The 5 Best Pentax LX Lenses

By Nathaniel Stephan
Last Updated: April 9, 2020
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The Pentax LX is an excellent 35mm SLR. This article will cover the 5 best lenses for the Pentax LX, and also a few of substitute options.

In a rush? Here's the list of the 5 best lenses for the LX:

  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 categorized by kind of photography and price level. There are a number of choices to pick that have a wide range of prices suited to the price of the camera.

Standard Lenses

The following is a selection of 50mm focal lengths that are compatible with the LX. At the time when the camera was available for sale as new, there was frequently an offer available to buy a 50mm lens with the camera as a kit.

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

SMC Pentax-M 50mm f/1.7

  • "Kit" lens for the LX.
  • Great value.
  • Light, small, and compact.
  • 49mm filter threads.

Also found at: eBay, KEH, Adorama

If you do not already own it, the ideal initial lens to get a hold of is the SMC Pentax-M 50mm f/1.7. The 50mm f1.7 is widely available, is light, has very good image quality, is cheap, and streamlined. It is the most widely used lens on the camera.

The next version, the SMC Pentax-A 50mm f/1.7, is also a good choice.

SMC Pentax-M 50mm f/1.4

  • Exceptional optics.
  • Optical multi-coatings to improve performance.
  • Easy to find.
  • Comparatively affordable.

Also found at: eBay, KEH, Adorama

At the additional burden of size and weight, the SMC Pentax-M 50mm f/1.4 is just about a stop faster than the f/1.7. Expect to pay more than you would for an f/1.7 or f/2 lens. The subsequent version, the SMC Pentax-A, and earlier version, SMC Pentax, are both compatible with the LX.

SMC Pentax 50mm f/1.2

Similar to competing camera brands, Pentax made a fast 50mm lens. The resulting SMC Pentax 50mm f/1.2 is a high-priced, fast, and huge piece of glass.

The lens can be difficult to find since it can be used on Pentax DSLRs so the desirability extends beyond usage with 35mm film cameras. If you want to locate a copy you may need to check and have a look at what is available for purchase over weeks or months.

Find at: eBay or KEH


Below are just a few other good lenses that are comparable alternatives. As well as 28mm or 35mm focal lengths.

SMC Pentax 50mm f/1.2AmazoneBayKEHAdorama
SMC Pentax 50mm f/2AmazoneBayKEHAdorama
SMC Pentax-M 28mm f/2.8AmazoneBayKEHAdorama
SMC Pentax 35mm f/3.5AmazoneBayKEHAdorama

Wide Angle Lenses

SMC Pentax-M 28mm f/2.8

  • Great combination with a 50mm lens.
  • Super Multi Coating (SMC) to improve output.
  • Many copies are available.
  • Relatively low cost.

Also found at: eBay, KEH, Adorama

Not the best option, the SMC Pentax-M 28mm f/2.8, is still a good choice. The truth is, many do not actually consider it a wide angle lens. However, it is substantially less expensive than any wider option.

There's an abundance of wider focal lengths to select from, but they're possibly significantly more expensive or third-party options have obvious barrel distortion. Also, it is easy to see chromatic aberrations and other optical defects in third-party lenses.

More Alternatives

The general relationship for pricing is easy to understand. The wider the field of view, the more expensive the lens will likely be. Lenses with large apertures will also have higher prices.

Be aware that vintage wide angle lenses don't incorporate corrections that modern wide angle lenses have. The issue you are most likely to see with vintage wide angles will be obvious barrel distortion.

SMC Pentax-M 20mm f/4AmazoneBayKEHAdorama
SMC Pentax-M 28mm f/2AmazoneBayKEHAdorama
SMC Pentax 18mm f/3.5AmazoneBayKEHAdorama
SMC Pentax 24mm f/2.8AmazoneBayKEHAdorama

Portrait & Telephoto Lenses

SMC Pentax 135mm f/2.5

  • 85mm substitute.
  • Excellent value.
  • Relatively inexpensive.
  • Widely available.

Also found at: eBay, KEH, Adorama

The 85mm focal length wasn't as frequently used as they are today compared to when the LX was first released in 1980. 100mm or 135mm focal lengths were more widely used due to their lower cost.

You can see the price difference when checking what's available.

More Options

There are many telephoto lenses to select from. 85mm and focal lengths longer than 135mm are going to be higher priced.

SMC Pentax 85mm f/1.8AmazoneBayKEHAdorama
SMC Pentax 85mm f/2.2 SoftAmazoneBayKEHAdorama
SMC Pentax 105mm f/2.8AmazoneBayKEHAdorama
SMC Pentax 120mm f/2.8AmazoneBayKEHAdorama

Zoom Lenses

Prior to the introduction of autofocus, in the 1980s, there were a small number of lenses manufactured by third-party brands that performed better than Pentax's offering.

Many of the best performers were released with the Vivitar brand. Any zoom lens with the Vivitar Series 1 branding is going to have the best optics you can expect to see from a vintage zoom.

Sadly, finding copies of these lenses in usable condition can be rather challenging. Beyond that, no older zoom offers noteworthy performance. If you find one available for purchase that is cheap enough, it could be worth picking up.

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

  • Covers a popular zoom range.
  • Great for wildlife or portrait photography.
  • A rare time when a third-party lens is the best choice.

Also found at: eBay and KEH

More Alternatives

Here are some more options that you can look at if you want a zoom for your LX. None of them are going to be spectacular, and you would likely be better off buying a couple of Prime lenses.

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

Macro Lenses

Macro lens options for the Pentax LX suffer from supply problems. The available supply of Pentax K mount choices is small, which pushes prices higher than you’d pay for similar Nikon F mount or Canon FD mount lenses.

SMC Pentax 100mm f/4 Macro

  • Ideal focal length for 1x magnification.
  • Widely available.
  • Mediocre value.

Also found at: eBay, KEH, Adorama

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

Vivitar 55mm f/2.8 Macro

Vivitar 55mm f/2.8 Macro Lens manufactured by Komine
  • 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.

Also found at: KEH and Adorama

My favorite vintage macro lens I have owned, the 90mm Vivitar, was manufactured with a variety of camera mounts. However, it will be challenging to find a copy with a Pentax K mount.

The Vivitar 55mm is my second favorite vintage macro lens. Take into account that it does have a shorter working distance compared to the 90mm. It is excellent for table top and close-up photography, but it is not the best choice if you would like to capture macro photos at 1x magnification.

Both Vivitar macros were built by Komine and were released under various brand names. If you decide to look for a copy also search under the Panagor, Elicar, Quantaray, Spiratone, and Rokunar brand names.

There is a Vivitar 90mm Macro Review and a Vivitar 55mm Macro Review.

For taking photographs at life-sized magnification, 90mm-105mm focal lengths are going to be the most desirable choice. You will have enough working distance to allow the use of flash, while staying away from excessive weight and increased costs that longer focal lengths have.

More Alternatives

SMC Pentax-M 50mm f/4 MacroAmazoneBayKEHAdorama
Lester A Dine 105mm f/2.8AmazoneBayKEHAdorama

Used Pentax Lenses

Prices change all the time depending on demand and supply in manual focus glass. During the last several years, film photography has expanded in popularity, which has caused prices to rise.

Additional pricing pressure comes from Pentax DSLR users purchasing and collecting lenses. Third party manufactures tend not to make lenses for the K-mount, unlike the Nikon F or Canon EF mounts.

Marketing conditions are constantly changing, and sudden events can lead to large price movements. However, the price differences between options should stay similar.

Checking out a couple of websites is a sensible way to get reliable pricing. If you're fortunate enough to come across a terrific deal, get it since the best deals tend not to last long.

What Lens Mount Does the Pentax LX Use?

The Pentax LX has a Pentax K lens mount.

Introduced 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 time improvements have been made to add CPU contacts, electronically controlled apertures, autofocus, and metering information.

As long as a lens has a physical aperture ring, it will be compatible with Pentax film cameras. Having said that, it isn't a smart idea to waste money on pricey features that are not going to be able to be used by the camera. The exception would be if you also own Pentax DSLRs.

It is also possible to use the previous M42 lenses by using an adapter. The M42 Takumar lenses are the best to use in this situation. Even so, I wouldn't encourage doing this as getting them with focus rings that are not tight can be tricky.

Standard Lens Cap Size

The standard lens cap and filter ring thread diameter used on most manual focus Pentax K mount lenses is 49mm. Lenses were sold with slip-on caps, and not the more typically used center-pinch design today. Looking around at what is available, you will find a lack of original caps being sold with lenses.

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

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

Pentax-M vs Pentax-A

SMC Pentax and Pentax-M lenses have a stop-down coupler that allows the camera to have a mechanical linkage to the lens. The stop-down coupler makes it possible for the camera to know what the aperture is set to so that the light meter will meter correctly without being required to use stop-down metering.

The Pentax-A series added the feature for the camera to set the aperture in the lens. This means that cameras that are compatible with the Pentax-A changes have the capability to do aperture priority and shutter priority modes.

However, due to the fact that that capability is not compatible with the camera, it does not make financial sense to spend money on features that the camera cannot use.

Related Posts

That's it for info on the best lenses for the LX. Here's further info that will provide you with more info about the camera can be found listed below:

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