The Reveni Labs Lumo is a tiny multi-function light meter. Incident metering, reflective metering, flash metering with ambient ratio, colour temperature, flash duration analysis, cine mode. CNC-machined aluminium body, user-replaceable rechargeable battery, sync port for external triggers. It does almost everything a Sekonic L858-D does. It costs around CAD $200. That is the entire pitch and it is a very good pitch.
I drove from Toronto up to Hanover, Ontario to visit Matt Bechberger at the Reveni Labs lab, partly because I had been planning the trip anyway and partly because Matt had just launched the Lumo on Kickstarter. The Kickstarter blew through its funding goal in 51 hours, was at 235% funded by the time I arrived, and did not need my help in any meaningful sense. But the rental car was booked and the road trip was happening, so I went.
This is the review. The short version: if you can live without a 1-degree spot meter (which the Lumo does not have), this might be the best-value light meter on the market.
Driving to Hanover
Hanover is about 200 kilometres north-west of Toronto. Small town, rural, properly cold in early February. The drive was beautiful: snow-covered farmland, lots of cedar trees, the kind of empty Ontario landscape that I do not see much of from inside Toronto.
Matt’s lab is small and immaculate. He runs Reveni Labs as a properly serious one-man operation: camera testers in the corner, prototype boards on the bench, products in various stages of design and revision. The Mark 2 of his spot meter was on the bench (he has dropped the coin-cell option and gone AAA-only on the new revision). The Lumo prototype was charging.
Matt is exactly the sort of person you want building light meters. Technically deep, patient with questions, willing to explain the same concept three different ways until you actually understand it. We spent the better part of a day going into the weeds on flash duration, t-times, colour temperature measurement, and what electromagnetic radiation a light meter is and is not measuring. The long version of that conversation is on Patreon. The version below is just the practical bits.
![PLACEHOLDER: the Reveni Labs Lumo in Matt’s hand at his lab in Hanover, Ontario]
What the Lumo actually is
A multi-function light meter the size of a small dice. Roughly the volume of a wallet folded in half. Weight is negligible. The body is 6061 aluminium, CNC machined, black anodised. Three buttons on top, all solid aluminium. Small LCD on the back showing all the readings.
It does the following:
Incident metering. Diffuser dome on top. Hold it where your subject is, point it at the light source, press the top button to take a reading. Standard incident workflow.
Reflective metering. Front-facing sensor. Press a button to switch modes. Roughly 45-degree angle of measurement (not a 1-degree spot, which is the main thing missing compared to the Sekonic).
Flash metering. Set the meter to flash mode, press a button to start watching, fire the flash. The meter reads the flash burst and tells you the correct aperture for your chosen ISO.
Flash plus ambient ratio. This is the feature that sets the Lumo apart. After taking a flash reading, the meter also reads ambient light immediately afterwards and shows you the ratio between the two on the screen. You can see at a glance how much your flash is doing versus how much the ambient is doing. This is normally a feature you only get on much more expensive meters (the Sekonic L858-D has it as a bar graph). On a $200 meter, it is extraordinary.
Colour temperature. A separate sensor measures red, green and blue channels and the meter converts to a Kelvin value. Tap the button for an instant reading, or hold a button for continuous live readings. Useful for cinematographers and for anyone setting up mixed lighting.
Flash duration analysis. T-time measurement (the duration of the flash burst). Same use case as the Sekonic’s flash duration feature: tells you how your flash actually behaves at different power settings.
Cine mode. Replaces shutter speed with frame rate and shutter angle. Useful if you are shooting motion picture work with film cameras, where you cannot just check a histogram.
Lux reading. Linear measurement of brightness. EV0 is one lux, EV5 is 100,000 lux (which is roughly direct daylight sunlight). Useful if you want a raw brightness number rather than just a recommended exposure.
Sync port. A 3.5mm port on the side that can either accept a remote release or trigger an external flash. Means the meter can also serve as an optical slave trigger for flashes that do not have one built in.
![PLACEHOLDER: the Lumo screen showing a typical reading with EV, shutter speed, aperture, colour temperature and lux all visible]
The Sekonic comparison, which is the actual point
I have just published a review of the Sekonic L858-D SpeedMaster, which is currently the gold-standard professional light meter. The Sekonic does:
- Incident metering
- Spot metering (1-degree)
- Reflected metering
- Flash metering with flash-to-ambient ratio
- Flash duration analysis
- Cine modes
- Lux
The Lumo does almost all of the same things. The big exception is the 1-degree spot meter. The Lumo’s reflective mode is roughly 45-degrees, not the tight 1-degree spot the Sekonic offers.
If you do not need the 1-degree spot, the Lumo is essentially equivalent to the Sekonic at one-fifth of the price. Around CAD $200 versus the Sekonic’s $650-ish.
If you do need the 1-degree spot (and there are workflows where you genuinely do, like paper reversal portraiture or zone-system landscape work), Reveni Labs sell a separate spot meter for around CAD $200, which I have used heavily and which is excellent. Combined cost: CAD $400 for the Lumo plus the spot meter, both pocketable. Still well below the Sekonic.
This is the genuinely useful comparison. The Sekonic is the gold standard and it deserves its reputation. The Reveni Labs combination gets you 90% of the way there for roughly two-thirds of the price, and in two smaller pocketable devices rather than one larger one.
For most film photographers, the Reveni combination is the right call. The Sekonic justifies its price only if you need everything in one body or you specifically need the 1-degree spot in the same unit as the incident metering. For paper reversal work where I genuinely do need the tight spot for face metering, the Sekonic is the right tool. For most general shooting, the Lumo plus the Reveni spot meter would be all I need.
Build quality and the day-to-day stuff
The Lumo feels properly built in the hand. Solid aluminium body, no flex, no creaky panels. The aluminium buttons have a satisfying mechanical feel. The screen is clear and readable in direct sun (which not every electronic meter manages).
The battery is nickel-metal hydride, user replaceable, rechargeable in place via USB-C. This is the right call. Lithium batteries have their fans but a user-replaceable rechargeable NiMH is more practical for a tool you are going to be using for years. You can swap a worn-out battery without having to send the unit back.
The size is genuinely small. It disappears into a jeans pocket. The Sekonic L858-D, by comparison, is the kind of thing you remember to pack and then wonder where to fit it. The Lumo you just carry without thinking about it.
The field test, in Ontario snow
We took the meter out into the snow at Matt’s place. I had brought my Stenopeika Air Force 4x5 and a small stack of Fuji Velvia 4x5 sheets. The plan was to shoot Matt as a portrait test, with the Lumo doing the metering. Velvia is unforgiving (slide film, narrow latitude, blown highlights cannot be recovered) so this was a proper test of whether the meter could deliver accurate exposures from a prototype unit running prototype firmware.
The walk to find a shooting spot involved crossing a frozen river. Matt was casually confident. I was less so. The edges were thick ice, the middle less thick. We made it across without incident. The cedar trees on the far bank were beautiful in the winter light, and apparently the local deer eat the cedar leaves all winter, which I had not known.
Set up the camera, framed Matt against the trees. Two lenses with me: a Schneider 210mm (proper modern lens with conventional aperture markings), and an Emil Busch (an antique lens with no shutter and aperture markings that I genuinely could not decode, just numbers that double in sequence with no relation to f-stops I recognised).
First test: Emil Busch lens, hand-timed exposure. Took an incident reading from Matt’s face with the Lumo. The meter said 1/15th at f9 on ISO 100 Velvia in the current light. I set the lens to what I guessed was roughly f9 (the markings were uninterpretable so this was a best guess), and hand-timed a 1/15th of a second exposure with my hand over the front element.
The frame came back well exposed. So either my guess on the aperture was lucky, or the Lumo’s reading was forgiving enough that some aperture-guess error was tolerable, or both.
Second test: Schneider 210mm, proper apertures and shutter speeds. Stopped to f5.6. The Lumo gave us 1/30th. Set the lens to 1/30th at f5.6 using the Reveni Labs remote release (which is, incidentally, one of my favourite bits of kit in any category). Fired the shutter.
Then re-metered for 1/40th to be safe, but 1/40th was not an option on the lens, so I stayed at 1/30th. Shot another sheet. Then a third with Matt smiling for fun. Three Velvia sheets in total.
![PLACEHOLDER: the developed Velvia frame of Matt against the cedar trees, properly exposed]
The frames came back properly exposed. Not a single blown highlight on the Velvia, which on prototype firmware in a brand new meter is a genuinely impressive result. The Lumo metered correctly.
Who this is for
If you shoot film and need a small, pocketable meter that does almost everything you need, the Lumo is the obvious recommendation. The price is excellent. The features are extraordinary for the category. The build quality is solid.
If you specifically need a 1-degree spot meter (paper reversal portraiture, zone system landscape, very precise highlight control), you will also need a Reveni Labs spot meter or a Sekonic to go with it. The Lumo alone does not do tight spot work.
If you are a working professional whose income depends on a single meter doing everything, you might still want the Sekonic for the integrated workflow. Or you might prefer two specialised tools for the same money.
For everyone else, including hobbyists, serious amateurs, photographers who want a reliable backup meter, and anyone curious about flash-ambient ratios without spending Sekonic money, the Lumo is a remarkable piece of engineering at a remarkable price.
A note on Matt and Reveni Labs
I have ended up reviewing several Reveni Labs products on the channel over the years and the pattern is consistent. Matt designs tools that solve real problems, prices them honestly, builds them properly, and supports them properly. The wireless remote release is on every shoot I do. The original spot meter has been a reliable companion for years. The Lumo joins that family.
Reveni Labs is the kind of small business that the film photography world is lucky to have. Buy his products. They are good.
You can find the Lumo on the Reveni Labs site, now post-Kickstarter and available for direct order. The current price as I write this is around CAD $200, which is roughly USD $140, although prices may have shifted by the time you read this.
Big thanks to Matt for the day and the hospitality. The frozen river walk is a memory I will keep for a while.