Is FD lens on K-01 (without glass adapter) and focus to infinite possible?

dmb video · 01-21-2013, 05:59 PM

Hi, I was wondering if the glass is needed on the FD adapters with the K-01 and would it still achieve infinite focus. I have been goggling for days without luck and I have not seen any glassles adapters for FD except for the Sony nex. Has anyone modified an adapter with success?
Thanks in advance and sorry if this has been discussed, I did do forum searches but couldn't find anything helpful.

Adam · 01-21-2013, 06:01 PM

Originally posted by dmb video

Hi, I was wondering if the glass is needed on the FD adapters with the K-01 and would it still achieve infinite focus. I have been goggling for days without luck and I have not seen any glassles adapters for FD except for the Sony nex. Has anyone modified an adapter with success?
Thanks in advance and sorry if this has been discussed, I did do forum searches but couldn't find anything helpful.

Nikon lenses will focus to infinity, but you'll get crappy IQ because of the 1.4x teleconverter that's built-in to the adapters that are out there.

dmb video · 01-21-2013, 06:07 PM

Thanks for your reply Adam. Its the canon fd lenses I want to convert but without the optical glass correction if possible, I assume it has to be possible with the mirror-less K-01 as sony nex users are able to. I have adapters as is for fd to eos - but I don't like the results when I shoot wide open and I am convinced its the adapters messing up the image.

Na Horuk · 01-21-2013, 06:22 PM

The adaption depends a lot on the flange distance and size of mount. Simply not having a mirror does not guarantee you can adapt anything you want. Well, unless you really go to work and make a frankenstein camera.
Usually we get Canon shooters that want Pentax lenses, but you might want to search the forums if anyone has already tried what you are attempting to do.

Swift1 · 01-21-2013, 06:24 PM

Originally posted by Adam

Nikon lenses will focus to infinity, but you'll get crappy IQ because of the 1.4x teleconverter that's built-in.

What?

dmb video · 01-21-2013, 06:29 PM

Originally posted by Na Horuk

Usually we get Canon shooters that want Pentax lenses,.

Ha - guilty

I own three canon dslrs and a ton of pentax glass - both m42 and K-mount - which is why buying the k-01 was an easy decision at the recent price drop. I have a couple of really nice FD lenses that I think would be amazing on the Pentax - there has to be something -
On another note, I have some enlarger lenses (M39) arriving soon - I think I will need a bellows to make them work on the k-01 - that will be another thread Im sure :
thanks for your reply

Swift1 · 01-21-2013, 06:32 PM - **1 Like**

FD lenses are not adaptable to K-mount without the use of glass elements or without losing infinity focus.
The K-01 uses the old K-mount and retains the flange distance which is longer than the flange distance of the FD mount.
I believe that Pentax and Nikon use nearly the same flange distance which is one of the longest of all the major 35mm SLR mounts.
I've read that the K mount and F mount are so similar that you can mount F mount lenses directly to the K mount ( I haven't tried and I'd do more research before trying)

**boriscleto** · 01-21-2013, 06:40 PM - **1 Like**

FD lenses will not focus to infinity on a Pentax with a glassless adapter. A 50mm lens without the glass will focus to a few inches. Telephoto lenses might focus to a few yards. Pre-AI Nikon lenses can be force fit and will focus to infinity. AI lenses need some modification. Nikon auto focus lenses will not fit without and adapter. RioRico was our resident mad scientist when it came to adapting lenses. Sadly he has not been able to post since last spring.

The Canon FD adapter is a 1.42x tele extender, the Nikon adapter is about 1.25x. With the Canon adapter you lose 1.5 stops of light, with the Nikon adapter 1 stop.

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html

Pentax has a flange focal distance of 45.46mm. The only major mounts with a flange focal distance longer than the K-mount are Nikon F, Olympus OM, and Leica R. Contax C/Y has the same flange distance and can be made to fit with some modification.

Canon FD has a flange distance of 42mm. M4/3 has a flange distance of 19.25mm, Sony E-mount is 18mm, that is why there are adapters for every SLR lens mount available for those mounts.

dmb video · 01-21-2013, 06:49 PM

Thanks for the info. I appreciate it.

cyclone3d · 01-24-2013, 03:54 PM

Actually, IF you can adjust the helicoid for infinity focus, you should be able to adapt it to K-mount no problem.

It is going to be lens specific though AND you would need to physically replace the mount to be able to even possibly get infinity focus as the FD register distance is 3.46mm shorter than the Pentax register distance.

I have done this with a Konica 58mm 1.4 lens and was able to get infinity focus on my K10d. With the K-01 it would have been easier becaue I would not have had to file away at the ring that hold in the rear piece of glass in order to clear the mirror.

It is not possible with an adapter, but with physically modifying the lens, it may be possible.

BTW, flanged M42 to K mount adapters work great as replacement mounts for converting lenses.

After looking at the register distance chart again, it really looks to me like FD lenses should be easier to convert than Konica lenses. The Konica lenses have an almost 5mm register distance difference compared to the "only" 3.46mm register distance difference of the FD lenses.

http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

**Lowell Goudge** · 01-24-2013, 04:03 PM

There is a thread that discusses all adaptors that can be used to mount various things to Pentax K mount bodies

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html

Just for info, I have a Nikon to PK and Canon FD to PK adaptors, the Nikon adaptor has a 1.25 magnification and the canon has a 1.45 magnification to sort out infinity focus. Wide open on cheap lenses these adaptors produce a lot of softness and bleeding of colors at edges, but stopped down they are not too bad. The bigger issue is the internal infinity focus elements add focal length, so they are really only suitable for tele lenses

**boriscleto** · 01-24-2013, 04:38 PM

Originally posted by Lowell Goudge

There is a thread that discusses all adaptors that can be used to mount various things to Pentax K mount bodies

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html

Just for info, I have a Nikon to PK and Canon FD to PK adaptors, the Nikon adaptor has a 1.25 magnification and the canon has a 1.45 magnification to sort out infinity focus. Wide open on cheap lenses these adaptors produce a lot of softness and bleeding of colors at edges, but stopped down they are not too bad. The bigger issue is the internal infinity focus elements add focal length, so they are really only suitable for tele lenses

I think I said all that

https://www.pentaxforums.com/forums/pentax-k-01/212701-fd-lens-k-01-without-g...ml#post2249438

dmb video · 01-24-2013, 06:37 PM

Originally posted by cyclone3d

Actually, IF you can adjust the helicoid for infinity focus, you should be able to adapt it to K-mount no problem.

It is going to be lens specific though AND you would need to physically replace the mount to be able to even possibly get infinity focus as the FD register distance is 3.46mm shorter than the Pentax register distance.

I have done this with a Konica 58mm 1.4 lens and was able to get infinity focus on my K10d. With the K-01 it would have been easier becaue I would not have had to file away at the ring that hold in the rear piece of glass in order to clear the mirror.

It is not possible with an adapter, but with physically modifying the lens, it may be possible.

BTW, flanged M42 to K mount adapters work great as replacement mounts for converting lenses.

After looking at the register distance chart again, it really looks to me like FD lenses should be easier to convert than Konica lenses. The Konica lenses have an almost 5mm register distance difference compared to the "only" 3.46mm register distance difference of the FD lenses.

Camera Mounts Sorted by Register

Interesting - thank you. I have an 50mm/ 1.8 I dont care for or need that I could test with first.

dmb video · 01-24-2013, 06:39 PM

Thank you as well boriscleto and lowell

digital029art · 01-24-2013, 07:35 PM

The longer tele FD lenses like the 400/4.5 can be (relatively) easily converted to a K mount flange once you take off the FD mount & associated parts. It's amazing how much space (thickness) the FD mount takes up! Really complicated linkage the FD is .. so the hardest part is linking up the aperture ring back to work the iris.

Kudos to Canon for switching to EOS years ago & for making excellent manual telephotos available for cheap!

01-21-2013, 05:59 PM	#1
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19	Is FD lens on K-01 (without glass adapter) and focus to infinite possible? Hi, I was wondering if the glass is needed on the FD adapters with the K-01 and would it still achieve infinite focus. I have been goggling for days without luck and I have not seen any glassles adapters for FD except for the Sony nex. Has anyone modified an adapter with success? Thanks in advance and sorry if this has been discussed, I did do forum searches but couldn't find anything helpful.

01-21-2013, 06:01 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Originally posted by dmb video Hi, I was wondering if the glass is needed on the FD adapters with the K-01 and would it still achieve infinite focus. I have been goggling for days without luck and I have not seen any glassles adapters for FD except for the Sony nex. Has anyone modified an adapter with success? Thanks in advance and sorry if this has been discussed, I did do forum searches but couldn't find anything helpful. Nikon lenses will focus to infinity, but you'll get crappy IQ because of the 1.4x teleconverter that's built-in to the adapters that are out there. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-21-2013, 06:40 PM - 1 Like	#8
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,476	FD lenses will not focus to infinity on a Pentax with a glassless adapter. A 50mm lens without the glass will focus to a few inches. Telephoto lenses might focus to a few yards. Pre-AI Nikon lenses can be force fit and will focus to infinity. AI lenses need some modification. Nikon auto focus lenses will not fit without and adapter. RioRico was our resident mad scientist when it came to adapting lenses. Sadly he has not been able to post since last spring. The Canon FD adapter is a 1.42x tele extender, the Nikon adapter is about 1.25x. With the Canon adapter you lose 1.5 stops of light, with the Nikon adapter 1 stop. https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html Pentax has a flange focal distance of 45.46mm. The only major mounts with a flange focal distance longer than the K-mount are Nikon F, Olympus OM, and Leica R. Contax C/Y has the same flange distance and can be made to fit with some modification. Canon FD has a flange distance of 42mm. M4/3 has a flange distance of 19.25mm, Sony E-mount is 18mm, that is why there are adapters for every SLR lens mount available for those mounts. Last edited by boriscleto; 01-21-2013 at 06:49 PM.

01-24-2013, 03:54 PM	#10
cyclone3d Veteran Member Join Date: Nov 2010 Location: Huntsville, Alabama Posts: 511	Actually, IF you can adjust the helicoid for infinity focus, you should be able to adapt it to K-mount no problem. It is going to be lens specific though AND you would need to physically replace the mount to be able to even possibly get infinity focus as the FD register distance is 3.46mm shorter than the Pentax register distance. I have done this with a Konica 58mm 1.4 lens and was able to get infinity focus on my K10d. With the K-01 it would have been easier becaue I would not have had to file away at the ring that hold in the rear piece of glass in order to clear the mirror. It is not possible with an adapter, but with physically modifying the lens, it may be possible. BTW, flanged M42 to K mount adapters work great as replacement mounts for converting lenses. After looking at the register distance chart again, it really looks to me like FD lenses should be easier to convert than Konica lenses. The Konica lenses have an almost 5mm register distance difference compared to the "only" 3.46mm register distance difference of the FD lenses. http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html Last edited by cyclone3d; 01-24-2013 at 03:59 PM. Reason: add info

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01-21-2013, 06:07 PM	#3
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19 Original Poster	Thanks for your reply Adam. Its the canon fd lenses I want to convert but without the optical glass correction if possible, I assume it has to be possible with the mirror-less K-01 as sony nex users are able to. I have adapters as is for fd to eos - but I don't like the results when I shoot wide open and I am convinced its the adapters messing up the image.

01-21-2013, 06:22 PM	#4
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	The adaption depends a lot on the flange distance and size of mount. Simply not having a mirror does not guarantee you can adapt anything you want. Well, unless you really go to work and make a frankenstein camera. Usually we get Canon shooters that want Pentax lenses, but you might want to search the forums if anyone has already tried what you are attempting to do.

01-21-2013, 06:24 PM	#5
Swift1 Veteran Member Join Date: Sep 2009 Location: Oregon Photos: Gallery \| Albums Posts: 5,079	Originally posted by Adam Nikon lenses will focus to infinity, but you'll get crappy IQ because of the 1.4x teleconverter that's built-in. What?

01-21-2013, 06:29 PM	#6
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19 Original Poster	Originally posted by Na Horuk Usually we get Canon shooters that want Pentax lenses,. Ha - guilty I own three canon dslrs and a ton of pentax glass - both m42 and K-mount - which is why buying the k-01 was an easy decision at the recent price drop. I have a couple of really nice FD lenses that I think would be amazing on the Pentax - there has to be something - On another note, I have some enlarger lenses (M39) arriving soon - I think I will need a bellows to make them work on the k-01 - that will be another thread Im sure : thanks for your reply

01-21-2013, 06:32 PM - 1 Like	#7
Swift1 Veteran Member Join Date: Sep 2009 Location: Oregon Photos: Gallery \| Albums Posts: 5,079	FD lenses are not adaptable to K-mount without the use of glass elements or without losing infinity focus. The K-01 uses the old K-mount and retains the flange distance which is longer than the flange distance of the FD mount. I believe that Pentax and Nikon use nearly the same flange distance which is one of the longest of all the major 35mm SLR mounts. I've read that the K mount and F mount are so similar that you can mount F mount lenses directly to the K mount ( I haven't tried and I'd do more research before trying)

01-21-2013, 06:49 PM	#9
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19 Original Poster	Thanks for the info. I appreciate it.

01-24-2013, 04:03 PM	#11
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	There is a thread that discusses all adaptors that can be used to mount various things to Pentax K mount bodies https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html Just for info, I have a Nikon to PK and Canon FD to PK adaptors, the Nikon adaptor has a 1.25 magnification and the canon has a 1.45 magnification to sort out infinity focus. Wide open on cheap lenses these adaptors produce a lot of softness and bleeding of colors at edges, but stopped down they are not too bad. The bigger issue is the internal infinity focus elements add focal length, so they are really only suitable for tele lenses

01-24-2013, 04:38 PM	#12
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,476	Originally posted by Lowell Goudge There is a thread that discusses all adaptors that can be used to mount various things to Pentax K mount bodies https://www.pentaxforums.com/forums/pentax-camera-field-accessories/96884-ada...addiction.html Just for info, I have a Nikon to PK and Canon FD to PK adaptors, the Nikon adaptor has a 1.25 magnification and the canon has a 1.45 magnification to sort out infinity focus. Wide open on cheap lenses these adaptors produce a lot of softness and bleeding of colors at edges, but stopped down they are not too bad. The bigger issue is the internal infinity focus elements add focal length, so they are really only suitable for tele lenses I think I said all that https://www.pentaxforums.com/forums/pentax-k-01/212701-fd-lens-k-01-without-g...ml#post2249438

01-24-2013, 06:37 PM	#13
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19 Original Poster	Originally posted by cyclone3d Actually, IF you can adjust the helicoid for infinity focus, you should be able to adapt it to K-mount no problem. It is going to be lens specific though AND you would need to physically replace the mount to be able to even possibly get infinity focus as the FD register distance is 3.46mm shorter than the Pentax register distance. I have done this with a Konica 58mm 1.4 lens and was able to get infinity focus on my K10d. With the K-01 it would have been easier becaue I would not have had to file away at the ring that hold in the rear piece of glass in order to clear the mirror. It is not possible with an adapter, but with physically modifying the lens, it may be possible. BTW, flanged M42 to K mount adapters work great as replacement mounts for converting lenses. After looking at the register distance chart again, it really looks to me like FD lenses should be easier to convert than Konica lenses. The Konica lenses have an almost 5mm register distance difference compared to the "only" 3.46mm register distance difference of the FD lenses. Camera Mounts Sorted by Register Interesting - thank you. I have an 50mm/ 1.8 I dont care for or need that I could test with first.

01-24-2013, 06:39 PM	#14
dmb video New Member Join Date: Jan 2013 Location: St.Albert Posts: 19 Original Poster	Thank you as well boriscleto and lowell

01-24-2013, 07:35 PM	#15
digital029art Inactive Account Join Date: Jan 2011 Posts: 440	The longer tele FD lenses like the 400/4.5 can be (relatively) easily converted to a K mount flange once you take off the FD mount & associated parts. It's amazing how much space (thickness) the FD mount takes up! Really complicated linkage the FD is .. so the hardest part is linking up the aperture ring back to work the iris. Kudos to Canon for switching to EOS years ago & for making excellent manual telephotos available for cheap!