5 Great Pentax KX Lenses

´╗┐The Pentax KX is a great 35mm film SLR. This page is going to talk about the 5 best lenses for the Pentax KX, as well as a handful of alternative options.

In a rush? The following is the list of the best lenses for the KX:

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  1. Kit Lens - SMC Pentax-M 50mm f/1.7
  2. Wide Angle Lens - SMC Pentax-M 28mm f/2.8
  3. Portrait Lens - SMC Pentax 135mm f/2.5
  4. Zoom Lens - Vivitar Series 1 28-90mm f/2.8-3.5
  5. Macro Lens - SMC Pentax 100mm f/4 Macro

The best Pentax K mount lenses are grouped by pricing and kind of photography. There are many suggested alternatives to select from that are in price ranges ideal for the value of the camera.

The following is a selection of 50mm focal lengths that are compatible with the KX. When the camera was being sold as new, there was quite often an offer bundling a 50mm lens as kit for a reduced price.

They are considered standard lenses due to the fact that the angle of view is close to what people see with their eyes.

SMC Pentax-M 50mm f/1.7 Standard Prime Lens
SMC Pentax-M 50mm f/1.7
  • “Kit” lens for the KX.
  • Fantastic value.
  • Light, small, and compact.
  • 49mm filter threads.

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If it did not come with the camera, a great initial lens to get a hold of for the KX is the SMC Pentax-M 50mm f/1.7. The 50mm f1.7 is easy to find, is cheap, has terrific photo quality, light, and streamlined . This is the most used lens on the camera.

{You can also purchase the second version, the SMC Pentax-A 50mm f/1.7|The next version, the SMC Pentax-A 50mm f/1.7, is also a good choice}.

SMC Pentax-M 50mm f/1.4 Fast Prime Lens
SMC Pentax-M 50mm f/1.4
  • Exceptional optics.
  • Improved output because of optical multi-coatings.
  • Easy to find.
  • Comparatively low-priced.

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At the increased burden of size and weight, the SMC Pentax-M 50mm f/1.4 is just about a stop faster compared to the f/1.7. An f/1.7 or f/2 lens will cost more. The earlier version, SMC Pentax, and later version, SMC Pentax-A, are both compatible with the KX.

SMC Pentax 50mm f/1.2
SMC Pentax 50mm f/1.2

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Similar to competing camera companies, Pentax created a very fast 50mm lens. The resulting SMC Pentax 50mm f/1.2 is a very large, fast, and pricey piece of glass.

The lens can be difficult to come across since it will work on Pentax DSLRs so the appeal extends beyond use with 35mm film cameras. If you want to find one you might need to check and see what’s offered over weeks or months.

SMC Pentax-M 28mm f/2.8 Prime Wide Angle Lens
SMC Pentax-M 28mm f/2.8
  • Great combination with a 50mm lens.
  • Super Multi Coating (SMC) to improve performance.
  • Many copies are available.
  • Relatively low-priced.

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The SMC Pentax-M 28mm f/2.8 isn’t the best option. The truth is, many people might not even consider it a wide angle lens. Nevertheless, it is considerably more affordable than any wider option.

There are plenty of wider focal lengths to consider, but they’re frequently much less affordable or third-party choices have noticeable amounts of barrel distortion. Also, it is easy to see optical defects like chromatic aberrations in third-party offerings.

The rule of thumb for prices is simple to understand. The wider the field of view, the more expensive the lens is going to be. Fast lenses will also be more expensive.

Take into account, that these do not include corrections that modern wide angle lenses have. The issue you’re most likely to see with vintage wide angles will be obvious barrel distortion.

  • SMC Pentax-M 20mm f/4
  • SMC Pentax-M 28mm f/2
  • SMC Pentax 18mm f/3.5
  • SMC Pentax 24mm f/2.8
SMC Pentax 135mm f/2.5 Telephoto Prime Portrait Lens
SMC Pentax 135mm f/2.5
  • 85mm substitute.
  • Excellent value.
  • Relatively inexpensive.
  • Widely available.

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85mm focal length lenses were not as commonly used as they are today compared to when the KX was initially released in 1975. As a result of being more affordable, 100mm and 135mm focal lengths were more widely used.

You can see the price difference when you view available listings online.

There are plently of telephoto lenses to select from. 85mm and focal lengths longer than 135mm are going to be expensive.

  • SMC Pentax 85mm f/1.8
  • SMC Pentax 85mm f/2.2 Soft
  • SMC Pentax 105mm f/2.8
  • SMC Pentax 120mm f/2.8

Before the release of autofocus, in the 1980s, there were a small number of lenses manufactured by third-party companies that performed better than what Pentax was offering.

Many of the best performers were released with the Vivitar brand name. Zooms that’s got the Vivitar Series 1 branding is going to have the best optics you can expect to see from an older zoom.

Unfortunately, getting one of these lenses in usable condition can be rather challenging. Keep in mind, no vintage zooms offer noteworthy performance. If you find a copy available for purchase that is cheap enough, it could be worth buying.

Vivitar Series 1 28-90mm f/2.8-3.5 Zoom Lens
Vivitar Series 1 28-90mm f/2.8-3.5

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Here are some more options that you can check out if you need a zoom lens for your KX. None of them are going to be amazing, and you’d likely be better off acquiring a couple of prime lenses instead.

  • SMC Pentax 85-210mm f/3.5
  • Vivitar Series 1 70-210mm f/3.5
  • SMC Pentax 45-125mm f/4

Macro lens options for the Pentax KX suffer from supply problems. The available supply of Pentax K mount options is small, which increases prices higher than you’ll pay for comparable Nikon F mount or Canon FD mount lenses.

SMC Pentax 100mm f/4 Macro Lens
SMC Pentax 100mm f/4 Macro
  • Ideal focal length for 1x magnification.
  • Widely available.
  • Mediocre value.

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A small number of people online have experienced balsam separation of the front doublet. This is worrying because even a little bit of separation will spread gradually and eventually make it unusable. If you see any signs of balsam separation, avoid that copy and keep looking.

Vivitar 55mm f/2.8 Macro Lens
Vivitar 55mm f/2.8 Macro
  • The second best vintage macro lens I’ve used.
  • An outstanding lens for close-up photography.
  • Can achieve life-size magnification without needing an extension tube.

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The best vintange macro lens I’ve used, the 90mm Vivitar, was produced for a variety of camera mounts. However, it’s difficult to find a copy that features a Pentax K mount.

The Vivitar 55mm is my second favorite vintange macro. Keep in mind that it does have a smaller working distance when compared to the 90mm. It is a good choice for table top and close-up photography, but it is not the best choice if you want to capture macro images at 1x magnification.

Both Vivitar macros were produced by Komine and were sold under several brand names. If you search for a copy also look under the Panagor, Elicar, Quantaray, Spiratone, and Rokunar brand names.

There is a Vivitar 90mm Macro Review and a [/vivitar-55mm-f-2-8-macro-lens-review](Vivitar 55mm Macro Review).

For capturing photographs at macro magnification (1x), 90mm-105mm focal lengths will be the ideal option. You’ll have a big enough working distance to allow the use of flash, while avoiding excessive weight and excessive costs that come with longer focal lengths.

Interest and supply will determine the cost of vintage lenses. During the past few years, film photography has grown in popularity, which has caused prices to go up.

More pricing pressure stems from Pentax DSLR users collecting and buying lenses. Third party companies tend not to manufacture anything for the K-mount, unlike the Canon EF or Nikon F lens mounts.

Economic circumstances are constantly changing, and unforeseen events can quickly lead to price movements. Even so, the relative prices between choices should stay similar.

Checking a couple of sites is a smart way to get accurate prices. If you’re lucky enough to discover an excellent deal, buy it because the best deals tend not to last very long.

The Pentax KX uses the Pentax K lens mount.

Released in 1975, the Pentax K mount is still used in cameras. It replaced the M42 screw mount that was used in previous cameras such as the Asahi Pentax Spotmatic. Over the years alterations have been made to add electronically controlled apertures, CPU contacts, autofocus, and metering information.

As long as a lens has a physical aperture ring, it will be backward compatible with Pentax film cameras. Keep in mind, it isn’t a smart idea to waste money on expensive features that can not be useable. An exception would be if you also own Pentax DSLRs.

It’s also possible to use the previous M42 mount lenses by using an adapter. The older Takumar lenses would be the best to use. Having said that, I wouldn’t encourage doing this as finding them with focus rings that aren’t tight can be tricky.

The standard lens cap and filter ring thread diameter used on the majority vintage manual focus Pentax K mount lenses is 49mm. Lenses were sold with slip on caps, not the more prevalent center-pinch kind found today. If you look around, you will find a lack of original lens caps sold with the lenses.

Bear in mind large front elements will need bigger caps and filters.

The advantage of having a standardized thread size is that you only need to own only one filter set.

SMC Pentax and Pentax-M lenses have a a stop-down coupler that allows the camera to have a mechanical linkage to the lens. The stop-down coupler will allow the camera to know the aperture is set to so that the light meter is able to meter accurately without being required to use stop-down metering.

The Pentax-A series added the feature for the aperture in the lens to be set by the camera. Cameras that support the Pentax-A changes have the capability to do shutter priority and aperture priority modes.

However, since that feature isn’t supported by the camera, it would not make sense to spend money on capabilities that the camera is not able to use.

That is it for info on the best lenses for the KX. Here’s additional information that will give you more information about the camera can be found below: