The best light meters don't necessarily replace the one in your camera, but they do let you measure light in ways your camera can't. One day with a light meter can teach you more about exposure than a whole year with an in-camera metering system. So how come?
We’ve got so used to the light meters built into our cameras that we’ve started to overlook their limitations. Your camera’s meter can only measure the light reflected by whatever’s in the frame when you take a reading. It can’t measure the amount of light falling on your subject, which is often more important, and it’s not designed for walking around and checking the light in different areas to get an overall picture of the exposure you need.
That’s what handheld meters are so good at. Most of them come with an attachment for measuring ‘incident’ light and they’re all perfect for checking different areas of a scene. You probably wouldn’t use a handheld meter for handheld photography, but if your camera’s on a tripod, they’re perfect.
And for studio photographers working with flash, they are an essential accessory. Most handheld meters measure flash power as well as ambient light, and your camera’s in-built meter can’t do that. You CAN pay extra for a TTL flash system and just hope that your camera knows what it's doing, or you can get just a flash meter and be in proper control from the start with a much simpler setup.
The best light meters
Weighing just 40g, the Digisix 2 is small enough to fit in a shirt your trouser pocket or hang around your neck via a small strap loop in the base. It offers reflected light readings over a 25 degree angle and incident readings via a sliding translucent dome. It displays a digital readout is in EV, which you then have to transfer to an external dial which then indicates matching shutter speed and aperture values. What's great about the Gossen Digisix 2, apart from its size, is its speed and simplicity. The exposure readout is visible on the top as you point the meter towards your subject or the camera and a single click of the measurement button captures a reading which is stored and displayed right up until you click the button to take another – giving you plenty of time to transfer your settings to the camera. The diffuser slides over the metering cell with a flick of your thumb, making incident readings as simple as regular reflected readings. The Digisix 2 doesn't do flash metering, but there is a Digiflash 2 version which does.
Where the Digisix 2 uses a multi-mode digital readout, the Sekonic L-208 Twin Mate is an analog device that indicates the light level with a swinging needle. You turn a dial to line up an index marker with the needle position, then read off shutter speed and aperture combinations off the same dial. It's a similar manual transfer principle to the Digisix, but with a strong retro look which is more practical than it looks. The position of the needle may look more approximate than a digital readout, but its position on the scale gives a much more immediate sense of how much light there is in the scene. You don't get that just from numbers on a display.
Larger and more sophisticated than the Digisix 2, the Sekonic L-308X is still small enough to fit in a pocket and runs off an easily-replaced AA battery rather than a button cells. It meters both reflected light (over a 40-degree angle), incident light and flash, and offers a digital readout in multiple modes – it also offers cine metering. It's more versatile and powerful than the Digisix 2 but perhaps less useful for metering novices. It's annoying that you have to turn the meter to see the display after you've taken a reading, and while it will give you direct aperture and shutter speed settings on the display, it doesn't display aperture and shutter speed combinations in the same way as a physical dial. the L-308X is a great practical tool, but not such a good learning tool.
This high-end meter offers reflected spot metering, incident metering for both 3D and flat subjects via a retracting/rotating Lumisphere, Cine and Cine HD modes and extensive support for flash, with the ability to measure flash duration, flash vs ambient ratios and wireless flash triggering – plus high-speed sync support and flash duration measurement. Launched in 2016, the Sekonic L-858D was touted as "the most advanced light meter ever". The key thing to understand about the L-858D is that it's two specialized meters in one. It offers spot reflected readings via an eyepiece on the side and ambient readings via the rotating Lumisphere on the top, which can also be retracted/extended to suit different lighting characteristics. This is not, however, a meter for the fainthearted. Instead, it's a high-powered professional meter for photographers and cinematographers who know exactly what they're doing and just need the right tool to do it with.
The Lumu Power 2 is a bit different! It connects to an Apple iPhone via its Lightning connector to transform it into a versatile and accurate light meter. It works with the Lumu Light Meter app to enable you to measure flash or ambient exposure and colour temperature. You can even specify aspects such as your camera’s shutter speed and sensitivity range along with the lens maximum aperture, so you’ll always get applicable readings. It’s also helpful for long-exposure photography as it allows you to add a collection of ND filters and assess their impact on shutter speed. The only reason it's not a little bit further up our list is because it's not especially cheap. It might look like a hipster novelty for smartphone users, but it is in fact a powerful professional tool which harnesses the full power of the iPhone's processor and display to challenge the features of professional meters. The problem is, the price does too, with further in-app purchases to unlock all the features, even after you've bought the Lumu (you can get all the features up front, if you buy the Power 2 Pro version).
Choosing a light meter
Eight things you need to know about light meters
01 Angle of coverage
With in-camera through-the-lens meters the angle of coverage is governed by the lens you’re using or the metering pattern (spot versus average etc). With a handheld meter the angle of coverage is usually fixed, for example 40 degrees. You need to keep this in mind when aiming the meter to take readings.
02 Spot metering
Some more advanced handheld meters offer spot metering. Here, you look through an eyepiece to place a central spot metering area over the region you want to take a reading from. This works just like the spot metering mode on your camera, though it’s easier to quickly take readings from different parts of the scene to work out a median exposure.
03 Incident metering
Here, you slide a translucent dome over the metering cell then stand by your subject to point the meter at the camera position. With incident light metering you’re measuring the light actually falling on your subject, so the reading won’t be influenced by intrinsically light or dark subjects. It’s great for still lifes and portraits in particular.
04 Flash metering
Most handheld meters can also measure flash intensity, and here again you use an incident light attachment from your subject’s position. If you don’t have a handheld flash meter, the only alternative is manual flash with trial and error or TTL flash, which isn’t always available with studio flash systems.
05 Sensitivity range
Handheld meters don’t necessarily offer a higher sensitivity in low light than your camera’s own in-built light meter, so if you plan on doing a lot of very low light photography at night, it’s worth checking the minimum sensitivity value. EV0 is adequate for most artificially-lit situations, but moonlight may be as dim as -2EV and starlight even dimmer at -6EV.
06 Analog vs digital display
Traditional light meters and low-cost modern day equivalents may offer an analog measuring dial, where you line up a pointer with the indicated value and read off possible shutter speed and aperture combinations. Meters with a digital display will quote the light intensity as a numerical value, usually in EV but sometimes in shutter speed and aperture combinations.
07 Aperture and shutter priority modes
Modern meters with digital displays can match the shutter priority and aperture priority modes on your camera, so that if you want to shoot at a fixed aperture value, for example, the meter will tell you the correct shutter speed to use. You may also be able to fix both the aperture and shutter speed values and read off the required ISO setting.
08 Cine modes
Handheld meters have a special importance for high-end video and cinematography where the lighting is arranged with special care. Some handheld meters have cine modes calibrated for frame rates and shutter speeds or, if you’re using dedicated cine cameras, in frame rates and ‘shutter angles’.
How to use a light meter (and why not to trust the camera meter)
Cheat sheet: At-a-glance guide to metering modes
Portrait photography tips
Studio portrait lighting: essential tips and setups explained