Metering the Mechanical: Review of the KEKS M-Meter on the Leica M4

Introduction

Some cameras charm because they do everything for you; others charm because they ask you to be more present and in control.

The Leica M4 belongs very much to the second group.

For many Leica users, the M4 sits in a rather special place. It retains the clean, mechanical simplicity of the earlier M bodies, yet feels more practical in daily use with its angled rewind crank, quick-load system, and direct rangefinder experience. It is one of those cameras which reminds one that photography does not always need more automation to feel more complete.

I chose the Leica M4 for a practical reason, the presence of 35mm frame-lines which the Leica M3 lacks.

But there is one very practical inconvenience: the Leica M4 has no built-in light meter.

Of course, this is part of its charm. One can photograph by Sunny 16, use a handheld meter or simply build exposure confidence over time (sacrificing some film in the process). However, in changing light, when photographing family, travel scenes, interiors, or street moments, having a meter available does make the experience more convenient.

The samples shared here were all metered using the KEKS M-meter on the Leica M4. I am sure we all agree the best way is to simply test it in real life.

The KEKS M-Meter is designed specifically for meter-less Leica M bodies and couples to the camera’s shutter speed dial in a way inspired by Leica’s original MR meter.

And that is where the KEKS M-Meter becomes interesting.

This is not merely another modern small digital meter just sitting on top of a film camera. Unlike the other light meters, it is a modernised, rechargeable, OLED-equipped light meter that tries to integrate itself into the operation of the Leica M4 rather than behave like a separate device attached as an afterthought.

For brevity’s sake, I will refer to the KEKS M-Meter simply as the M-Meter from this point onwards.

Let us take a deeper look.

tl:dr

The KEKS M-Meter is a shoe-mounted light meter made specifically for meter-less Leica M bodies such as the M3, M4 series, M-A and on. On the Leica M4, it gives a very practical modern convenience without changing the essential mechanical nature of the camera.

The main reason to consider the KEKS M-Meter is not simply accuracy. It is workflow.

Unlike most shoe-mounted meters, the M-Meter couples directly to the Leica M’s shutter speed dial. This means that when the M-meter is mounted, it reads your set shutter speed is directly without any need for further inputs. One then reads the suggested aperture from the OLED screen and sets the lens accordingly. In use, this feels much closer to using an integrated metering accessory than having to transfer values.

It offers single and continuous metering with a double tap to activate, shutter-priority operation, a 1.3-inch OLED display, USB-C charging, exposure compensation from -3 to +3 EV, selectable aperture and ISO steps, ISO 6–3200, and a 30-degree average metering angle.

One can set min/max aperture values to suit the lens being used, down to the duration of operation before the M-meter goes to sleep. For this review, I was using the Elmarit-M 28mm ƒ2.8 hence I had set the aperture range from ƒ2.8 to ƒ22.

While I appreciate the KEKS M-meter going from ƒ1 to ƒ128, I am very glad the meter allows me to set max/min aperture values to avoid wasting time with an unusable setting.

There are caveats of course, the top-plate display means one still has to look away from the viewfinder, and it remains an electronic accessory on an otherwise fully mechanical camera which might irk purists. The rechargeable battery is convenient, and it is always advisable to start a shoot with a full charge.

Still, on the Leica M4, the M-Meter makes a lot of sense.

It gives the camera just enough modern convenience without turning the M4 into something it was never meant to be, and in this sense, a tool that allows me to focus on framing and visualising the shot.

Technicalities

• Compatibility: Leica M1, M2, M3, M4, M4-2, M4-P, M-A, MD and MD-2
• Metering type: Ambient reflected light meter
• Metering angle: 30-degree average metering, approximately equivalent to a 50mm lens view
• Metering modes: Single metering and continuous metering
• Exposure mode: Shutter priority from 30 seconds to 1/1000s
• ISO range: ISO 6 to 3200
• EV range: EV 1 to 20
• Aperture range: f/1.0 to f/128
• Aperture steps: Full, half, or third stops, ISO steps: Full, half, or third stops
• Exposure compensation: -3 to +3 EV in 1/3-stop increments
• Display: 1.3-inch OLED
• Battery: Built-in rechargeable 240mAh battery, USB-C
• Battery life: Over 10 hours of use, with full charge in about 1 hour
• Finishes: Satin Chrome, Black Chrome, and Black Paint
• Materials: Aluminium for Satin Chrome and Black Chrome versions; brass for Black Paint version

Handling

The KEKS M-Meter changes the Leica M4 experience in a way that is subtle but meaningful.

A typical shoe-mounted light meter sits on the camera, takes a reading, and then leaves the photographer to transfer the settings manually. You read the suggested shutter speed and aperture, then adjust the camera accordingly. This works, of course, and there are many good meters that do exactly this.

The KEKS M-Meter works differently.

It physically couples to the Leica M4’s shutter speed dial. Once mounted, the meter’s control wheel and the camera’s shutter speed dial move together. This is the important part. You are no longer treating the meter and camera as two separate objects. You are effectively setting the camera’s shutter speed through the meter, while the meter calculates the corresponding aperture for the selected shutter speed.

This is why the M-Meter feels closer to a modern Leicameter than a generic digital shoe meter.

With the Leica M4, the operation is simple. Set the ISO for the roll of film. Point the camera at the subject you wish to meter. Press the rear button for a reading. Rotate the coupled dial until the displayed aperture suits your lens and intention. Then set that aperture on the lens.

And that’s it.

In practice, the KEKS M-Meter does not make the Leica M4 “automatic”. It simply removes one layer of friction during use.

This matters because the M4’s appeal is its rhythm. Wind, frame, focus, expose, release. A meter that interrupts that rhythm too much will eventually stay at home. A meter that blends into the process stands a much better chance of being used.

The OLED display is clear and modern. It is not romantic in the way like how a needle meter from decades ago goes, it is designed to be fast to read. KEKS uses a 1.3-inch OLED display, and the display shows the information one needs without making the unit feel unnecessarily complicated.

The other useful handling feature is the choice between single and continuous metering. I generally prefer single metering for film. Point the camera at the important part of the scene, take a reading, lock in the decision mentally, and shoot. Continuous metering is useful when light is changing or when one is moving through uneven illumination, but I still find that film photography rewards slightly slower decision-making (and saves my wallet too).

There is also exposure compensation from -3 to +3 EV. Personally, with colour negative film, I would rather err slightly towards overexposure than underexposure.

In comparison with a handheld meter, the M-Meter is less flexible. A dedicated handheld meter can be used for incident readings, can be pointed independently of the camera, and may offer more advanced functionality. But for the way most Leica M users shoot, especially with 35mm or 50mm lenses, the convenience of having the meter on the camera is a real advantage.

In comparison with older Leica MR or MR-4 meters, the KEKS is more modern and less risky. Original Leica meters have the beauty of period-correct design, but older electronics and old meter cells are always a gamble. The KEKS gives the same broad idea of a coupled meter for a meterless Leica M but with modern electronics, OLED readout, USB-C charging and a new 24 months warranty.

There are, however, handling points to be honest about.

First, the M-Meter adds height to the Leica M4. It does not ruin the look, but it does change the silhouette. Kudos to the KEKS team for aligning the finish and in black chrome or satin chrome, alowing the M-meter to look quite at home. The black paint version, being brass, will likely appeal to those who enjoy brassing and visible ageing over time.

Second, mounting may require a little care. Because the meter couples to the shutter speed dial, it is not as casual as sliding a simple accessory meter into the shoe. One has to align it properly. Once installed, however, that coupling is the entire point of the product and mine stays on permanently.

Third, the display is on top. This means one meters before bringing the camera to the eye, or one lowers the camera slightly to check the reading. This is not a Leica MP, M6-style in-viewfinder meter.

To clarify, some users have discussed battery drain concerns in earlier units, and KEKS has followed up on this feedback with a 2026 updated version that brings improved battery life. It also seems that KEKS has provided owners of earlier units with an updated v2 PCB for installation.

But all these does not make the M-Meter a bad idea. It simply means one should treat it as part of the shooting kit. Charge it before a trip. Do not expect it to behave like a selenium meter from the 1960s or a purely mechanical accessory.

Used with these understandings, the KEKS M-Meter complements the your film Leica M camera rather well.

Conclusions

The KEKS M-Meter is one of those accessories that makes sense only when one understands the camera it is meant for.

On a Leica M4, it is not trying to modernise the camera into an Leica M6 or MP. It is not trying to turn film photography into digital convenience.

the KEKS M-meter certainly does not remove the need to think about exposure as you are still actively part of the process, rather it improves the flow of one’s photography.

What it does is simpler and more useful by gives a meter-less Leica M body a practical, integrated-feeling metering solution while preserving the direct, mechanical experience that makes the Leica M so appealing in the first place.

If one is comfortable with Sunny 16, the film Leica M camera remains beautifully complete on its own. If one wants in-viewfinder metering, then an M5, M6, MP or M7 will make more sense.

But if one wants a meter that feels like it belongs to the camera rather than merely sitting on top of it, the KEKS M-Meter is compelling.

The Leica M4 remains the Leica M4: quiet, mechanical, direct, and beautifully focused on the act of photographing. The KEKS M-Meter simply gives it a little modern help, just the right touch of compromise.

And for many of us still enjoying these vintage film cameras (like my 1969 Leica M4), that may be exactly enough.

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 Leica M4 and the Elmarit-M 28mm, with Kodak Portra 400 (now renamed Ektacolor Pro 400). Development and scanning was done at a typical photo-development shop.

3. The KEKS M-meter was sent by KEKS for review. Usually I return review equipment but this round I will keep the M-meter and purchase another one instead to maintain my neutrality.

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.