Canon Lens to Pentax Adapter/converter

mrg9999 · 12-31-2016, 06:48 PM

Happy 2017

I know this has probably been discussed a few times.
Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where?

I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out.

Imp · 12-31-2016, 06:56 PM - **1 Like**

No can do canon flange distance is shorter than Pentax k. Unless there is an adapter with a glass element?

reh321 · 12-31-2016, 07:03 PM - **1 Like**

Originally posted by mrg9999

Happy 2017

I know this has probably been discussed a few times.
Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where?

I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out.

There are two completely different Canon lens mounts modern EF-mount and the FD-mount that preceded it - you would need one matching whichever type of lens you have.

robthebloke · 12-31-2016, 08:00 PM - **1 Like**

No. You can adapt Pentax k to canon, but not the other way around.

**PJ1** · 12-31-2016, 08:01 PM - **2 Likes**

Pentax K mount has a registration distance of 45.46mm. Canon FD is 42mm and Canon EOS is 44mm. Because of the shorter registration distance, a Canon lens would have to extend back inside the body and it would stop the mirror from operating. The only other option (as stated above) is an adapter with a glass element. This would probably reduce image quality.

An alternative is to use a reversing mount which screws onto the filter threads. This would allow you to shoot macro.

**UncleVanya** · 12-31-2016, 11:55 PM - **1 Like**

Non-glassed or deglassed adapters can be used for macro even without reversing. You can't get infinity focus without a glass based adapter that acts like a teleconverter. Most are very low optical quality and not worth the effort.

mrg9999 · 01-01-2017, 03:27 AM

Thanks all who replied.
I have an MD adapter for pentax that works, but couldn't find an EOS to MD either. Looks like I'm either going to have to get an EOS to try these "lenses of a lifetime"

Imp · 01-01-2017, 06:25 AM

Oh the horror!

Not a Number · 01-01-2017, 08:29 AM

The EOS (EF) lenses have neither aperture rings nor levers so you couldn't set or stop down the lenses using an adapter. You can use an EOS body, set the aperture, stop down, and dismount the lens which leaves it at the set aperture. But then you'd have to have a Canon body so why bother?

There are (glassed) adapters for Canon FD (manual focus) lenses to K-mount. These will incur some loss of image quality but it up to the individual if the results are acceptable or not.

**UncleVanya** · 01-01-2017, 09:20 AM

Originally posted by Not a Number

The EOS (EF) lenses have neither aperture rings nor levers so you couldn't set or stop down the lenses using an adapter. You can use an EOS body, set the aperture, stop down, and dismount the lens which leaves it at the set aperture. But then you'd have to have a Canon body so why bother?

There are (glassed) adapters for Canon FD (manual focus) lenses to K-mount. These will incur some loss of image quality but it up to the individual if the results are acceptable or not.

M43 adapters that interface electronically exist. But no such adapter exists for Pentax.

**Lowell Goudge** · 01-01-2017, 02:41 PM

Originally posted by mrg9999

Happy 2017

I know this has probably been discussed a few times.
Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where?

I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out.

Yes there is. It is essentially a 1.4x teleconverter with optical elements that add magnification to correct the registry distance for infinity focus. They really bloom out and are soft when shooting wide open

12-31-2016, 06:48 PM	#1
mrg9999 New Member Join Date: Apr 2015 Photos: Albums Posts: 17	Canon Lens to Pentax Adapter/converter Happy 2017 I know this has probably been discussed a few times. Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where? I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out.

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12-31-2016, 06:56 PM - 1 Like	#2
Imp Pentaxian Join Date: Nov 2014 Location: Washington, DC Photos: Gallery \| Albums Posts: 1,749	No can do canon flange distance is shorter than Pentax k. Unless there is an adapter with a glass element?

12-31-2016, 07:03 PM - 1 Like	#3
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,181	Originally posted by mrg9999 Happy 2017 I know this has probably been discussed a few times. Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where? I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out. There are two completely different Canon lens mounts modern EF-mount and the FD-mount that preceded it - you would need one matching whichever type of lens you have.

12-31-2016, 08:00 PM - 1 Like	#4
robthebloke Veteran Member Join Date: Sep 2013 Location: Sydney Photos: Albums Posts: 844	No. You can adapt Pentax k to canon, but not the other way around.

12-31-2016, 08:01 PM - 2 Likes	#5
PJ1 Loyal Site Supporter Join Date: Jul 2012 Location: Toowoomba, Australia Photos: Gallery \| Albums Posts: 5,485	Pentax K mount has a registration distance of 45.46mm. Canon FD is 42mm and Canon EOS is 44mm. Because of the shorter registration distance, a Canon lens would have to extend back inside the body and it would stop the mirror from operating. The only other option (as stated above) is an adapter with a glass element. This would probably reduce image quality. An alternative is to use a reversing mount which screws onto the filter threads. This would allow you to shoot macro.

12-31-2016, 11:55 PM - 1 Like	#6
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Non-glassed or deglassed adapters can be used for macro even without reversing. You can't get infinity focus without a glass based adapter that acts like a teleconverter. Most are very low optical quality and not worth the effort.

01-01-2017, 03:27 AM	#7
mrg9999 New Member Join Date: Apr 2015 Photos: Albums Posts: 17 Original Poster	Thanks all who replied. I have an MD adapter for pentax that works, but couldn't find an EOS to MD either. Looks like I'm either going to have to get an EOS to try these "lenses of a lifetime"

01-01-2017, 06:25 AM	#8
Imp Pentaxian Join Date: Nov 2014 Location: Washington, DC Photos: Gallery \| Albums Posts: 1,749	Oh the horror!

01-01-2017, 08:29 AM	#9
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	The EOS (EF) lenses have neither aperture rings nor levers so you couldn't set or stop down the lenses using an adapter. You can use an EOS body, set the aperture, stop down, and dismount the lens which leaves it at the set aperture. But then you'd have to have a Canon body so why bother? There are (glassed) adapters for Canon FD (manual focus) lenses to K-mount. These will incur some loss of image quality but it up to the individual if the results are acceptable or not.

01-01-2017, 09:20 AM	#10
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by Not a Number The EOS (EF) lenses have neither aperture rings nor levers so you couldn't set or stop down the lenses using an adapter. You can use an EOS body, set the aperture, stop down, and dismount the lens which leaves it at the set aperture. But then you'd have to have a Canon body so why bother? There are (glassed) adapters for Canon FD (manual focus) lenses to K-mount. These will incur some loss of image quality but it up to the individual if the results are acceptable or not. M43 adapters that interface electronically exist. But no such adapter exists for Pentax.

01-01-2017, 02:41 PM	#11
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	Originally posted by mrg9999 Happy 2017 I know this has probably been discussed a few times. Is there an adapter that will convert a Canon lens to Pentax K, if so can someone let me know where? I have acquired a number of "nice" canon lenses and some for loan for a few months and I'd like to try them out. Yes there is. It is essentially a 1.4x teleconverter with optical elements that add magnification to correct the registry distance for infinity focus. They really bloom out and are soft when shooting wide open