Whether you’re a professional or a beginner, it’s important to understand how the exposure triangle determines the quality of your images.
Cover image by l i g h t p o e t.
Exposing your images correctly is one of the most important parts of being a great videographer. (It can be hell to try to fix a poorly exposed image in post-production.) A perfectly exposed image can really bring that “it” factor to your video. If you haven’t studied the ins and outs of the exposure triangle, it works like this: there are 3 points of the triangle you have to work with to expose an image correctly — the iris, the shutter, and the ISO. Follow along with these videos as we explain the difference between the three — and how you can make them work in your favor.
The iris of your camera is the ring around the inside of the lens that determines how much light reaches your sensor. This is measured according to “f-stops.” You can manipulate the f-stop through your camera’s settings — or, if you have a lens with a manual iris, through the aperture ring. If your f-stop is high, such as f22, your iris will be small, letting in only a small amount of light, which makes your image darker. The lower the number of your f-stop, the more light will reach the sensor.
The iris also determines your depth of field — or the distance your camera will be able to keep in focus. The larger your iris, the shallower your depth of field will be. If you are trying to get a cinematic shot, a shallow depth of field is usually the best choice. If you are in bright sunlight and can’t open your iris wide enough to get a shallow depth of field, try using a ND filter to darken the image.
Shutter speed measures how much time light will have to hit the camera’s sensor. A higher shutter speed means a darker image since there will be less time for the light to pass through, and a lower shutter speed means more time for the light to do its work. The go-to rule for shutter speed in filmmaking is to double your frame rate. So if you are shooting in 24 fps, set your shutter speed to 1/48, 60fps to 1/120, etc.
Compare your ISO to the gain of an amplifier — the higher your gain, the brighter and noisier your image is going to be. It’s basically digital amplification of your image. You use this primarily in conjunction with your iris — when you want a lower f-stop, you are going to have to bring your ISO down to compensate for the light you’re letting in. You can manipulate this to create a shallow or wide depth of field, depending on the shot you want. Make sure to note of your camera’s native ISO, or the manufacturer’s recommended ISO, as this will be the setting best suited to capture the perfect image.
It takes a lot of testing and experimentation to learn how to expose your image correctly, but knowing the tenets of the exposure triangle really puts everything into perspective when you’re trying out different combinations. Go outside with your camera and see for yourself — you might be surprised how well your images turn out.
Looking for more cinematography and filmmaking tips? Check out these articles.