Pentax Center Pinched Camera Lens Cap

One Cap to Rule Them All: The K-Mount (and Universal) Secret

The beauty of Pentax is the K-mount—a standard that has connected generations of lenses. While the mount is consistent, front filter threads vary. That’s where the universal key comes in: the filter thread diameter.

Look at the front rim of any of your lenses. Find the Ø symbol followed by a number (like Ø49mm or Ø58mm). That’s your size. This simple millimeter measurement is what makes these caps perfectly compatible with your entire collection and beyond.

Here’s the crucial point: While branded for Pentax, these caps adhere to the global thread standard. A 52mm cap fits any 52mm thread, whether it’s on a Pentax, Takumar, Sigma, or any other brand’s lens. This makes them the ideal, versatile solution for Pentaxians who are masters of adaptation.

Your Pentax Lens Cap Quick-Reference Guide

To simplify your search, here’s a breakdown of which cap fits common Pentax lens types and series. This is a helpful guide, but always trust the Ø number on your specific lens as the final answer.

Straight Talk for Pentax Shooters: Your Questions Answered

• “My vintage Pentax or Takumar lens has a built-in, slide-out lens hood. What gives?”
  You’ve hit on a classic feature! Many legendary manual focus lenses have integrated, slide-out hoods. For these, you typically cannot use a standard pinch cap. The lens was designed to use its own dedicated, often slip-on, front lens cap that fits over the extended hood. Always try to find the original style cap for these gems to preserve their look and function. Our pinch caps are for lenses with standard filter threads.

• “I use UV filters on all my lenses for extra protection, especially with Pentax’s weather-sealed bodies. Does the cap still fit?”
  Yes, absolutely. This is a best-practice setup. The cap is designed to fit over any screw-in filter. For maximum protection, combine a high-quality weather-resistant filter with our cap. The filter provides a permanent seal against dust and moisture on your weather-resistant lenses, and the cap adds a physical barrier against impacts and scratches in the bag.

• “The original Pentax caps are great, but some of mine are lost or broken. Are these as good?”
  These are designed to be direct, high-quality replacements. They match the precision fit of the originals. The advantages are availability (easy to find the exact size) and consistency (having the same reliable cap on all your lenses). For many classic lenses where original caps are rare, this is the perfect practical solution.

• “I adapt old M42 screw-mount lenses to my K-mount camera. Will these caps fit those?”
  This is a huge benefit! Yes, they will. An M42 lens with a 49mm filter thread will work perfectly with the NP3438 (49mm) cap. Our universal thread-size caps are the ideal, clean-looking solution for your adapted lens collection, keeping everything uniform.

• “Any tips for handling caps with the often deep, petal-shaped hoods on DA lenses?”*
  The process is universal: Cap on the lens, hood over the cap for storage.

  1. For shooting: Remove cap, attach hood.

  2. For transport: Remove hood, put cap on lens, reverse the hood and mount it over the capped lens. This locks the assembly together and protects both the front element and the hood’s interior.

Shooting with Pentax is about connecting with photography’s craft and history. Your kit tells a story. Protecting it shouldn’t be complicated or require a pile of mismatched accessories.

The NP3438 series offers a straightforward, elegant solution: a small set of precisely sized caps that can protect virtually every lens in your arsenal, from the latest D FA glass to your most prized vintage find. It’s the simple, smart choice for the photographer who values substance over flash, and longevity over disposability.

Find your Ø. Secure your legacy. Keep shooting.