photometer is a tool that allows us to measure light at a specific point and based on this, tell us that ISO, aperture and shutter speed must be used to correctly expose a photograph. With this definition it may seem to us that it performs the same function as our camera when measuring light, however, there are some differences that make it a more effective tool for this purpose,
The main difference when it comes to measuring the light that a photometer has with respect to our camera, is that it measures light directly, unlike our camera, which measures light in a reflected way. What does this difference consist of? When we take photographs with our camera, it knows the light that is in the place to which we focus with our lens because it measures the light that is radiated by what we photograph (people, objects, etc.). The photometer, however, knows the light that is on a person or an object, since we use it by locating it in the place where the light is striking, and this, through the shell (or shell) that it has, records the light that falls on the surface.
This difference is crucial , since the photometer is much more precise indicating how we have to expose our camera since our camera will indicate how correct our exposure is taking into account the reflected light on an average of 18%. This way of working with our camera will work well for us in most situations, but there are times when a photometer will certainly be much more useful to us.
Situations where a photometer is especially useful
- If we are photographing in a space with snow or white backgrounds, our camera will have problems in correctly measuring light, and will tend to underexpose the photograph. It is something that (at least this editor) has lived with all the cameras he has used.
- In photographs in places with very poor lighting, and even in long-exposure photographs, the photometer of our camera can encounter problems when it is confused with incident lights that we often hardly perceive. Using an external photometer on the area we want to focus on will help us.
- Working on situations where we have a very strong contrast. The photometer helps us achieve a perfect exposure where the lights do not burn out or the entire image is underexposed
- Situations in which we have several simultaneous lights(window light as well as artificial light) and we want to calculate how to get the maximum detail without burning our image.
Is it worth getting a photometer?
For most photographers we would say that it is not necessary to get a photometer. By working with digital cameras we have the possibility to readjust our images by reviewing their histogram, so we would not need a photometer. And in cases such as when photographing in snowy environments, knowing how our camera reacts we should only perform an exposure adjustment.
However, if we work making portraits or still lifes where a large number of lights influence and we want to achieve a perfectly light-filled photograph, using a photometer is highly recommended (in fact it is in the situations where they are most often used). Likewise, if we work with old negative or plate cameras that do not have a photometer, it goes without saying that it is essential to use a photometer.
In this case, you can choose to install a photometer on your mobile (note, by using hardware and not just software) and give it a very interesting use , although for more complex situations, the use of more professional equipment such as the Sekonic L-758DR