40mm or so. But what I am looking for are real world reports from anyone who has used a K-mount on Fuji G-mount camera ... good bad or indifferent. I hope to use my 43 and 77 limiteds on it (and the 31 as well if I can), but before I buy an adapter I'd love to hear from anyone who has tried any K-mount lenses on a GFX and what their experience has been in terms of ease of use, image quality and any technical problems like vignetting or otherwise. Also, any advice on which adapters are best would be appreciated as well. Thanks.

zapp · 05-01-2020, 02:25 AM

I think it will be on you to tell us. Fotodiox makes an adapter with manual aperture control, quite cheap at $150 - most adapters for less feel like junk anyways. Typically tele lenses cover wider image circles. I would try Macro 50/100 first. I bet that the 77mm will not cover much more than 35mm frame even at f/2.8.

Jonathan Mac · 05-01-2020, 02:50 AM

The last photography item I sold was a K series 35mm f/3.5 lens. When I met up with the prospective buyer I expected him to pull out a FF or APS-C mirrorless camera to try it on and was very surprised when he pulled out a Fujifilm GFX. I mentioned that I was not sure the lens I was selling would provide a sufficient image circle for digital MF and he told me that he got a good deal on the camera body but did not have enough money to buy native Fujifilm lenses for it and was using old Pentax manual lenses. His main one was an M 50mm f/1.7. Though there is some vignetting it's not so much that it can't be handled in post.

MJKoski · 05-01-2020, 03:13 AM

K28mm f/3.5 is able to handle K-1 sensor shift to max limits fine. Just stop down to f/8 and more. When shifted to max limits, K-1 gets very close to GFX sensor area.

My other K-lenses that handle sensor shift well:

Samyang 35/1.4
Zeiss 50mm makro-planar (excellent)
100mm macro WR
Samyang 24mm T/S (well...naturally ;D)

They almost all do but stopping down is needed. Sometimes a lot. Some lenses are a bit messy due to high field curvature and Zeiss 28/2 is perfect example of that. While it handles the shifting, focusing field is so crooked that focus stacking is needed for planar target.

Last edited by MJKoski; 05-01-2020 at 04:29 AM.

surfar · 05-01-2020, 05:09 PM

Originally posted by EstimatedEyes

just picked up the Fuji GFX-r medium format

K&F concept adapters are well made,Ive used them on lots of M/L bodies in the past.

Maybe Mattius will help you with an opinion,but research can be your friend.

MB reviews Ricoh and Pentax gear regularly and is very interesting.Perhaps he may even review some of your lenses?? Could be worth a request??

Youtu.be

**EstimatedEyes** · 05-02-2020, 06:18 PM - **1 Like**

Thanks all. That review of the Laowa 9mm is great (not the least of which because I love my 12mm Zero-D on the K-1). I will be ordering an adapter, and will report back here what I find with my fairly large collection of pentax glass.

**EstimatedEyes** · 05-12-2020, 12:31 PM - **1 Like**

I just completed a series of quick tests mounting a bunch of Pentax FF glass to my new Fuji GFX-50R and thought I would share my preliminary results here. Not posting pictures because they were all handheld high ISO low quality jpg shots just to figure out which lenses might work on the GFX platform. I did not test all apertures, just wide open, a mid-range or two, and stopped down. The good news is all but one appear to be useable at least in some parts of the range. I was surprised that in the shorter focal lengths vignetting was more pronounced wide open than at the smallest apertures. I will try to post more detailed reviews with pics in the forum as I learn more about how these lenses work on the GFX.

Here’s the quick rundown of what I found:

Near full coverage – mild to no vignetting at all apertures: FA 43 Ltd f/1.9; FA 77 Ltd f/1.8; 85 Soft (original version); SMC-M 100 f/4 Macro; SMC-M 200 f/4; Lensbaby Composer,

Very useable – some dark vignetting in corners at extreme apertures, but easily cropped and goes away as you move away from the extremes: FA Ltd 31 f/1.8; SMC-M 50mm f/1.4; SMC-A 50 mm f/1.7; FA 135 2.8

Somewhat useable – dark corners at all apertures but still has significant useable coverage: FA 24 f/2.8, Laowa 12mm Zero-D f/2.8 (with hood removed), FA* 300 f/4.5, Tamron 70-200 f/2.8 (better at longer focal lengths)

Unuseable – Full circle requires crop to near 35mm form factor – FA 20 f/2

A couple notes on adapters. The prior posters probably know this already, but leaving this for the next newbie GFX shooter that comes along

:

You need to enable “shoot without lens” in the GFX menu for them to work. Took me a while to figure out where that was hidden (the Fuji menus are not nearly as logically labeled or laid out as Pentax).

All of the adapters are dumb, in that they don’t transmit any information between the lens and the camera; no AF, aperture control or EXIF info. Through a combination of ignorance, impatience and dumb luck I ended up with three K-mount to G-mount adapters – the AF and Regular adapters from Fotodiox and the adapter from K&F Concepts. Out of the box I preferred the K&F adapter to the others. All fit pretty snugly, but K&F uses the standard lens release button on the Pentax side that we are all familiar with, while Fotodiox uses just a metal pin that you have to press on. The K&F seems to go on a little smoother as well, and is much cheaper than the others. Be forewarned, however, that they are slow to ship and do not respond to most customer inquiries about order status. They did not mark it shipped until after I initiated a refund request, and did not actually ship it until after I opened a paypal dispute. YMMV.

All of my tests but one were using the K&F adapter, though I expect the Fotodiox will perform the same. I tested the Tamron using Fotodiox’s autofocus adapter because it lacks an aperture ring. Despite the name and the hefty price, that adapter does not permit the lens to AF; it just has an extra metal ring that provides 8 stops of aperture control for modern AF lenses that do not have aperture rings. It was shipped to me by mistake after I figured that out and cancelled the order, so it is going back. Being able to test it confirmed that I don’t need it because the glass I want to use all has aperture control rings.

Last edited by EstimatedEyes; 05-12-2020 at 01:39 PM.

MJKoski · 05-13-2020, 01:44 AM

I would not touch FotoDiox adapters even with a big stick. I almost wrecked Sony A7R2 and Canon 24mm TS-E mk2. The tripod foot of FotoDiox Adapter had VERY BAD design to connect it to the adapter body - very small screws and some glue. The foot snapped clean off and the lens-camera combo naturally fell but I managed to catch it before it hit the ground. Your setup is so expensive that I would only use Novoflex with it. German made stuff with proper bolts to attach everything together.

Too bad, Novoflex does not make K-adapter but they have one for Nikon lenses:
https://www.novoflex.de/en/products-637/lens-adapters//adapterfinder-product...jectiv/38.html

**EstimatedEyes** · 05-13-2020, 12:47 PM

Yeah I read about problems with Fotodiox frying a couple Sony cameras. I was less worried about this one since its a dumb adapter, but what you say about the tripod mount does give one pause. And, as I said, the K&F adapter does seem more well put together and will be the one I keep. Novoflex was my first stop, but as you say they have not got around to doing a K>G mount adapter yet.

KiloHotelphoto · 05-19-2020, 11:54 PM

This is interesting, I've read lots of things of people using Pentax 645 lenses on the Fuji but never knew that full frame lenses could be mounted also.

I've been looking at used crop medium format bodies, 645Z and Fuji GFX 50 and you can get some good deals. I don't mind the size of the Pentax and they have a larger selection of lenses but I don't have much confidence in Ricoh sticking with the format. Fuji is putting a lot into their system and it may be smarter to buy into that.

MJKoski · 05-22-2020, 02:03 AM

Canon 24mm TS-E MK2 and 17mm have been adapted to Phase One systems for a decade now. They are not only super wide but also allow large set of movements. It should be possible to mount them to GFX using smart EF->G adapters so that aperture works. They would be my choice for GFX wide angle.

MJKoski · 06-22-2020, 02:03 AM

Wowzer! I found a used 50R for 2599€. Gonna pick it up today or tomorrow. I was hunting for a used 645Z but this has to do for now. Gonna try my K-lenses should I get an adapter some day.

04-30-2020, 03:56 PM	#1
EstimatedEyes Site Supporter Join Date: Apr 2008 Location: NorCal Photos: Gallery \| Albums Posts: 217	K-mount lenses on Fuji GFX Hey all, just picked up the Fuji GFX-r medium format. There are several adapters available for using K-mount lenses on it and from what I have read in general the vignetting is not bad above 40mm or so. But what I am looking for are real world reports from anyone who has used a K-mount on Fuji G-mount camera ... good bad or indifferent. I hope to use my 43 and 77 limiteds on it (and the 31 as well if I can), but before I buy an adapter I'd love to hear from anyone who has tried any K-mount lenses on a GFX and what their experience has been in terms of ease of use, image quality and any technical problems like vignetting or otherwise. Also, any advice on which adapters are best would be appreciated as well. Thanks.

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05-01-2020, 02:25 AM	#2
zapp Pentaxian Join Date: Jul 2011 Posts: 2,385	I think it will be on you to tell us. Fotodiox makes an adapter with manual aperture control, quite cheap at $150 - most adapters for less feel like junk anyways. Typically tele lenses cover wider image circles. I would try Macro 50/100 first. I bet that the 77mm will not cover much more than 35mm frame even at f/2.8.

05-01-2020, 02:50 AM	#3
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,894	The last photography item I sold was a K series 35mm f/3.5 lens. When I met up with the prospective buyer I expected him to pull out a FF or APS-C mirrorless camera to try it on and was very surprised when he pulled out a Fujifilm GFX. I mentioned that I was not sure the lens I was selling would provide a sufficient image circle for digital MF and he told me that he got a good deal on the camera body but did not have enough money to buy native Fujifilm lenses for it and was using old Pentax manual lenses. His main one was an M 50mm f/1.7. Though there is some vignetting it's not so much that it can't be handled in post.

05-01-2020, 03:13 AM	#4
MJKoski Veteran Member Join Date: Aug 2016 Posts: 1,784	K28mm f/3.5 is able to handle K-1 sensor shift to max limits fine. Just stop down to f/8 and more. When shifted to max limits, K-1 gets very close to GFX sensor area. My other K-lenses that handle sensor shift well: Samyang 35/1.4 Zeiss 50mm makro-planar (excellent) 100mm macro WR Samyang 24mm T/S (well...naturally ;D) They almost all do but stopping down is needed. Sometimes a lot. Some lenses are a bit messy due to high field curvature and Zeiss 28/2 is perfect example of that. While it handles the shifting, focusing field is so crooked that focus stacking is needed for planar target. Last edited by MJKoski; 05-01-2020 at 04:29 AM.

05-02-2020, 06:18 PM - 1 Like	#6
EstimatedEyes Site Supporter Join Date: Apr 2008 Location: NorCal Photos: Gallery \| Albums Posts: 217 Original Poster	Thanks all. That review of the Laowa 9mm is great (not the least of which because I love my 12mm Zero-D on the K-1). I will be ordering an adapter, and will report back here what I find with my fairly large collection of pentax glass.

05-12-2020, 12:31 PM - 1 Like	#7
EstimatedEyes Site Supporter Join Date: Apr 2008 Location: NorCal Photos: Gallery \| Albums Posts: 217 Original Poster	I just completed a series of quick tests mounting a bunch of Pentax FF glass to my new Fuji GFX-50R and thought I would share my preliminary results here. Not posting pictures because they were all handheld high ISO low quality jpg shots just to figure out which lenses might work on the GFX platform. I did not test all apertures, just wide open, a mid-range or two, and stopped down. The good news is all but one appear to be useable at least in some parts of the range. I was surprised that in the shorter focal lengths vignetting was more pronounced wide open than at the smallest apertures. I will try to post more detailed reviews with pics in the forum as I learn more about how these lenses work on the GFX. Here’s the quick rundown of what I found: Near full coverage – mild to no vignetting at all apertures: FA 43 Ltd f/1.9; FA 77 Ltd f/1.8; 85 Soft (original version); SMC-M 100 f/4 Macro; SMC-M 200 f/4; Lensbaby Composer, Very useable – some dark vignetting in corners at extreme apertures, but easily cropped and goes away as you move away from the extremes: FA Ltd 31 f/1.8; SMC-M 50mm f/1.4; SMC-A 50 mm f/1.7; FA 135 2.8 Somewhat useable – dark corners at all apertures but still has significant useable coverage: FA 24 f/2.8, Laowa 12mm Zero-D f/2.8 (with hood removed), FA* 300 f/4.5, Tamron 70-200 f/2.8 (better at longer focal lengths) Unuseable – Full circle requires crop to near 35mm form factor – FA 20 f/2 A couple notes on adapters. The prior posters probably know this already, but leaving this for the next newbie GFX shooter that comes along : You need to enable “shoot without lens” in the GFX menu for them to work. Took me a while to figure out where that was hidden (the Fuji menus are not nearly as logically labeled or laid out as Pentax). All of the adapters are dumb, in that they don’t transmit any information between the lens and the camera; no AF, aperture control or EXIF info. Through a combination of ignorance, impatience and dumb luck I ended up with three K-mount to G-mount adapters – the AF and Regular adapters from Fotodiox and the adapter from K&F Concepts. Out of the box I preferred the K&F adapter to the others. All fit pretty snugly, but K&F uses the standard lens release button on the Pentax side that we are all familiar with, while Fotodiox uses just a metal pin that you have to press on. The K&F seems to go on a little smoother as well, and is much cheaper than the others. Be forewarned, however, that they are slow to ship and do not respond to most customer inquiries about order status. They did not mark it shipped until after I initiated a refund request, and did not actually ship it until after I opened a paypal dispute. YMMV. All of my tests but one were using the K&F adapter, though I expect the Fotodiox will perform the same. I tested the Tamron using Fotodiox’s autofocus adapter because it lacks an aperture ring. Despite the name and the hefty price, that adapter does not permit the lens to AF; it just has an extra metal ring that provides 8 stops of aperture control for modern AF lenses that do not have aperture rings. It was shipped to me by mistake after I figured that out and cancelled the order, so it is going back. Being able to test it confirmed that I don’t need it because the glass I want to use all has aperture control rings. Last edited by EstimatedEyes; 05-12-2020 at 01:39 PM.

05-13-2020, 01:44 AM	#8
MJKoski Veteran Member Join Date: Aug 2016 Posts: 1,784	I would not touch FotoDiox adapters even with a big stick. I almost wrecked Sony A7R2 and Canon 24mm TS-E mk2. The tripod foot of FotoDiox Adapter had VERY BAD design to connect it to the adapter body - very small screws and some glue. The foot snapped clean off and the lens-camera combo naturally fell but I managed to catch it before it hit the ground. Your setup is so expensive that I would only use Novoflex with it. German made stuff with proper bolts to attach everything together. Too bad, Novoflex does not make K-adapter but they have one for Nikon lenses: https://www.novoflex.de/en/products-637/lens-adapters//adapterfinder-product...jectiv/38.html

05-13-2020, 12:47 PM	#9
EstimatedEyes Site Supporter Join Date: Apr 2008 Location: NorCal Photos: Gallery \| Albums Posts: 217 Original Poster	Yeah I read about problems with Fotodiox frying a couple Sony cameras. I was less worried about this one since its a dumb adapter, but what you say about the tripod mount does give one pause. And, as I said, the K&F adapter does seem more well put together and will be the one I keep. Novoflex was my first stop, but as you say they have not got around to doing a K>G mount adapter yet.

05-19-2020, 11:54 PM	#10
KiloHotelphoto Pentaxian Join Date: Jan 2015 Location: Glen Mills, PA Photos: Albums Posts: 1,030	This is interesting, I've read lots of things of people using Pentax 645 lenses on the Fuji but never knew that full frame lenses could be mounted also. I've been looking at used crop medium format bodies, 645Z and Fuji GFX 50 and you can get some good deals. I don't mind the size of the Pentax and they have a larger selection of lenses but I don't have much confidence in Ricoh sticking with the format. Fuji is putting a lot into their system and it may be smarter to buy into that.

05-22-2020, 02:03 AM	#11
MJKoski Veteran Member Join Date: Aug 2016 Posts: 1,784	Canon 24mm TS-E MK2 and 17mm have been adapted to Phase One systems for a decade now. They are not only super wide but also allow large set of movements. It should be possible to mount them to GFX using smart EF->G adapters so that aperture works. They would be my choice for GFX wide angle.

06-22-2020, 02:03 AM	#12
MJKoski Veteran Member Join Date: Aug 2016 Posts: 1,784	Wowzer! I found a used 50R for 2599€. Gonna pick it up today or tomorrow. I was hunting for a used 645Z but this has to do for now. Gonna try my K-lenses should I get an adapter some day.