Using 'other' lens on Pentax K-X?

dinneenp · 05-08-2010, 03:16 PM

HI,,
I'm looking to get a Tamron 18-250 lens and noticed they're a fair bit more expensive for Pentax fit.
Can I user other (Canon etc) lens with an adaptor?
If so-
what kind of price are they
easy to get(ebay?)
anthing to note/look out for?
any downsides to it?

If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper?

I've seen this one but it's old, I'm loking for a definitive full answer.

Thanks,
Patrick.

**boriscleto** · 05-08-2010, 03:29 PM

https://www.pentaxforums.com/forums/camera-studio-accessories/96884-adapters-...addiction.html

Keep in mind, with adapters you will not have autofocus and it will be stop down metering only. Nikon F and Canon FD adapters are useless for wide angle.

Ben_Edict · 05-08-2010, 03:46 PM

Originally posted by dinneenp

HI,,
I'm looking to get a Tamron 18-250 lens and noticed they're a fair bit more expensive for Pentax fit.
Can I user other (Canon etc) lens with an adaptor?
If so-
what kind of price are they
easy to get(ebay?)
anthing to note/look out for?
any downsides to it?

If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper?

I've seen this one but it's old, I'm loking for a definitive full answer.

Thanks,
Patrick.

The full answer is: NO.

Canon EF mount has a shorter flange to sensor distance than Pentax - so no infinity focus. Ofcourse you do not have AF, not aperture controle - in short, what would make the lens worth to use. On top any adapter, that would be useable, must contain a relay lens, in order to allow infinity focus. That relay lens will futher degrade the image quality of a already compromised lens. But ofcourse this (then expensive) adapter will still not give you AF or aperture control.

Using an adapter would be more expensive, than buying the lens in Pentax mount and it will render the lens quite useless.

You CAN use easily any old K-mount lens, any M42 lens with a M42-K adapter and any T2 lens or Tamron Adaptall or T4 mount lens with the appropriate adapters. Some old Nikon F-mount lenses will also fit the Pentax K-mount. In all cases: no AF, no aperture controle, everything fully manual.

And the good news is: Pentax is by far the make which works best with many old lenses. Users of Canon and Sony etc. will have much less convenience, because Pentax does at least support either Av mode or the semi-Av mode (Green Button) and AF-confirmation.

The thread you refer to is still valid, by the way - but you'll find much more info, if you look into the stickies and older threads about "old lenses on Pentax DSLRs".

Ben

dinneenp · 05-08-2010, 03:57 PM

Thanks- that answers it for me so.
save for the Pentax fit.
Abes of Maine have the 18-250 on back order for $329 bu tI don't think I'd trust that, after hearing stories, espically as it's backorder....

nulla · 05-09-2010, 12:51 AM

wrong thread... sorry please ignore this post

hcc · 05-09-2010, 04:41 AM

Originally posted by dinneenp

Thanks- that answers it for me so.
save for the Pentax fit.
Abes of Maine have the 18-250 on back order for $329 bu tI don't think I'd trust that, after hearing stories, espically as it's backorder....

I would add to the other earlier posts:
- buy a Pentax mount lens,
- do not back order a 18-250mm because the DA18-250mm is discontinued and Tamron no longer manusfacture the 18-250mm,
- consider the Pentaxforums.com marketplace, keh.com or ebay.

Mike Cash · 05-09-2010, 05:19 AM

Originally posted by dinneenp

If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper?

When I was a very young and freshly married man I made the mistake of insisting to my wife that generic brand sanitary napkins would be just as good as the name-brand items. After all, they all sit in the same place and perform the same function. No difference between them........right?

Please don't make the mistake of considering lenses to be accessories that you hang on the front of your camera. The truth of the matter is that cameras are accessories you hang on the back of your lenses.

dinneenp · 05-09-2010, 05:59 AM

Originally posted by hcc

- do not back order a 18-250mm because the DA18-250mm is discontinued and :

When you say back order you mean order from a site (like Abes of Maine, that have it on their site on 'back order') you mean because there's no deliveries awaiting cos they don't make it anymore?

One more quesiton- is the 28-250 lens for other makes the exact same (expect fit)? Just asking as a friend has the lens Canon fit so I'm going to play around with it.

Cheers,
Pa.

hcc · 05-13-2010, 01:42 AM

Originally posted by dinneenp

When you say back order you mean order from a site (like Abes of Maine, that have it on their site on 'back order') you mean because there's no deliveries awaiting cos they don't make it anymore?

Yes. They might not be able to satisfy your backorder, but you are locked with your order. Try instead to buy 2nd hand a Tamron 18-250mm (as good as Pentax DA18-250mm) that is more often available on the end hand market.

05-08-2010, 03:16 PM	#1
dinneenp Senior Member Join Date: Mar 2010 Location: ireland Photos: Gallery \| Albums Posts: 166	Using 'other' lens on Pentax K-X? HI,, I'm looking to get a Tamron 18-250 lens and noticed they're a fair bit more expensive for Pentax fit. Can I user other (Canon etc) lens with an adaptor? If so- what kind of price are they easy to get(ebay?) anthing to note/look out for? any downsides to it? If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper? I've seen this one but it's old, I'm loking for a definitive full answer. Thanks, Patrick.

05-09-2010, 12:51 AM	#5
nulla Veteran Member Join Date: Jul 2008 Location: Melbourne Australia Posts: 1,560	wrong thread... sorry please ignore this post Last edited by nulla; 05-09-2010 at 02:34 PM.

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05-08-2010, 03:29 PM	#2
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,477	https://www.pentaxforums.com/forums/camera-studio-accessories/96884-adapters-...addiction.html Keep in mind, with adapters you will not have autofocus and it will be stop down metering only. Nikon F and Canon FD adapters are useless for wide angle.

05-08-2010, 03:46 PM	#3
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	Originally posted by dinneenp HI,, I'm looking to get a Tamron 18-250 lens and noticed they're a fair bit more expensive for Pentax fit. Can I user other (Canon etc) lens with an adaptor? If so- what kind of price are they easy to get(ebay?) anthing to note/look out for? any downsides to it? If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper? I've seen this one but it's old, I'm loking for a definitive full answer. Thanks, Patrick. The full answer is: NO. Canon EF mount has a shorter flange to sensor distance than Pentax - so no infinity focus. Ofcourse you do not have AF, not aperture controle - in short, what would make the lens worth to use. On top any adapter, that would be useable, must contain a relay lens, in order to allow infinity focus. That relay lens will futher degrade the image quality of a already compromised lens. But ofcourse this (then expensive) adapter will still not give you AF or aperture control. Using an adapter would be more expensive, than buying the lens in Pentax mount and it will render the lens quite useless. You CAN use easily any old K-mount lens, any M42 lens with a M42-K adapter and any T2 lens or Tamron Adaptall or T4 mount lens with the appropriate adapters. Some old Nikon F-mount lenses will also fit the Pentax K-mount. In all cases: no AF, no aperture controle, everything fully manual. And the good news is: Pentax is by far the make which works best with many old lenses. Users of Canon and Sony etc. will have much less convenience, because Pentax does at least support either Av mode or the semi-Av mode (Green Button) and AF-confirmation. The thread you refer to is still valid, by the way - but you'll find much more info, if you look into the stickies and older threads about "old lenses on Pentax DSLRs". Ben

05-08-2010, 03:57 PM	#4
dinneenp Senior Member Join Date: Mar 2010 Location: ireland Photos: Gallery \| Albums Posts: 166 Original Poster	Thanks- that answers it for me so. save for the Pentax fit. Abes of Maine have the 18-250 on back order for $329 bu tI don't think I'd trust that, after hearing stories, espically as it's backorder....

05-09-2010, 04:41 AM	#6
hcc Pentaxian Join Date: Nov 2009 Location: Brisbane, Australia Photos: Gallery \| Albums Posts: 4,005	Originally posted by dinneenp Thanks- that answers it for me so. save for the Pentax fit. Abes of Maine have the 18-250 on back order for $329 bu tI don't think I'd trust that, after hearing stories, espically as it's backorder.... I would add to the other earlier posts: - buy a Pentax mount lens, - do not back order a 18-250mm because the DA18-250mm is discontinued and Tamron no longer manusfacture the 18-250mm, - consider the Pentaxforums.com marketplace, keh.com or ebay.

05-09-2010, 05:19 AM	#7
Mike Cash Veteran Member Join Date: Jan 2007 Location: Japan Photos: Gallery Posts: 6,950	Originally posted by dinneenp If it works then why would someone pay $$$ for an FA 50mm 1.4/1.7 lens when you could buy other brand a lot cheaper? When I was a very young and freshly married man I made the mistake of insisting to my wife that generic brand sanitary napkins would be just as good as the name-brand items. After all, they all sit in the same place and perform the same function. No difference between them........right? Please don't make the mistake of considering lenses to be accessories that you hang on the front of your camera. The truth of the matter is that cameras are accessories you hang on the back of your lenses.

05-09-2010, 05:59 AM	#8
dinneenp Senior Member Join Date: Mar 2010 Location: ireland Photos: Gallery \| Albums Posts: 166 Original Poster	Originally posted by hcc - do not back order a 18-250mm because the DA18-250mm is discontinued and : When you say back order you mean order from a site (like Abes of Maine, that have it on their site on 'back order') you mean because there's no deliveries awaiting cos they don't make it anymore? One more quesiton- is the 28-250 lens for other makes the exact same (expect fit)? Just asking as a friend has the lens Canon fit so I'm going to play around with it. Cheers, Pa.

05-13-2010, 01:42 AM	#9
hcc Pentaxian Join Date: Nov 2009 Location: Brisbane, Australia Photos: Gallery \| Albums Posts: 4,005	Originally posted by dinneenp When you say back order you mean order from a site (like Abes of Maine, that have it on their site on 'back order') you mean because there's no deliveries awaiting cos they don't make it anymore? Yes. They might not be able to satisfy your backorder, but you are locked with your order. Try instead to buy 2nd hand a Tamron 18-250mm (as good as Pentax DA18-250mm) that is more often available on the end hand market.