Asahi Pentax MX Film Camera Review

Asahi Pentax MX is a compact mechanical SLR compatible with a vast array of affordable lenses. It’s small enough to fit in a pocket (with the right lens), and it’s built like a tank.

If you’ve shot with the Olympus OM-1, you’ll love the Pentax MX. It’s extremely utilitarian — nothing extra — small and also light. Plus: an all-metal body construction at a very competitive price.

Pentax MX is a popular camera with many positive reviews. But no camera is perfect, and so the MX has a few things you should know. In this review, I’ll cover the basics and known issues.

I’ll also suggest a few compact mechanical SLR alternatives, should you like a faster shutter, an even more minimalist design, or a smaller profile (yes, that exists¹).In this review: Technical specifications. Design and ergonomics. Build quality and known issues. Pentax K-Mount lenses. Pentax MX alternatives. How much does the Pentax MX cost, and where to find one. Support this blog & get premium features with GOLD memberships!¹ — On a half-frame camera.

Technical specifications.

Size, weight, all-metal construction, an all-mechanical shutter, and a minimalist feature set define Pentax MX. This camera was in production for nine years, from 1976 to 1985.

Lenses: Accepts all K-Mount lenses (except the newer FA-J and DA lenses without aperture rings). Kit lens is SMC Pentax-M 1:1.7 50mm.

Focusing: Single-lens reflex (SLR) with an interchangeable focusing screen, 0.97x magnification and 95% coverage. A very comfortable finder for a camera of this size that covers only a tiny sliver of the edges of the actual frame. DOF preview lever and 4-12 second self-timer operated via lever on the front plate.

Shutter: Focal-plane, 1s – 1/1000s + bulb. Shutter speeds are indicated in the viewfinder in small black type on the right.

Metering: Center-weighted uncoupled through-the-lens type, EV 1-19. Works with film ISO range of 26-1600 (no compensation). Shows exposure hints in the viewfinder with an array of green, yellow, and red LEDs.

Battery: Optional (only for the uncoupled meter operation), 2 × LR44.

Flash: FP and X sockets, hotshoe. Sync speed: 1/60s.

Chassis: Painted brass. 135.5mm × 82.5mm × 49.5mm (5⅓” × 3¼ × 2”), 495g / 17.5oz.

Design and ergonomics.

Pentax MX is one of the few SLRs that could reasonably fit in a pocket. It would have to be a jacket or a coat, but it can slide into one if you mount the 40mm Pentax-M 1:2.8 that protrudes just over 2cm/⅘” from the mount.

The camera is not so light that you won’t notice it. After all, its chassis is made of brass. Yet it’s much lighter than most SLRs of that period and even many modern plasticky DSLRs.

The MX feels very solid in the hand. Everything fits perfectly, and the finishing job on the camera is top-notch. Sure, the design could be polished even further to match the obsessive investment into feel and appearance of a Leica or a Voigtländer Vitessa A rangefinder — but that’s not what this camera is made for.

Pentax MX was designed to be a high-quality working camera, which it absolutely is. However, being this small, this all-mechanical system can be difficult to fix should it have any issues.

In the field, it’s a nimble shooter. Despite being a fully manual camera (with exposure assist), I could operate my Pentax MX with just one hand. It has a decent grip, even though its body design is rather blocky. With a small lens, you could focus, adjust the aperture, and change the shutter speed without involving your left hand at all. Both the aperture and shutter speed will be indicated inside the viewfinder; thus, you don’t even need to put the camera down between exposures.

Please note, however, that shooting with just the right hand is possible but not necessarily comfortable or easy with this camera. Also, the shutter speed display in the viewfinder won’t be visible without a good amount of light, as it’s a black typeface on a transparent material. Same with the apertures, which are projected into the viewfinder directly from the top of the lens.

The viewfinder on the Pentax MX is fairly bright — brighter than on the Olympus OM-1 (its main competitor) — but not as clear, large, and precise as the DP-1 on a Nikon F2. The 95% coverage means that a tiny sliver of the actual film frame that will be exposed is cut off, though that has never been an issue. It has a decent eye relief distance and is pretty easy to use with glasses.

The depth-of-field preview on Pentax MX is a “hidden” feature that you activate by pushing the self-timer lever on the front plate towards the lens.

The shutter button on the MX is well-designed, though inconspicious-looking. It has a bit of a travel distance, but it is easy to press, feel, and use without adding any camera shake, which is important for taking sharp photos! The shutter button is lockable; a half-press will activate the light meter. Right next to the shutter button is a tiny window that will turn orange when the frame is wound and ready.

The light meter will stay on if the film advance lever is pried open slightly until it clicks and stays in position. The meter is uncoupled, meaning that it’ll indicate a correct exposure but won’t actually touch the controls. It works by lighting up five tiny bulbs inside the viewfinder on the right. The middle green bulb indicates a correct exposure; an orange bulb above or below indicates that the exposure should be adjusted up or down by one stop. The remaining red bulbs above and below the rest indicate 2+ stops of over- or underexposure.

Center-weighted metering means the camera prioritizes exposure for areas in the middle of the frame, while still accounting for light values in the fringes. While reasonably accurate, the exposure indicator bulbs are extremely sensitive and tend to jump up and down rapidly in high-contrast scenes. This can be distracting and confusing at times, which is why I often preferred to rely on my Sunny 16 knowledge in the field.

The ISO settings for the meter are controlled by pushing a small metal button on top of the shutter dial and rotating it.

Loading the Pentax MX for the first time may feel a little confusing for some. Instead of a typical film catch, it uses a white plastic drum with slits where you’d stick the leader directly and begin advancing from there. Everything else is standard.

While there isn’t a world of accessories for the MX, as some other cameras may boast, it accepts all the standard ones, like a hotshoe flash and a tripod socket, plus extras like a motorized film winder and custom screens.

Build quality and known issues.

Pentax MX is a well-built camera. It’s very solid, uses quality materials and is generally very dependable. Design-wise, there isn’t much that could be improved other than replacing a few plastic parts, like the spacer under the hotshoe, with fancier materials. And, like I said earlier, the MX is not a jeweller’s camera, it’s a working tool.

A common issue with these cameras is a stuck return mirror. Essentially, after taking a shot, the viewfinder may remain black, even if you wind to the next frame.

A stuck return mirror is usually a lubrication issue that may improve after some use (see “exercising your gear”); however, in many cases, that won’t help on this camera. The issue lies deep within the complex mechanical system, which can take a long time to locate and remedy, even for an experienced technician.

My camera has this issue. All the online info pointing to several components below the bottom plate is, unfortunately, useless. A proper fix would require reaching the mirror box assembly.

A temporary solution is to avoid winding the film onto the next frame until you’re ready to take a photo. The stickiness exacerbates when the camera is wound and left in that position for longer than a few minutes or hours.

Pentax K-Mount lenses.

Pentax K-Mount offers a wide range of lens options, from the standard 50mm types, like the SMC Pentax-M 1:1.7 50mm, to more specialized glass, like the SMC Pentax-M 100mm 1:4 Macro, some of the thinnest SLR pancake lenses, like the SMC Pentax-M 40mm 1:2.8, and a whole range of other options, including the L39, M39, and M42 with adapters.

I’ve tried a few. As with most systems that support such a wide variety of lenses, there are different levels of quality. Even the Pentax-branded lenses are not all the same. Whereas the 1.7 that came with the camera felt great all around, the version that came with my Pentax K-1000 lacked in quality.

I absolutely recommend doing some research before buying glass for this camera, though it’s also fair to say that many lenses for this camera are very good; the main thing to watch for is the build quality and materials, not the optics, as those rarely disappoint, especially if they’re from Pentax.

Pentax MX alternatives.

The Olympus OM-1 is an obvious replacement contender as it’s even more minimalist (a match-needle meter instead of diodes and a simpler, more reliable shutter mechanism). Though I don’t think the OM-mount has a pancake lens quite as flat as the SMC Pentax-M 40mm 1:2.8.

The Olympus PEN FV with the 1:2.8 E.Zuiko Auto-S make the most compact, lightest all-metal mechanical SLR possible — and no prism bump! The only downside for you may be that this is a half-frame system, but it has an impressive selection of lenses and features an outstanding design. Also note that this camera’s top shutter speed is 1/500s.

The Nikon FM2/FM2n is one of the nicest mechanical cameras Nikon has ever created. Its titanium shutter curtain tops at an incredible 1/4000s. Just like the rest of the cameras on this list, its chassis is all-metal, though I would argue it’s a little better designed and built than the rest. Unfortunately, Nikon does not make pancake lenses; the smallest would be the AI-S Nikkor 50mm 1:1.8 or the Nikon E 50mm 1:1.8.

How much does the Pentax MX cost, and where to find one.

Pentax MX cameras sell for $150-250 in late 2025, depending on condition and seller. The cheapest copy isn’t always the best option, especially considering the difficult-to-fix shutter issue I mentioned above.

Check out The Vintage Film Camera Buying Guide for more info if you’re new to buying vintage cameras.

❤ By the way: Please consider making your Asahi Pentax MX Film Camera purchase using this link so that this website may get a small percentage of that sale — at no extra charge for you — thanks!