Exposure is the amount of light you record on the sensor for any part of a frame. First, we’ll talk about the various ways to control your exposure, then we’ll discuss some creative principles and opportunities created by exposure.
There are three ways to control your exposure in the camera they are:
- The sensitivity of your sensor usually expressed in ISO. Lower numbers mean less sensitivity higher numbers mean more sensitivity. Higher sensitivity usually also means more grain or noise.
- The shutter speed, which is how long you expose your sensor to the light. The shorter the shutter speed the less light goes in. The longer the more light you can collect.
- The aperture of your lens, this is the size of the opening in the lens the lets in light. Most cell phone cameras do not have any aperture control, but most real cameras do have some aperture control. All cameras have an aperture– in cell phones and actions cameras the aperture is just fixed and not adjustable.
An additional tool of exposure is controlling your light source. There are actually a few different ways to do that. You can add artificial light by using a flash, or even a household or work light. If your subject is movable, like a person, you can move them into our out of shade. You can also choose where they stand in relation to the light source. And when you combine Exposure with the Frame you can control the use of light or dark in your frame, which is using Exposure in the Frame.
Which brings us to creative principles and opportunities. There are a couple of principles you want to keep in mind with exposure, and they fall into two categories, namely, practical and creative. On the practical side you need to know that your camera cannot capture as much of the light spectrum as your eye can see. Another way of saying this is that your eyes have more dynamic range than a camera. You see this when you make a picture in room with bright sunshine outside. The windows will usually be completely or mostly blown out (white) in the photograph, while with your eyes you can see detail in things inside the room and things outside. That means that in any given scene you have to decide what your will prioritize. Are the highlights outside that window more important than what is in the room, or is what is in the room important? Another practical consideration is noise from high sensitivity. If you are in a dark scene trying to get a clear images eventually you’re making a trade off between noise from turning up the sensitivity of the sensor and blur from camera shake (especially if you’re hand-holding the camera).
The creative principles for exposure are these:
- Human eyes are drawn to bright areas of the image. The brightest areas will attract attention.
- Humans see contrasts more easily and are drawn toward contrast in images. Contrast is where dark areas meet light areas.
- The transition from light to dark can be hard or soft, sometimes you want the light to softly and gradually transition to dark, sometimes a sharp line tells the story you want to tell. Sometimes you want to mix the two kinds.
- Recognizing and learning to use the quality and types of light is a whole skill set for photography, so start learning it.
Here are a few quick exposure opportunities I would like you to experiment with this week.
- Try making a portrait of someone by a window. Let the window be your soft-box and move the person around to achieve just the look you want. A window can be like a big softbox.
- Make two portraits either early in the day or later in the day. One with the person facing into the sun, the other with the sun behind them. You can move around a bit, but the sun should be generally in front in one shot and generally behind in the other.
- Try to make some creative images with strong and sharp contrast–where the darkest darks are black and the brightest lights are almost white. Also make some images with very little contrast and gentle transitions between the moderate darks and moderate light areas of the image.
- Finally, make some pictures of either people or landscapes at noon and either in the morning or evening. Notice what is different about the light.
Exposure is about light, and light is key to making images. Learning to use light, and control it is essential to making great photographs.