Converters from Nikon or Canon to Pentax mount

Richard B 13 · 12-12-2016, 07:04 PM

I know they make converters from a Nikon or Canon Lens that will fit a Pentax mount. I was wondering what people thought of them? Any down grading of the photograph loss of mm , f stop or anything else?

Adam · 12-12-2016, 07:06 PM

They act as teleconverters, so there's a loss in image quality sadly. Generally speaking, therefore, those lenses can't be reliably used.

**boriscleto** · 12-12-2016, 07:29 PM

https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/96884-...sions-lba.html

JeffB · 12-12-2016, 08:16 PM

I know price is not always an indicator of quality. But I've never seen any "high-end" adapters to Pentax K mount. My basis for pricing is simply the going rate for know good quality teleconverters ~$100-$400+. I've only ever seen ~$30-40 Nikon lens to Pentax body converters. So my feeling is the glass quality of the elements is pretty low.

If you are into cross platform lens experimentation without any alteration of image quality you need lenses with a longer registration distance than the camera. So medium format lenses can be plugged into most APS or 35mm sensor DSLRs by simple tube adapters having no glass. You just crop the image circle.

Canon is the only DSLR platform where you can (sort of) easily adapt other SLR lenses without intervening elements because Canon's sensor to mount registration distance is the shortest of any maker.

MIrrorless offers lots of possible adaptations of 35mm lenses because all mirrorless bodies have a much shorter registration than the DSLR bodies.

**UncleVanya** · 12-12-2016, 08:35 PM

Pre-ai lenses will fit the Pentax k mount without an adapter. Fitting the lens is a bit less secure (partial turn maybe 1/4 turn, not locked). Some rear guards or odd lenses could interfere be careful when trying this.

Alternately look up the adaptist mount replacement part. That permits a number of lens types to fit the k mount without optics.

**lithedreamer** · 12-12-2016, 09:17 PM

Dumb question: is the K-01 any more adaptable, since it's a mirrorless camera, or is it the same because it maintains mount compatibility with the K-mount?

Scintilla · 12-12-2016, 09:18 PM

Originally posted by JeffB

Canon is the only DSLR platform where you can (sort of) easily adapt other SLR lenses without intervening elements because Canon's sensor to mount registration distance is the shortest of any maker.

And because their mount's throat is so wide, at 54mm in diameter. If flange focal distance was the only consideration, you'd think Sigma SA-mount having just as short a flange focal distance as Canon EF would have lots of adapters (and let's face it, they need it a lot more than Canon). But they don't, because their bayonet is mechanically the same as Pentax K, so the diameter is only 44mm -- not really wide enough to adapt anything except M42. (Source: here.)

Consider also Sony/Minolta Alpha-mount (FFD = 44.5mm, diameter = 49.7mm). The FFD difference between A-mount and, say, Olympus OM or Contax/Yashica is 1.5mm, roughly the same as the difference between Canon EF and Pentax K, for which glassless adapters do exist. Yet the only OM-or-C/Y-to-A adapters out there have glass. Heck, even with Leica R, with a full 2.5mm longer FFD than A-mount, you need to buy a mount replacement kit rather than a simple adapter.

**UncleVanya** · 12-12-2016, 09:39 PM

Originally posted by lithedreamer

Dumb question: is the K-01 any more adaptable, since it's a mirrorless camera, or is it the same because it maintains mount compatibility with the K-mount?

The same as any k mount camera.

---------- Post added 12-12-16 at 11:41 PM ----------

Canon lengthened their mount rendering all their old glass unusable which is why the FD FL and FDn glass took off on early mirror less offerings.

Richard B 13 · 12-13-2016, 03:05 AM

I just wanted to thank you all for being so quick on this subject.

**Mallee Boy** · 12-13-2016, 06:48 PM

Yep...all good advice. Sitting here negotiating a return of a K mount to Nikon F adapter to an ebay supplier right now. It fits on the Nikon just fine....but the Pentax lenses either will not fit at all or do not lock in position, turning around in the mount at will. So its going back. B&H have one that seems to get reasonable reviews, so if I get my money back I will check that out.

**UncleVanya** · 12-14-2016, 07:44 AM

Originally posted by Mallee Boy

Yep...all good advice. Sitting here negotiating a return of a K mount to Nikon F adapter to an ebay supplier right now. It fits on the Nikon just fine....but the Pentax lenses either will not fit at all or do not lock in position, turning around in the mount at will. So its going back. B&H have one that seems to get reasonable reviews, so if I get my money back I will check that out.

Glass type (teleconverter) adapter?

**boriscleto** · 12-14-2016, 05:41 PM

Originally posted by UncleVanya

Glass type (teleconverter) adapter?

It would have to be. Nikon has a longer FFD than Pentax...really everybody except Leica R...

**UncleVanya** · 12-15-2016, 01:01 AM

Originally posted by boriscleto

It would have to be. Nikon has a longer FFD than Pentax...really everybody except Leica R...

Not really. I have a friend who has a glassless one he used only for macro takumar. Granted it is quite a limited use option.

**boriscleto** · 12-15-2016, 08:50 AM

Originally posted by UncleVanya

Not really. I have a friend who has a glassless one he used only for macro takumar. Granted it is quite a limited use option.

My Canon FD adapter becomes a glassless adapter just by unscrewing the glass...

**UncleVanya** · 12-15-2016, 09:06 AM

Originally posted by boriscleto

My Canon FD adapter becomes a glassless adapter just by unscrewing the glass...

I had seen some of these myself - my friends adapter was without glass from ebay but could have started life with glass I guess...

12-12-2016, 07:04 PM	#1
Richard B 13 Junior Member Join Date: Apr 2014 Posts: 48	Converters from Nikon or Canon to Pentax mount I know they make converters from a Nikon or Canon Lens that will fit a Pentax mount. I was wondering what people thought of them? Any down grading of the photograph loss of mm , f stop or anything else?

12-12-2016, 07:06 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	They act as teleconverters, so there's a loss in image quality sadly. Generally speaking, therefore, those lenses can't be reliably used. 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:

12-13-2016, 03:05 AM	#9
Richard B 13 Junior Member Join Date: Apr 2014 Posts: 48 Original Poster	Thank you all I just wanted to thank you all for being so quick on this subject.

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12-12-2016, 07:29 PM	#3
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/96884-...sions-lba.html

12-12-2016, 08:16 PM	#4
JeffB Senior Member Join Date: Nov 2009 Location: 'Merica! Posts: 209	I know price is not always an indicator of quality. But I've never seen any "high-end" adapters to Pentax K mount. My basis for pricing is simply the going rate for know good quality teleconverters ~$100-$400+. I've only ever seen ~$30-40 Nikon lens to Pentax body converters. So my feeling is the glass quality of the elements is pretty low. If you are into cross platform lens experimentation without any alteration of image quality you need lenses with a longer registration distance than the camera. So medium format lenses can be plugged into most APS or 35mm sensor DSLRs by simple tube adapters having no glass. You just crop the image circle. Canon is the only DSLR platform where you can (sort of) easily adapt other SLR lenses without intervening elements because Canon's sensor to mount registration distance is the shortest of any maker. MIrrorless offers lots of possible adaptations of 35mm lenses because all mirrorless bodies have a much shorter registration than the DSLR bodies.

12-12-2016, 08:35 PM	#5
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,404	Pre-ai lenses will fit the Pentax k mount without an adapter. Fitting the lens is a bit less secure (partial turn maybe 1/4 turn, not locked). Some rear guards or odd lenses could interfere be careful when trying this. Alternately look up the adaptist mount replacement part. That permits a number of lens types to fit the k mount without optics.

12-12-2016, 09:17 PM	#6
lithedreamer Site Supporter Join Date: Sep 2013 Photos: Gallery \| Albums Posts: 1,799	Dumb question: is the K-01 any more adaptable, since it's a mirrorless camera, or is it the same because it maintains mount compatibility with the K-mount?

12-12-2016, 09:18 PM	#7
Scintilla Veteran Member Join Date: Oct 2013 Photos: Gallery \| Albums Posts: 347	Originally posted by JeffB Canon is the only DSLR platform where you can (sort of) easily adapt other SLR lenses without intervening elements because Canon's sensor to mount registration distance is the shortest of any maker. And because their mount's throat is so wide, at 54mm in diameter. If flange focal distance was the only consideration, you'd think Sigma SA-mount having just as short a flange focal distance as Canon EF would have lots of adapters (and let's face it, they need it a lot more than Canon). But they don't, because their bayonet is mechanically the same as Pentax K, so the diameter is only 44mm -- not really wide enough to adapt anything except M42. (Source: here.) Consider also Sony/Minolta Alpha-mount (FFD = 44.5mm, diameter = 49.7mm). The FFD difference between A-mount and, say, Olympus OM or Contax/Yashica is 1.5mm, roughly the same as the difference between Canon EF and Pentax K, for which glassless adapters do exist. Yet the only OM-or-C/Y-to-A adapters out there have glass. Heck, even with Leica R, with a full 2.5mm longer FFD than A-mount, you need to buy a mount replacement kit rather than a simple adapter.

12-12-2016, 09:39 PM	#8
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,404	Originally posted by lithedreamer Dumb question: is the K-01 any more adaptable, since it's a mirrorless camera, or is it the same because it maintains mount compatibility with the K-mount? The same as any k mount camera. ---------- Post added 12-12-16 at 11:41 PM ---------- Canon lengthened their mount rendering all their old glass unusable which is why the FD FL and FDn glass took off on early mirror less offerings.

12-13-2016, 06:48 PM	#10
Mallee Boy Site Supporter Join Date: Sep 2006 Location: South Australia Photos: Gallery \| Albums Posts: 3,904	Yep...all good advice. Sitting here negotiating a return of a K mount to Nikon F adapter to an ebay supplier right now. It fits on the Nikon just fine....but the Pentax lenses either will not fit at all or do not lock in position, turning around in the mount at will. So its going back. B&H have one that seems to get reasonable reviews, so if I get my money back I will check that out.

12-14-2016, 07:44 AM	#11
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,404	Originally posted by Mallee Boy Yep...all good advice. Sitting here negotiating a return of a K mount to Nikon F adapter to an ebay supplier right now. It fits on the Nikon just fine....but the Pentax lenses either will not fit at all or do not lock in position, turning around in the mount at will. So its going back. B&H have one that seems to get reasonable reviews, so if I get my money back I will check that out. Glass type (teleconverter) adapter?

12-14-2016, 05:41 PM	#12
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	Originally posted by UncleVanya Glass type (teleconverter) adapter? It would have to be. Nikon has a longer FFD than Pentax...really everybody except Leica R...

12-15-2016, 01:01 AM	#13
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,404	Originally posted by boriscleto It would have to be. Nikon has a longer FFD than Pentax...really everybody except Leica R... Not really. I have a friend who has a glassless one he used only for macro takumar. Granted it is quite a limited use option.

12-15-2016, 08:50 AM	#14
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	Originally posted by UncleVanya Not really. I have a friend who has a glassless one he used only for macro takumar. Granted it is quite a limited use option. My Canon FD adapter becomes a glassless adapter just by unscrewing the glass...

12-15-2016, 09:06 AM	#15
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,404	Originally posted by boriscleto My Canon FD adapter becomes a glassless adapter just by unscrewing the glass... I had seen some of these myself - my friends adapter was without glass from ebay but could have started life with glass I guess...