Pentax Lenses: Compatible Cameras For Your Photography Needs

Pentax cameras are known for their ability to use older lenses. The K-mount series, including the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimised), and FA (full-frame) series, are all compatible with current Pentax DSLRs. However, older lenses may have limitations with certain camera functions, and some newer lenses may not work with older camera bodies. Pentax K-mount lenses are also compatible with autofocusing, focus confirmation, metering, and IS.

Pentax K-mount Lens Compatibility

Overview

Most Pentax lenses are compatible with most Pentax cameras. However, there are some exceptions and limitations with certain lenses. It is always a good idea to check compatibility before buying a lens.

K-mount Series

There are several series of Pentax K-mount lenses, including the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimised), and FA (full-frame) series. While all Pentax K-mount lenses ever produced are compatible with all current Pentax DSLRs, there are restrictions in that not all exposure modes of the camera are supported by old lenses. Some of the newer lenses do not work with older cameras.

K and M Series

The K and M series do not have aperture contacts, so they do not work with Av and Tv mode. You will need to use M mode, but you will get meter readings. You can also get a meter reading suggestion by pushing the +/- or green button, depending on the camera model and settings. Metering on these digital SLRs tends to be noticeably more inconsistent than on the film SLRs they were designed for. These two series do not get matrix metering, just centre-weighted and spot metering, but do get focus-trap.

KR-mount Series

There is also a rare breed of K-mount called the KR-mount, used by Ricoh. They have an extra pin which will get stuck unless removed.

M42 Screw-mount Series

Before K-mount, Pentax used a screw-mount called M42. Adapters are available from Pentax and third parties to use these lenses with Pentax cameras. With third-party adapters, make sure it is of the thin makes-even-surface-with-bayonet design. The ones that have a metal layer over the bayonet will not let your M42 lens focus to infinity.

M37 Screw-mount Series

Technically, the M37 screw-mount can also be attributed to Pentax, although the company was named Asahi Optical Corporation at the time. Adapters are scarce; you would most likely find an M37-to-M42 adapter, which would then also need to be used with an M42-to-K-mount adapter.

Pentax K-mount Lens Series

The Pentax K-mount Lens Series is a series of lenses produced by Pentax that are compatible with all current Pentax DSLRs. The series includes the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimised), and FA (full-frame) lenses. While all Pentax K-mount lenses are compatible with current Pentax DSLRs, there are restrictions on older lenses, as not all exposure modes are supported.

The K-mount lenses are also compatible with autofocusing, focus confirmation, metering, and IS. The two oldest series, the K and M series, do not have aperture contacts and therefore do not support Av and Tv modes. Instead, these series must be used in M mode, but will provide meter readings. The K and M series also only support centre-weighted and spot metering, not matrix metering.

In addition to the K-mount, Pentax has also used screw-mounts, known as M42, and the 645 and 67 medium format mounts. Adapters are available for these lenses, although they are not always necessary, as some M42 lenses can be mounted directly to K-mount cameras.

Pentax K-mount Lens Exceptions

The Pentax K-mount is a bayonet lens mount standard for mounting interchangeable photographic lenses to 35mm single-lens reflex (SLR) cameras. It was created by Pentax in 1975 and has since been used by all Pentax 35mm and digital SLRs, as well as the MILC Pentax K-01.

The Pentax K-mount has undergone several evolutions over the years as new functionality has been added. The term K-mount may refer to the original K-mount or to all its variations. The original K-mount is a simple bayonet connection with three tabs. The lens is locked into the camera with a 70-degree clockwise turn (when looking at the front of the camera).

While all Pentax K-mount lenses ever produced are compatible with all current Pentax DSLRs, there are some exceptions and variations to note:

• FA and F "soft" lenses behave like M lenses in terms of metering.
• Some newer lenses do not work with older cameras.
• Some older lenses do not work with newer cameras or have limited functionality. For example, pre-A lenses can only be used in manual stop-down metering mode and manual flash mode on certain cameras.
• Certain camera bodies lack the ability to read the position of the aperture simulator, resulting in "stopped-down" metering.
• The KAF4 mount, introduced in 2016, is identical to the KAF3 mount but lacks the aperture control lever. Aperture control information is transmitted digitally, and the aperture is stopped down through a motor built into the lens.
• The "crippled" K-mount refers to digital K-mount Pentax SLR bodies and some lower-end film cameras that lack the ability to read the position of the aperture simulator. Lenses that lack the lens information contacts introduced with the KA-mount do not support open-aperture metering on these bodies.
• The R-K-mount is a variation of the original K-mount by Ricoh, supporting its own implementation of shutter priority and auto-exposure modes.
• The KF-mount was Pentax's first attempt at an autofocus system but was largely a failure, with only one camera and one lens ever using this mount.
• The KA-mount is derived from the original K-mount and allows the lens's aperture to be set by the body, enabling shutter priority and program auto-exposure modes.
• The KAF-mount was Pentax's second attempt at adding autofocus to lenses and includes a small drive shaft to adjust the lens focus.
• The KAF2-mount is the same as the KAF-mount but adds two extra power contacts to transmit modulation transfer function (MTF) data.
• The KAF3-mount is used on Pentax lenses that solely rely on SDM or DC autofocus motors and is identical to the KAF2 mount but lacks the screw-drive autofocus drive shaft.

In addition to these exceptions and variations, it is important to note that different series of Pentax K-mount lenses have different features and are compatible with specific camera models. The currently produced series include the DA (digital), DA L (cheap digital kit), D FA (full-frame, digital optimized), and FA (full-frame) series.

Pentax M42 Screw-mount Lenses

The M42 screw mount is a standard for attaching lenses to 35 mm cameras, especially single-lens reflex models. The M42 mount was not developed by Pentax but the company did use it for some of its SLRs.

The M42 mount is also known as the Universal screw mount, as it was used by many manufacturers. The mount was first developed by Carl Zeiss in 1938 at the request of KW camera company for their Praktica line. The Praktica brand became well-known for the M42 mount, which is why it is also known as the Praktica thread mount.

The M42 mount is a metric screw thread of 42 mm diameter and 1 mm thread pitch. It is sometimes confused with the T-mount, which has the same throat diameter but a different thread pitch.

The M42 mount was further developed to include extra features. The pre-select type, for example, allowed the user to choose an aperture value without closing the aperture, and then quickly close it to the chosen value. This gave the benefit of comfortable framing and focusing with a bright viewfinder.

The last development of the M42 lenses was the introduction of a link between the camera and lens to transmit the lens aperture setting, allowing light metering with the aperture remaining wide open.

M42 mount cameras fell out of production in the late 1970s and early 1980s, with the exception of the Russian Zenit range. Pentax moved to the K mount in 1975.

However, due to the simplicity of the M42 lens mount and the large selection of lenses, M42 adapters exist for all current and many obsolete lens mounts. This means that M42 screw-mount lenses can be adapted to any Pentax DSLR, as well as SLRs made by other manufacturers such as Canon and Nikon.

Pentax M37 Screw-mount Lenses

The M37 screw-mount lenses were among Pentax's first SLR lenses, designed for Asahiflex SLRs. They feature a 37mm screw-in mount and have fixed focal lengths, manual focus, and diaphragm control.

To adapt M37 lenses to modern SLRs, you will need an M37 to M42 adapter, along with an M42 adapter for your specific camera mount. However, M37 to M42 adapters can be difficult to find.

M37 screw-mount lenses are not compatible with DSLR cameras without an adapter due to the shorter back focus, which would result in a loss of infinity focus.

Pentax K-mount lenses are compatible with all current Pentax DSLRs, although older lenses may have restrictions as not all exposure modes are supported.

Frequently asked questions