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The Pentax K System: A Brief Overview


Pentax K mount, otherwise known as PK, has been the company’s SLR mount since 1975. Unlike many other mounts, numerous companies made cameras using the Pentax K mount instead of only creating lenses.

This wide use and long production period has made Pentax K one of the most popular and universal systems in photography today. Here, we’ll go over the mount and talk about what makes it special. Watch Nuno and Nico’s video below, or keep scrolling for the text version.

Additionally, check out our video on the Top 10 Pentax cameras of 2020! We gathered search result data and let the internet pick the most popular Pentax cameras!


The K mount was born out of cooperation between the Asahi Optical Company and Zeiss Ikon to create a shared mount that other companies could use. The two companies had a history together already, with Asahi Optical naming their first SLR Pentax as a portmanteau of Pentaprism and Contax. It was also possibly named this way because of the East German Zeiss rebrands known as Pentacon.

After the success of Pentax’s SLRs using the M42 thread mount Zeiss designed, Pentax and Zeiss Ikon intended to create a shared bayonet lens mount.

The idea was to take advantage of German design and heritage while utilizing Japanese manufacturing capacity. Zeiss would go on to do something very similar with Yashica, albeit after the collapse of Zeiss Ikon.

After the partnership fell apart, Pentax was left with the K mount and a few new lens designs, which they decided to continue developing.

The original K mount debuted in 1975 alongside the K series of SLRs, including the K2, KX, KM, and the K1000 a year later. These cameras were based on the same platform as the Spotmatic series, so they were quite large and heavy.

The arrival of compact SLRs like the Olympus OM-1 signaled a change in the market, so Pentax shifted gears almost immediately to offer their own compact SLR. The ME and MX arrived a year later in 1976.

The original K mount is capable of open-aperture metering and aperture-priority auto exposure. It is a simple three-bayonet system with a mechanical linkage to the aperture mechanism only.

In 1980 Pentax unveiled its first truly professional offering, the LX. It offered the same suite of accessories and customizability of its competitors, like the Canon New F-1 and Nikon F3, but was smaller and incorporated some impressive metering technology.

The LX read light off of the first shutter curtain in the same way as the Olympus OM-2. It also had more interchangeable finders and prisms than either the Canon or Nikon alternative.

By this time, Pentax had solidified its K mount SLRs as consumer standards, although the LX failed to wrest control of the professional market from Nikon.

In 1983, Pentax added functionality to the K mount in the form of a few electrical contacts. These contacts would allow for fully programmed exposure. This new mount variant was referred to as KA, and the cameras that came along with it were the A series.

The automation continued with the 1985 introduction of the P series, which had DX-coded ISO settings and exposure lock settings. These cameras were also made mainly of plastic.

1985 also saw the release of the Minolta Maxxum 7000, which ushered in the era of autofocus in 35mm cameras. It took Pentax two more years to incorporate autofocus into the K mount using an in-body motor similar to the pre-AF-S Nikon system. 

This is referred to as KAF mount, and released alongside the SF series of cameras. These cameras were also the first to feature built-in, retractable flashes with TTL and autofocus capabilities.

The next generation of cameras was called the Z series, and mostly added small improvements, like faster autofocus and support for power zoom lenses.

After the Z series came the MZ series, which brought Pentax back to its roots by focusing on small and light cameras. The M in the name mimics the earlier M series of compact SLRs.

They were ultra-compact and ultra-light compared to the competition, without sacrificing features. Cameras like the MZ-5 even retained manual dials for some functions, which has made them popular with a certain class of photographer.

With the transition to digital, Pentax retained strong support for older lenses by having large viewfinders and continuing to use the K mount in its current form, known as KAF4.


K mount lenses are some of the most varied, with almost 50 years of production time by a large number of manufacturers. Pentax themselves made multiple generations of each lens, from fisheyes to long telephotos. 

What differentiates K mount from other popular mounts, like Nikon, Canon FD, or Olympus, is that Pentax K was used by other manufacturers to make cameras instead of just lenses. Manufacturers like Chinon, Ricoh, Cosina, Miranda, Zenit, Sigma, and many others used the K mount for their camera bodies.

Because it was used so widely, there are a lot more lenses available for K mount than most other lenses, especially in “normal” focal lengths. Because Canon made all the bodies for Canon FD mount and sold those bodies with normal length lenses, most third party manufacturers avoided making these lenses for FD.

With K mount, however, manufacturers would construct and bundle their own lenses with their bodies. This leads to the K mount having a tremendous variety of lenses from an equally tremendous variety of manufacturers.

Manufacturers like Ricoh and Chinon in particular made quite a few K mount bodies and a large number of lenses to go along with them. Pentax would eventually end up being sold to Ricoh in 2007.

Ricoh even made their own modified version of the K mount, which allowed their cameras to use full-program exposure in a simpler way than the Pentax method. 

Lens Variants

Pentax-M Series

  • Full manual lens, with no A setting for aperture. 
  • Will work in full manual or aperture priority mode with most K mount cameras.

Pentax-A Series

  • Introduced A setting for aperture.
  • Will work in PSAM modes for cameras that are capable of that, otherwise will work identically to M series.

Pentax-FA Series

  • Introduced autofocus. Retained aperture ring.
  • Required an internal focusing motor for autofocus. Will work the same as Pentax-A lenses on older cameras.

Pentax-DA Series

  • Designed mostly for APS-C digital cameras, so sensor coverage is not always 100% on 35mm.
  • Removed aperture ring, further decreasing compatibility with older models. Only compatible with newer cameras capable of setting the aperture in-body.


Like with lenses, there are many K mount bodies out there, both Pentax and otherwise. As mentioned before, companies like Ricoh and Chinon made their own K mount bodies. Some of these, like the Chinon CE-4 and Ricoh XR7, offered great feature sets at low prices.

Within the Pentax realm, there are K mount bodies at all phases of SLR development. From the full-manual, all-metal K series to the new K-1 DSLR, Pentax has a camera to suit the needs of almost all photographers. 

Some notable standouts include the P30, the MX, the ME Super, the K2, the SFX, MZ-5, and the K1000. The K1000 in particular was a definitive SLR for Pentax, being sold until 1997 despite debuting in 1976.

The K1000’s long production run is a result of the camera achieving prestige as the go-to “student camera” for decades. The K1000 was an icon of simple, mechanical SLR design, and offered everything a burgeoning photographer may need. 

The K1000 retained its spot on top later in life by moving production away from Japan and lowering the quality of some materials. The body was always made with metal, though.

Body Variants

Original K

  • Aperture priority auto-exposure, no autofocus.
  • K1000, K2, MX, ME Super, etc.


  • PSAM exposure modes, no autofocus
  • Super A, Program Plus, etc.


  • PSAM exposure modes, autofocus
  • MZ-5, SFX, etc.

Who is it for? / Conclusions

As I’ve mentioned, the K mount is incredibly varied. Aside from Nikon F, it’s the longest-running single mount still in production today. Just like Nikon, it’s gone through a number of upgrades over the years.

Unlike Nikon, however, compatibility remains mostly intact with almost all lenses. While you may need to use stop-down metering to use a Pentax-M lens on a new digital body, it is possible. Current Pentax DSLRs still use the in-body focusing motors of older AF lenses as well. 

With this in mind, Pentax K is suitable for anyone. If you want a fully mechanical, manual SLR, you can pick up a K1000 or MX. If you want something more featured, but still manual and classic-feeling, you can get a P30 or Super A. For those who want a similar shooting style to a DSLR, there are great options like the MZ-5 or *IST.

Even in the digital space, you can expect strong compatibility with older lenses and rugged weather sealing with cameras like the K-1II or K-70.

To sum it up, it’s hard not to recommend the K mount. It’s a classic, and it’s worthy of your photographic attention in all of its iterations.

Filmi, Technical/Educational

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