Getting a correct exposure is one of the most important things in photography. See why that is here. So here are 5 things which will affect your exposure. Knowing these will help you to understand when you need to change your exposure and what settings to change. But first I need to explain that the biggest and most important thing to think about when reading this is light. Light is what makes a photograph and without it you will find capturing an image pretty difficult. So throughout this article when I talk about exposure I am also referring to light, both natural and artificial.
What you are shooting and how you want your subject to look will have a big effect on your exposure. For example a portrait shoot allows you to bring in lights and reflectors, but with landscape photography it is not so easy to do this.
If your subject is moving you will need to use a fast shutter speed to freeze the movement. Or if you are looking for a bokeh effect, then you will want to use a small depth of field.
The colour of your subject can also affect how you light it. Darker colours absorb light and therefore more light will be needed to capture the image. Lighter colours reflect light and therefore need less light to capture the image.
Where you are
This can affect what natural or artificial light you have around to light your subject. If you are outside on a sunny day then you have plenty of light and will find it easy to get a good exposure. But if you are indoors you may be relying on light from a window or artificial lighting which is not as easy to work with.
You will also need to think about the colour of your surroundings. As mentioned above, dark colours absorb light and lighter colours reflect it. So if you are in a snowy environment then you will find that it is very easy to over expose your image.
Time of day
I think everyone is aware that there is a lot more light during the day than at night. But the time of day can also affect your exposure. Daylight is constantly changing, so you may see something which looks beautifully lit by the sun, but by the time you have got your camera out, the light has changed. This happens to all photographers.
As the sun moves across the sky the direction of the light will also change. This means that your highlights and shadows will be on opposite sides of your subject in the morning compared with in the afternoon. You may also hear photographers talk about the golden hour and the blue hour. The golden hour is just after sunrise and just before sunset. The Blue hour is just before sunrise and just after sunset. These are often considered the best time of day to shoot because of the softer light and different colours which the sunrise or sunset can create.
Weather Obviously there is more light on a sunny day than on a cloudy day. However many photographers actually prefer to shoot on a cloudy day because the light is softer and there are less harsh shadows.
Other weather such as rain or mist can also reduce the amount of light and you may need to adjust your exposure for them.
On the other hand, snow and ice can increase the brightness because of how much light it reflects. Therefore you will need to reduce your exposure.
The sun is not the only light source available. As I have mentioned earlier you can also use artificial lights. These come in many forms; flash units, studio lights, standard indoor tungsten light bulbs, florescent light and more. These work with natural light (sun or moon) to create your exposure. In some situations you may just use an artificial light to brighten the shadows and give a softer overall look. In other situations you may use artificial light as your main light source. With artificial lights you can often control the power of it, either with a dial on the light or by moving the light source further away from or closer to the subject. This can give you very precise control over your exposure and many photographers will spend time before a shoot working out what the best lighting and exposure will be. With artificial lights you can also create interesting effects by adding coloured or patterned filters. These will of course reduce the light on your subject and you will need to adjust your exposure.