Hand-held Light Meters in the Digital Age
Do photographers really need one?
A light meter measures the intensity of light falling on or reflected from a scene. More properly called an exposure meter, in various forms, they have been photographers’ little helpers for a very long time, but the earliest photographers had to guess. They were educated guesses. Experience taught them much, and when they were still mixing emulsions and coating glass plates that had to be both exposed and developed while still wet, they acquired a sixth sense for gauging the amount of light falling on a scene. The wet-collodion workers created a fantastic body of work through the end of the 19th century, all without light meters.
Even so, it was something of a crapshoot, and the vagaries of the light itself, the variations of sensitivity of emulsions mixed on-site, the weather, and the temperature all combined to make early photography very difficult. I often think of what they accomplished in the mid-to-late 19th century and conclude that if I had to do that to make pictures, I would never have become a photographer.
By the 1880s, with the introduction of dry plates with consistent sensitivity, it became possible to determine exposure more scientifically. However, it was still well before any sort of photoelectric sensor was feasible. Instead, they used charts and/or an “extinction” meter, better than guessing but still requiring that indeterminate sixth sense that only experience teaches.
You’ve heard of the Exposure Triad (Triangle, but I like to sound hoity-toity). Arriving at a “correct” exposure requires having a good read on how much light is available. The controls you have are the shutter, fast or slow, the aperture, wide or narrow, and the ISO, the sensitivity to light of the medium. If you are an analog shooter, the film generally fixes the ISO. A number on the box tells you whether a film is “slow” — needs a lot of light — or “fast,” not needing as much light. Digital allows one to change the ISO from frame to frame.
The big variable is the light itself, mainly its intensity, which is affected by many things. Outdoors in the full noonday sun, it’s very bright. Add a thin layer of cloud, and it’s less bright. Heavy overcast is much less bright, and the time of day matters. We speak of “golden” and “blue” hours. Then there is artificial light, flash or “speed” light, and the list goes on and on.
Never mind the mystery of settings: How do we even know how much light there is? Without a clue, we have no way even to start adjusting camera settings.
When I taught, I often described the “Sunny-16” rule (guideline), which is still helpful if you have no light meter. It assumes full sun on a front-lit subject (sun over your shoulder). So long as you know the ISO of your film (or have it fixed on your digital camera), for your base shutter speed, you put one (1) over the ISO (say, 100) to arrive at 1/100-second. Set the aperture at f/16 and shoot. If not perfect, that exposure will still be very close. If you want a higher shutter speed, say 1/200, open up to f/11 to compensate, and so forth.
This handy chart from SLR Lounge shows variations for “cloudy-bright,” overcast, deep overcast, and sunrise/sunset. Kodak used to print a chart like this on many of its film boxes.
Long ago, I was leading a photo walk and explaining the trick when a learner stopped me to say that the built-in through-the-lens (TTL) meter in her Pentax kept wildly disagreeing with Sunny-16 and was driving her bats. I took the button battery that powered the meter out of her camera, and she relaxed thereafter.
The small lesson there is that conditions easily fool any exposure meter. ALL exposure/light meters are dumb and calibrated to take all the reflectances in their angle of view and recommend an exposure that will average out to 18% or “middle” gray:
Most of the time, this works well if the scene is “average,” with roughly equal reflectances of light and dark, but if the scene is not average, the dumb meter can’t know that, so it adjusts what it “sees” to photograph to middle gray.
We used to give examples of a white cat in the snow vs. a black cat in a coal bin. Assuming the intensity of the light falling on (incident to) both subjects is identical, the two cats will photograph as gray since a reflectance meter cannot distinguish. Neither picture will be acceptable.
The solution to the problem would be to meter off an 18% reflectance gray card or to use an incident meter, measuring the light falling on the scene, but those were not practical for the average snapshooter. They were going to have to accept a percentage of blown exposures.
In those thrilling mid-century days of yesteryear, cameras began to appear with photocell arrays to measure light reflected from the scene. Some were linked, while others at least gave you a starting point for setting your camera. They worked at least some of the time but were nearly useless in low light since they were photovoltaic, not battery-boosted as photoresistors. They needed no batteries, but they were limited.
But today you almost certainly do have a light meter. Just not a handheld one.
For decades now, nearly all modern cameras have a light/exposure meter built in. So far as I know, ALL digitals have one. Your cellphone camera has a highly sensitive and accurate photoresistor that can work in the near dark. So does your $3000+ DSLR or Mirrorless. It’s why you can point and shoot and be confident of a usable outcome 90% of the time.
When working, I owned several light meters, the later ones photoresistor types, battery boosted, highly accurate, that worked in any light, even candlelight. My most (ab)used was a Gossen Ultra Pro that could measure the light falling on a subject (incident), light reflected from a subject, and even flash or combinations thereof. I never went anywhere without it and beat it to death in the studio.
The Sekonic L-358 below is not my meter, but it has all the same features, the capability for measuring flash or ambient or in combination, incident or reflected. For an event photographer from my era, such a meter was mandatory, but since going digital I have not felt a need to have one.
Sekonic L-358 Flash Master: A handheld digital light meter showing an exposure of 1/200th at an aperture of f/11, at ISO 100. The light sensor is on top, under the white diffusing hemisphere. — Wikipedia
So what’s my point? Do I need a handheld meter or not?
Digital allows us to review a shot instantly. Analog never did or could. We had no idea if we blew the exposure until the film was processed. As a wedding photographer, I sweat bricks until the job came back from the lab and it was good. I knew my stuff, knew what I was doing, but countless things could go wrong that I wouldn't know about until it was lawsuit time.
Even today it is possible to have a disaster, but in the field, you can at least “chimp” for exposure and other errors. You can shoot tethered. Pro wedding photographers will have cameras with dual card slots to guard against catastrophic corruption. Any pro will have backups for everything. “Anything you have only one of will break.”
Many of you know I am a committed, passionate mirrorless freak, with my cameras always in full-time live preview.
I see if the exposure is correct before I trip the shutter. I keep one eye on the histogram and the other on the preview. It’s vanishingly rare for me to blow an exposure, which I can quickly correct and shoot again. I think DSLR shooters are more likely to have exposure faults, but they can quickly review after the fact and correct their settings. This makes a handheld meter redundant.
I know pros who rarely use their fabulously $pendy studio flashmeters since they can take a tethered test and instantly see if they need to adjust power or move a light, things we would have thought miraculous thirty or more years ago.
I do not think the modern digital photographer needs a handheld light/exposure meter, not even a spotmeter since most high-end cameras have spot metering built in. If you want one, go for it, but this article's premise was, did you need one, and for me, the answer is simply — no.
Thanks as always for reading! 😊👍
