Light Meter: How it Impacts Photography Exposure

Light Meter in Photography

Light meter! The device is not often heard when it comes to photography but is an essential tool to get the exposure of a photo right. Even though, for a seasoned photographer, it’s easy to ascertain the exposure values for a specific scene due to his knack, knowledge, and experience. But for a layman, it’s pivotal to take advantage of this device is to detect how much light is falling on a scene. The device will assist you to adjust the aperture, shutter speed, and ISO resulting in a correctly exposed photograph. It comes in various forms and can be utilized in different methods.

No matter how you capture or whichever shooting mode you fancy using, there is one device that remains fixed and that is the light meter. Your camera must sense how much light is present in a scene that is to be captured. Having substantial knowledge of the uses and effects of this is crucial to refine your photography skill and achieve the shots you intend. Even though the present-day camera has a built-in light meter inside the camera, it can be tricked in different lighting conditions. You, however, expect an accurate brightness of the scene that you wish to snap and so you have to carry out it appropriately. This is where a hand-held light meter comes into play as it provides you a better grip on the exposure of your photo.

Light Meter and its Types

Light meters come in handy in stiff lighting conditions and also when subject matters are complex. When you photograph a scene, you crave different tones in your image. You want to add shadows and highlights to your image. It tracks down the spot in an image where you can achieve a variety of tones by metering the amount of light striking the sensor. This allows you to protect your image from overexposure and underexposure. There are basically two types.

In-camera: The biggest advantage of an in-camera light meter is that it’s built-in and available with your camera. You don’t have to worry about an external light meter. Basically, this type comes in 3 modes: spot, center-weighted, and evaluative. When you go for spot metering, it focuses on one spot of your image, mainly, the center but if your focus point is selected elsewhere, it will measure the reflective light of that spot. The center-weighted mode is similar when it comes to focusing as this mode also focuses on one spot but the difference is that it averages the tones of the remaining frame. Last but not least is the evaluative mode which averages 100% tones of your frame and ensures an even photograph.

In-camera Light Meter


Hand-held: Hand-held light meters are conducive for film cameras as there are no built-in forms in film cameras. Film cameras, however, are old-fashioned now as DSLRs have superseded them. Even though DSLRs have built-in light meters, many film shutterbugs prefer making use of hand-held meters to save time and bring perfection in the exposure. Not only film shooters but also digital photographers count on hand-held light meters for incident metering for studio shooting. This helps them to save their precious time as they don’t have to conduct trial and error-based guesswork in tricky lighting conditions.   

Hand-held Light Meter

How to Use a Light Meter in Photography

As stated earlier, it predominantly comes in 2 different forms. There are 2 ways to measure the amount of light present in a spot while taking shots- reflected and incident. When it comes to built-in form, it is capable of measuring the reflected light. Generally, DSLRs that you use boast a built-in or reflected light meter which measures the measured reflected light. The light source strikes the subject and is reflected towards the camera. This reflected light by the camera light meter. If you are deploying automatic mode, the camera shutter speed and f-stop value will automatically calculate it.

On the other hand, if you use a hand-held one, it is capable of measuring both reflected and incident light. And to achieve perfection in the reading, it’s key to meter the incident light. In order to nail it, you have to place the incident meter adjacent to the subject and point it towards the camera. This enables the device to meter the light falling on the subject directly from the light source as opposed to the reflected light. As a result, you get the accurate value of the light. This comes in handy more if you deploy flash while working as it can measure the intensity of the flash and deliver you the accurate shutter speed and aperture value of your photo.

An Analogy to Comprehend Light Meter Better

Did you ever try cooking meat on a grill? No matter whether it’s chicken, beef, steak, or hamburger, you certainly thought about the final output of that how it would look like before you start cooking. If you are an amateur cook having no idea about the food condition while cooking, you can use a meat thermometer to have an idea about the temperature. The thermometer reading will help you to know when the food is cooked. Now, the question arising in the mind is where to place the thermometer to check whether the meat is cooked. If we rephrase the sentence in terms of different photography types, it will be, where to place the thermometer to check whether the meat is correctly exposed. What you can do is, touch the meat on the surface, poke various parts of it and insert the thermometer at different points to achieve the exact reading.

The above analogy is handy to discern the function of a light meter in photography exposure. It’s comparable to the thermometer. With the correct placement of this device, you will get the actual amount of light hitting the sensor for a particular scene. This will enable you to get a correctly exposed frame or image.

Incident vs. Reflected Light Meter

As discussed earlier, an incident light meter measures the light directly falling on the subject whereas a reflected light meter measures the light reflected off the subject’s surface. A hand-held meter is always accurate as compared to an in-camera meter when it comes to securing perfect reading. To fathom this point, you can think about the situation. If a person is standing in the sun during the noontime, the incident light under the chin and in the nasal bridge won’t be identical. This is due to the direction of the incident meter towards the light falling directly on the subject. Contrariwise, a reflected meter is pointed towards the subject and the light reflected off the surface is metered.

So, the main disparity between the two is, an in-camera light meter measures the reflective qualities of the surface whereas a hand-held camera measures the exact power of the light source. For example, if you are wearing a black overcoat and use a reflected meter, the exposure of the overcoat will read low even if you use a powerful light source. In this case, you are likely to overexpose other portions of the image. This is where an incident meter comes into play as it will read the perfect value of the light source, thereby exposing the entire image correctly.

Dynamic Range

Dynamic range is a crucial concept in the case of photography exposure. The ratio between the brightest and darkest regions of a scene is what we know as dynamic range. When a photographer looks to capture a scene, he endeavors to end up shooting a scene that is neither too bright nor too dark. So, from this angle, dynamic range implies the total amount of light captured in a given scene. If a scene is snapped having a flurry of bright parts full of lights together with a lot of dark parts covered with shadows, it can be pinpointed as a high dynamic range. On the contrary, if a scene is illuminated in such a way that it is neither too bright nor too dark, it can be described as a low dynamic range. The middle point of a dynamic range is 18% grey which every light meter takes as a benchmark for supreme exposure.

Winding Up

We attempted our level best to shed light on the operation of the light meter, and how you can achieve the best shots availing it. As a matter of fact, there is no one way of stating that this particular way can guarantee you to attain the best shots. In fact, all the methods and metering modes will operate based on the scene you are shooting and the types of results you are anticipating.

Apart from the methods and metering modes, it’s also pivotal to perceive how light is measured when it hits the camera. This will also assist you to notch up the shots you crave for. Overall, the more you acquire knowledge about the modes, methods, and lights, the more you are likely to fly in photography exposure. On top of that, the experience of working with a light meter will also boost up your confidence and provide a better idea of how to correctly expose your shots.