A first impressions review of the Pentax K-3 Mark III Monochrome

Introduction

Despite this being my 279th piece of writing, this is my first time writing on a Pentax camera, with the only other Pentax camera I have shot with before the Pentax Q, an innovative camera probably too ahead of its time.

Many thanks to a dear friend, Sam, who gamely lent me his personal Pentax K-3 Mark III Monochrome for a short morning photo-walk. This ‘first impressions’ review will not cover the camera in depth as I simply do not have access to this camera for a reasonable length of time and I will touch on image output, how my post-processed files compare against the straight-out-of-camera (SOOC) results, along with some broad impressions of the Pentax K-3 Mark III Monochrome paired with the SMC Pentax-FA 28–70mm ƒ2.8 AL.

*The SMC Pentax-FA 28-70mm ƒ2.8 AL lens was discontinued in 2004.
*Ricoh-Pentax Singapore does not make the Pentax K-3 Mark III Monochrome available for the local market, the set used for this article was sourced from eBay.

Some musings to begin

For those of us who believe photography is a soul-searching act, the journey towards black and white is often a pilgrimage. We start by stripping the colour from our digital files in post-processing, thinking we can achieve the necessary depths of tonality. We eventually learn, however, that the black and white image, in its most essential form, is not merely the absence of colour, but the relentless, beautiful interplay of light and shadow in telling a story.

Leica (my M11 Monochrom review linked) has long championed this purity with their Monochrom line since 2012 which was already a niche market, and to my surprise Pentax stepped forward with a declaration of the K-3 Mark III Monochrome in 2022, an APS-C sensor DSLR camera with a colour-filter array-less approach.

The Leica Monochrom cameras are already niche, and Pentax has doubled down on a niche within a niche by producing a pure black and white APS-C sensor DSLR camera.

In an industry obsessed with speed, video, and mirrorless technology, Pentax has made a bold, almost contrarian move and let’s take a closer look.

tl:dr

The Pentax K-3 Mark III Monochrome is a niche with a niche, a monochromatic APS-C DSLR camera. While it may lack the philosophical heft and the premium price tag of its German counterparts, this camera compensates with a level of rugged practicality that hawks back to the time when DSLRs reigned, with excellent ergonomics and an unmatched value proposition.

The dedicated monochrome sensor delivers a dynamic tonal range and high-ISO performance that validates the colour-filter-array-less approach. For those who yearn for the purity of monochrome image-making but operate on a realistic budget, this camera is a going to be an option.

My money is on that the 2026 incoming GR IV Monochrome will spot the same sensor from the Pentax K-3 Mark III Monochrome. Hence for those who are keen for a wallet-friendlier fixed lens option, the few months wait is hopefully going to be worth it.

For those seeking a Leica Monochrom vs Pentax Monochrome comparison, it is not much a fight with the former being full frame, sporting better glass (generally) and this shows in the output including wider dynamic range from the former.

Technicalities (the full details are here for the spec reader)

• Monochrome CMOS, APS-C (23.3 × 15.5mm) sensor at 25.73 megapixels (effective)
• Pentax KAF2 mount, compatible with KAF4, KAF3, KAF2 (power zoom compatible), KAF, KA lenses.
• Stabilisation: 5-axis in-body SR II (sensor-shift)
• Pentaprism Viewfinder with approximately 100% coverage, 1.05× magnification
• 101 autofocus points (25 cross type), phase-matching autofocus.
• ISO from 200 to 1,600,000
• Burst: up to 12 fps (with buffer figures depending on RAW/JPEG settings)
• Shutter: Mechanical 1/8000–30s; Electronic 1/16000–30s
• Video: 4K (30p/24p), Full HD up to 60p
• Storage: Dual SD slots (UHS-II supported in SD1 slot)
• Approximately 820 grams with battery and SD-cards, 134.5mm x103.5mm (H) x 73.5mm (D) 
• Monochrome “Custom Image” modes: Standard / Hard / Soft, with further customisation options.

Build and Handling

Most of us had a phase where the DSLR was our tool of choice, and in this respect, the Pentax K-3 Mark III Monochrome evokes this sense of familiarity I had with the Nikon Df and D850 DSLR cameras. To use the word ‘robust’ to describe the build would be lacking and ‘rugged’ will probably be more appropriate.

The Pentax K-3 Mark III Monochrome at 820 grams is still quite a reasonable weight though the lightest DSLR bodies like Canon 250D were around a lightweight 449 grams.

for obvious reasons, I did not include Full frame DSLRs in this comparison

Picking up the K-3 Mark III Monochrome, I was instantly reminded that this is a camera built for work, a camera that you will be blowing off the dust instead of kneeling down in tears while picking up pieces of it if you ever drop the camera. One of the most lovely feature is the deep and well-shaped right-hand grip and exceptional ergonomics, making this camera a tool you can hold for hours without fatigue.

In a world dominated by electronic viewfinders, the large, crystal-clear optical Pentaprism Viewfinder is a refreshing return to the essential. It offers a 100% field of view with an impressive 1.05x magnification, giving you an unpowered, direct connection to your scene. Unlike the EVF, which shows you the processed WYSIWYG image, the OVF shows you reality, forcing you to pre-visualise the black and white result: a crucial step in developing the monochrome mindset.

A minor lament is the fixed 3.2 inches 1.62 million dots rear screen as an articulated screen would have been a practical concession for weird angled compositions. However, I do appreciate the abundance of tactile dials and buttons which means you rarely need to delve into the menus, maintaining the mechanical focus of the shooting process.

Menu system wise I will not able to touch on much as with me being new to Pentax, I had Sam set up the camera to my preferences and I shot in Aperture-priority, which was logical to work with and not a big issue in my time with the camera.

Performance

Auto-focus was generally snappy and quite reliable, despite that I was working with a much older already discontinued twenty years old lens. A pleasant surprise to be honest, and a comparable autofocus experience will probably the Fujifilm X100V.

Being an DSLR, of course the camera viewfinder does not come with the modern conveniences like face/eye detection boxes, Sony-level tracking squares but then it is what is it, a crystal clear optical viewfinder giving almost a 100% view of the scene.

I will share two sets of samples below, one post-processed to my preference and the other the original JPEG straight out of camera.

One of the gains of using a Monochromatic sensor is the added malleability of post-processing one can do.

The Pentax K-3 Mark III Monochrome also provides a range of digital filters, comprising Grainy Monochrome, Tone Expansion, Invert Color, Shading, High Contrast, Retro and Toy Camera. Custom Image offers Standard, Hard and Soft options. Not something I personally will use, but good to have when the creative / exploration streak hits.

As expected, the usable ISO range is extraordinary compared to a color-able sensor, starting from ISO 200 and stretching all the way to ISO 1 600 000. In practice, files are essentially noise-free from ISO 200 through ISO 800, with only the most fussy eyes spotting faint noise (let’s call it noise and not grain) beginning to appear at ISO 1600 and ISO 3200. Even at ISO 6 400, the images are quite clean from noise and usable, though probably the highest ISO for images that will be scrutinised closely.

At and beyond ISO 12 800, noise becomes more apparent, but the image stays well-defined, and this holds up through ISO 51 200 for the more forgiving photographers. Beyond ISO102 400, contrast starts to breaks down and personally I will not use any files shot beyond ISO 204 800.

Conclusions

The Pentax K-3 Mark III Monochrome occupies a truly unique space in the photographic ecosystem where fortunately or unfortunately comparisons are hard to find. It takes the philosophical purity pioneered by Leica and places it within a highly practical, weather-sealed, image-stabilized DSLR body for a fraction of the price of the Leica Monochrom cameras.

This camera is for the photographer who is serious about black and white, but needs the robustness and flexibility of a modern system. Like the Leica Monochrom cameras, the Pentax K-3 Mark III Monochrome removes the distraction of colour and replaces it with an immense tonal canvas. While I do fnd the straight-out-of-camera JPEGs ‘flat’ to my preferences, the flexibility offered by the PEF RAW files is simply magnificent, allowing the photographer to pull stunning detail and contrast into the final image.

The decision to commit to this body is not about function. It is, in fact, less versatile than its colour-capable sibling; but about intentionality. It is about elevating monochrome from a post-processing afterthought to a deliberate, initial act of vision.

Considering its highly competitive price point against the alternatives, the Pentax K-3 Mark III Monochrome is more than just a camera; it is a gateway to black and white photography for the ones really serious about this genre.

I personally applaud Pentax for making a true black-and-white sensor more accessible to a wider circle of dedicated photographers. And while I can understand why some retailers in certain countries choose not to bring this camera into their local markets, it’s undeniably a pity because in the medium to long run, the brand risks missing an opportunity to encourage, nurture, and grow its user community.

Thank you for reading.

Disclaimers:

1. All product photos and samples here were photographed by me. I believe any reviewer with pride should produce their own product photos. 

2. All images were shot with the Pentax K-3 Mark III Monochrome with Pentax-FA 28-70mm ƒ2.8 AL, both on loan and returned from a dear friend.

3. This review is not sponsored.

4. I write as a passion and a hobby, and I appreciate that photography brands are kind enough to respect and work with me.

5. The best way to support me is to share the review, or you can always help support me by contributing to my fees to WordPress for the domain using the Paypal button at the bottom of the page.