When we see an object we are basically seeing the light reflected from it. When we take a photograph our cameras capture those light rays on the sensor (photography essentially means "light writing" ) For the purposes of taking great images, we need to know how light affects our images, and how we can control it and use it to our advantage. Today, I'm just going to give an overview on the different ways light affects our images (Please note that I'm generally talking about natural light here - thousands can be spent on getting the light exactly how you want it in a studio but I prefer the free version - the sun!)
Exposure is essentially how light or dark the scene is. We generally strive to reach an exposure that looks like how we saw the scene with our eyes. We have looked a lot at how we try to get that correct exposure in camera by first understanding how our camera "sees" light, the different ways your camera can measure for it, and how we can compensate to get the exposure right in camera. Knowing how the tones in your image will impact on exposure helps you to get this right in camera.
Light also has color and this can vary greatly depending on the light source, whether it is cloudy or sunny, and even the time of day. These different tones can be warm or cool, and are measured in Kelvin (You may have heard about using Kelvin for white balance) For example, sunlight might measure around 5600K during the day, but can drop to 4000K in late evening. Lightbulbs measure at around 3200k. Our eyes automatically adjust so we don't see these color temperatures but our camera can't. This is why we set our white balance either by choosing the appropriate light source WB in camera, or using a grey card to set the white balance manually.
Yes, believe it or not, you can get good or bad light. Light can be either hard or soft, and generally speaking, softer light is much more flattering for most types of photography. The time of day you take your photographs in is very important to get good light quality. For example, the sun's light is at it's strongest at around noon, which creates a very harsh light. Very few photographers will schedule a photo shoot at this time because the light at this time is very unflattering for portraits. The best time to take photographs is an hour before or after sunrise, as the light is much softer then - and ultimately more flattering. However, if you cannot manage this (I have yet to get myself and Callum up and dressed for that time of day!) then still try to get your pictures earlier or later in the day when the sunlight is a bit softer. Cloudy days are also great for portrait shots - the clouds diffuse the harsh light of the sun and act like a giant softbox, making it pleasing and soft.
The direction of light is also very important. Again, midday is not a good time for taking pictures due to the direction the light will fall. As the sun is high above your head, shadows fall straight down giving your subjects shadows under the eyes or chin. Shooting earlier or later on in the day will give a better direction of light as the sun is lower to the ground. Another thing to think about is the position of your subject in relation to the light source. A photograph can look very different depending on whether it is side, front or back lit. Side lit can give your portrait more depth and add more visual interest. Back-lit images are more hazy and produce dreamy images. Lighting from the front creates even skin tones and great catchlights in the eyes (make sure that with front lit your subject is not having to squint) Each can provide glorious, yet very different images.
This was just an introduction to light - there are going to be a few tutorials coming up on light, including how to use the light to create different portrait shots (side-lit, back-lit etc) how to read and understand a histogram to check exposure, tricks for seeing and understanding the direction of the light, and even how to use Kelvin for white balance (gosh, I'm going to be busy!) but hopefully this will start to make you aware of how important light is in your photographs, and therefore why we should strive to understand it.
If you have questions or comments, please feel free to leave them below!