How to Use a Light Meter
- Why It's Crucial to Understand Light Metering
- A Beginner’s Step-by-Step Guide to Understanding Metering Modes
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Photographers are artists and crafters of light. Knowing how to use a light meter is an important skill that many photographers have mastered and it is one of the first skills that we learn as beginners.
Virtually all currently produced digital cameras have a built-in light meter and many of these have automation and evaluative metering that help take the guesswork out of much of our photography.
Some photographers, myself included, like to use handheld light meters for photography in certain situations. A question that naturally comes up when considering hand held meters is what is the best light meter for photography.
So let’s cover that part first as we discuss how to use a light meter for various types of photography and cinematography.
Incident, Reflected, Spot
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Depending on how you separate the types, there are 2 or 3 basic categories of hand held light meters for photography. Incident light meters measure light falling on a subject, reflected light meters measure the light reflected from the subject, and a spot meter measures an extremely narrow angle of reflected light.
A few other differentiations among light meter types and how to use a light meter for various photographic applications are ambient light versus flash or strobe, and light meters used for distinguishing what color temperatures or spectrums are in a scene or a light source.
Ambient light light means continuous light, artificial or natural. A meter that is capable of reading the ultra brief bursts of light given off by strobes and flash units is known as a flash meter. Some meters are combinations of several of all of these differences.
Incident Light Meter
Incident light meters like the Sekonic shown above are usually easy to spot due to the frosted dome covering the metering cell. An example of an incident light meter that almost everyone has seen is the Sekonic L-398 Studio Deluxe light meter. You’ve seen this meter used in TV shows and movies that feature a photographer as a character since it has such an iconic look.
Knowing how to read a light meter like this is a general skill in commercial cinematography and videography. Portrait photography takes a lot of cues from cinematography as regards lighting configurations, lighting ratios, and contrast levels, so a meter like is also a good tool for portraits.
Reflected Light Meter
A reflected light meter reads a portion of what can be seen from camera position. Built-in camera light meters are reflected light meters since they are reading what is reflected back from the scene to the camera along with the image itself.
How to use a light meter like this type is similar to how we use a meter built into the camera. From camera position, point the metering cell towards the subject matter.
A lot of reflected handheld light meters for photography have an angle of view between 35 to 45 degrees, or pretty close to what we see with our naked eye or a normal lens.
The Sekonic SKL758DRU-208 is a modern day example of a fine basic handheld light meter at a very nice price point that can get you started in the fun of how to use a light meter. Be sure to check out used examples of these meter types at your favorite local stores or online shops such as MPB.com or Adorama.com. I see many good light meters just rummaging through local garage sales, too!
In use, the meter is reading what is basically an average light value of the entire scene within its view. It’s not going to be evaluating any portion of it like a camera metering program might, simply providing the photographer with raw data of the light intensity exposure value.
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How to use a light meter for spot readings is similar to regular reflected light meters, but the angle of view is smaller. Some handheld light meters for photography have accessories that let you use it as a spot meter, others may be purpose built just for spot metering.
They will all have a viewfinder of sorts so that you can control what spot of the scene is being read. On many of these types of meters, the view will be very similar to that we see in our cameras.
The selective area of what the meter is reading may be a circle or a rectangle in the center that is several degrees wide. About 8 degrees to 12 degrees is common. Or, the selective area might be a 1 degree spot which would look like an AF focus point in our camera.
Spot meters are very good for photographers shooting the Zone System for black and white images or anyone using the same ideas and principles for their fine art photography in color, too.
One of my favorite meters of all time was the Minolta Auto Meter III-F which was an incident light meter that read ambient light and flash but also had interchangeable pieces to replace the incident dome. A flat cover turned it into a reflected light meter, a special probe could be used for macrophotography, and a reflex housing turned it into a 5 degree spot meter.
It’s been out of production for a long time, but you can see it in action in this fun YouTube video about the meter and its versatility. The III-F was replaced by the IV-F which is now rebadged as the Kenko KFM-1100 Pro that is available brand new.
Another current handheld light meter that functions as an incident light, reflected light, and 5 degree spot meter for ambient light and for flash or strobes is the Sekonic Litemaster Pro L-478DR-U light meter.
Now that we have established a good footing, let’s dig deeper into how to use a light meter for our own photography. We’ll cover portrait photography and landscape photography, since the methods, ideas, and techniques transfer readily over to real estate photography, architectural photography, macro photography, small product photography, and most other genres.
How To Use a Light Meter for Portraits
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How to use a light meter for portraits is actually rather simple. Using an incident light meter or a multipurpose light meter with the incident dome attached, place the meter in the same position as the subject. It is now reading all of the light that is falling on that subject.
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Transfer your readings to your camera, choosing the settings that make the most sense for what you’re trying to capture. That’s a big part of why we’re using a hand held light meter in the first place, to bypass the camera automation and be in total control of the process. So, your camera will be in manual mode, as far as exposure settings anyways.
A scene variable that can play havoc with built-in metering systems, even tha cameras with awesome evaluative metering, is very light or very dark clothing. If the meter is seeing a large expanse of light or dark, it’s going to try to compensate.
Instead of relying on a factory preprogrammed group of commands, we take control of the variables involved and craft the image exposure how we want it. No matter how good our camera brain is, in order to craft a work of photographic art, it’s our brain that has the final say.
One of the other ways for how to use a light meter in this type of imaging situation is that we can see a huge number of possible camera settings that will also work for exposure but that may have other implications in our image.
photo by SharafMaksumov via iStock
For instance, let’s say we measured as in the sample shown above with the subject in white clothing and a wide range of color, shadow, and highlight in the background and got a usable meter reading as ISO 200 of 1/250th of a second at f/8.0 being one of the correct combinations.
That will give a great image, properly exposed and balanced. Suppose we want to adjust how much is in or out focus in that background, though. For selective focus techniques, we can see right away that a lens aperture of f/2.8 will require a shutter speed of 1/200th of a second.
For deep depth of field, stopping the lens down to f/16 will yield 1/60th as the appropriate shutter speed. All the while, the exposure values of these settings remain unchanged, we’re simply crafting the exact result we want in our portrait.
How To Use a Light Meter for Landscapes
photo by Don White via iStock
How to use a light meter for landscapes. So now we’re capturing image files of gorgeous landscapes such as what you might see on a specifically planned photo trek or just something you came across as you go about your day of travelling or shooting something else.
The scene, like the view captured above of Banff National Park in Canada, is full of variations in color and exposure values. You can’t walk up to the trees and the mountain in order to use the incident light measuring method.
So you use your reflected light handheld light meter. But, there sure is a lot of different light happening in that scene. The foreground flowers add great interest in our composition but they are at a decidedly different exposure value than the tree trunks in deep shadow.
The water on the lake, the sky near the Sun and away from it, the mountain far in the distance, all have a different light value. We could simply take an average value of the scene and use it, but we want more control.
So, out comes the spot meter or the spot metering reflex finder for our reflected light meter. Using the exposure control ideas we learned as we studied the Zone System, we can meter each separate part of the scene and decide for ourselves how much emphasis we want them to have, controlling that by means of exposure.
The spot metering may reveal that there is just too much dynamic range in the scene as is than what our imaging sensor can handle. So now we know that we may want to employ the bracket and merge HDR technique or maybe use graduated neutral density (GND) filters in order to tame it to our tastes.
Handheld Light Meters Are Very Versatile
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Handheld light meters for photography are one of the most versatile and useful photography accessories for all of the genres of photography, videography, and cinematography.
If you’ve just started on your journey of serious photography, try one out from used stock at your favorite candy store, I mean camera store. Those of you already very familiar with the advantages of and how to use a light meter, keep on finding new ways to use one for having complete creative control.