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02-11-2011, 02:14 AM   #1
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lenses for K-x

Hi there,

I'd just like some information about specifically what lenses can be used for a K-x. Is there a database out there somewhere? I have read that any k mount lens will fit, but are there other mounts that will also fit? I am a newbie and I don't know the first thing to look for when considering purchasing other lenses for my camera. I do know a little (such as the f value) because I am searching for a good prime lens at the moment. Any help is more than welcome.

02-11-2011, 02:19 AM   #2
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To go for other mounts you will need adapter, the best would be Pentax M42 to K Adapter for old M42 screw lenses. Secondhand 50mm prime is one of the cheapest options to start. I would start with K mount.


Last edited by arv; 02-11-2011 at 02:56 AM.
02-11-2011, 02:48 AM   #3
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Thanks, that is quite helpful. I am also wondering about something that would include third party manufacturers' lens compatibility and not exclusively Pentax.
02-11-2011, 03:06 AM   #4
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you can use any lense of other manufacturer, all you need is the lense to be on "K mount"*.

Sigma, Tamron, etc ... do some lenses for Pentax mount, but also for Canon or Nikon, for exemple. But every time, they mentionned for wich brand or mount its made for.

*when it's written "mount K M", "mount K A", "mount K AF"," mount k AF˛", "mount K AF3", it's also fully compatible with your K-x. they just mean, that their are some few option linked to the mount (A for aperture controlle by the body, K AF means motorized.)

02-11-2011, 03:44 AM   #5
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Lens compatibility is one of the great things about Pentax and much better than most other brands!

I really enjoy shooting with a variety of older lenses myself - just for fun (and its cheap!).

Pretty much any K mount lense made works with the K-x and also M42 lenses with an adaptor (which is cheap).
02-12-2011, 05:06 PM   #6
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I believe the responses above, particularly ARV’s link, summarizes it all. However, as a precaution in case you haven’t come across the topic, there are old third party lenses (as well as the Ricoh Rikenons themselves) equipped with what is known to the Pentax world as the “Dreaded Ricoh Pin”, which can get a lens stuck on a Pentax AF body. Thanks to this forum I never had to experience this issue with my K-x and old primes. The good news is a number of people had pointed out not all lenses with this Ricoh pin will get stuck. I bought a Vivitar 28-80 designated as a PK-A/R mount and had the infamous pin. The seller claimed she used it on a K10D without issues but I removed the pin anyway just to be on the safe side. This subject has been discussed extensively on this forum I recommend searching (or Google) the words “Ricoh Pin”. I hope this helps...Cheers!
02-13-2011, 03:54 PM   #7
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A vast number of lenses are Kx-compatible, one way or another. Even more, aren't. Some few types can be more-or-less easily adapted for your Kx. Most, can't. Here is my overview:

* Virtually anything ever made by Asahi / Pentax. There are maybe 3 very rare exceptions.

* Virtually anything from any maker that is labeled as PK, PKA, KA, KR, KAR, KAF, etc. Beware the 'Ricoh-ish' KR and KAR lenses, as noted above. And a few Vivitar lenses have a too-deep link shield, as mentioned. Both of those problems are fixable.

* Virtually any M42 screwmount lens, via an M42-PK adapter. But those with a auto-aperture pin but without an M/A switch only work wide-open, unless that pin is glued down, which reduces the value of the lens.

* Some few Russian lenses with an M39 screwmount. Unfortunately, M39 looks exactly like L39, which WON'T work on Pentax. If a lens is marketed for Pentax-Praktica, fine. If not, then not so fine.

* Many larger MF (medium format - 645, 6x6, 6x7, 6x9) and LF (large format) lenses, using PK adapters. But those adapters tend to be expensive, and the lenses tend to be large.

* Lenses without focusing mechanisms, like enlarger and bellows-macro and projector lenses, via extension tubes and/or bellows. Such lenses longer than 80mm can probably reach infinity-focus on bellows and so can be used for general photography. Shorter lenses, and camera lenses from almost any maker, can also be used on extension, but only for macros or closeups. And virtually any optical material can be stuffed into a bellows for experimentation.

* I'm no machinist, but I've successfully modified old manual primes with Nikon, Olympus OM, Contax/Yashica C/Y, and Exakta mounts, to work (with infinity focus) on my K20D. Certain Minolta MC/MD lenses *may* be adaptable without major surgery.

* Any other camera lenses either require optical adapters (which reduce image quality), or an expensive adaptation kit (such as a Leitax), or rather major surgery. These include Canon, Nikon AF, Leica, Konica, Minolta AF, and most other mount types.

Last edited by RioRico; 02-13-2011 at 04:00 PM.

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