Incident Light Meter vs Reflected Meter
Are you new to photography and wondering about the best way to choose exposure settings? What’s the difference between an incident light meter vs reflected metering using your camera? In this post, I’ll explain the difference between the two different approaches to measuring or “metering” light. I’ll also fill you in on my preferred approach and tool.
In case we haven’t met before, my name is Kelley Hoagland. I’m a portrait photographer near Chattanooga, TN. My favorite subjects are my husband and three daughters. They would be offended that I didn’t include our puppy in that list.
Incident Light Meter vs Reflected Meter: Why do photographer’s meter light?
I highly recommend learning to use your camera in manual mode. In manual mode, you choose the exposure settings of aperture, shutter speed, and ISO. Making these decisions allows the photographer to be in control of the overall feel of their image.
However, the photographers don’t choose these settings at random. Generally, the photographer wants to get as close to a balanced exposure as possible. In simple terms, the image shouldn’t be too bright or too dark. Either extreme might result in loss of detail, distorted colors, or a lot extra editing time.
How will the photographer know if the camera settings they have chosen will create a properly exposed image? Enter: the light meter.
Light meters measure the amount of light in the scene. They can then predict what camera settings will produce a properly exposed image. There are generally two different types of light meters: Incident light meters and reflective light meters. How do they work and what are the advantages/disadvantages of an incident light meter vs reflected meter?
What are reflected light meters?
Like the name suggests, reflected light meters measure light reflected off of the subject. Think of the light meter in a camera! The photographer points the lens at the scene. The in-camera light meter measures the light that is reflected or bounces off of the subject and into the lens.
Advantages
Practically all modern digital cameras come with a reflective light meter built in. Camera’s offer a variety of metering modes that you can choose between depending on the lighting scenario. Evaluative metering measures all the light within the entire frame. Center weighted metering places greater importance in measuring the light in the center of the frame where the subject is most likely located. Spot metering allows the photographer to choose a specific area of the frame from which to take the reading.
Reflective metering, especially spot metering, works wonderfully when the subject being photographed is far away. Spot metering can be really effective when photographing landscapes.
Disadvantages
Your camera can be easily fooled in certain lighting scenarios. When shooting in back lighting or in a highly reflective environment like sand or snow, your camera may try to under expose the image to compensate for all of the light surfaces, resulting in dark, muddy skin tones for your subjects. Likewise, if the scene is full of dark colors, the camera may compensate in a way that results in overexposure.
Some of these disadvantages can be addressed with the use of a middle gray card (or 18% gray card). To use the gray card, the photographer places the card in the scene they will be photographing. Then, using spot metering mode, the photographer aims the lens at the card while dialing in exposure settings.
With practice, the photographer can also familiarize himself or herself where compensation by 1 or 2 stops might be required.
What are incident light meters?
Incident light meters measure the light that is falling on the subject rather than the light that is bouncing or reflecting off of the subject. Bulb light meters like the Sekonic L-358 are incident light meters. Generally, to take the reading, the photographer stands in the light that is hitting the subject to take a measurement.
Different photographers use different techniques to achieve their desired exposure. We won’t go into all of those details in this post. Techniques range from bulb in to bulb out positions. (Bulb in gives an extra half a stop of exposure.) Some photographer’s choose to rotate the bulb towards the camera or away. Some photographers point bulb light meter towards the ground in order to effectively expose for shadows.
The Expodisc is an incident light meter, which I personally use most frequently. It actually works with the in-camera light meter. To use the Expodisc, the photographer stands in the light that will be hitting the subject and points the camera to the location he or she will be in to take the photo. The photographer covers the lens with the Expodisc while dialing in camera settings and custom white balance. The light is filtered by the Expodisc resulting in an accurate exposure reading.
Advantages
Incident light meters are not as easily fooled by color variations or reflections. Therefore, the have a higher precision when it comes to measuring light for exposure. If you are able to get close to your subject and stand in the light that will be falling on them, an incident light meter will give you the most accurate reading.
Disadvantages
As stated above, to use an incident light meter most effectively, the photographer needs to stand in the light that is falling on the subject. Therefore, while an incident meter would work well for portrait photography, it may not service landscape, wildlife or sports photographers quite as well if the subject is far away.
Incident meters do require an additional purchase of equipment beyond the light meter that is already in the camera.
Incident Light Meter vs Reflected Meter
So which light meter is better when comparing the incident light meter vs reflected light meter? The type of photography you intend to focus pursue will greatly impact the answer.
As a portrait photographer, I have a strong preference for using an incident light meter. When I started metering my light and setting my white balance using the Expodisc, the quality and consistency of my work greatly improved. However, during portrait sessions or when taking snapshots of my family, I have the freedom and time to take incident light readings.
When traveling with my family, I am more likely to revert to reflected metering, especially when taking photos of distant, scenic landscapes or landmarks. When shooting with my old film camera (who’s internal light meter I do not trust), I give up on metering tools altogether and rely on the Sunny 16 Rule.
What light metering methods have you tried?
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