How to use manual exposure

What you'll learn

  1. What shutter speed, aperture and ISO are and what they do

  2. How to change the various settings in manual mode

  3. Why manual is key for a lot of scenarios

Using manual exposure settings allows you to take full control over your camera, and in turn you can decide how the final photo looks!

What you'll need

  • Camera with manual mode
  • Tripod

Using manual exposure mode is key when you need to ensure each shot looks the same as the last, such as for studio work, timelapses, high speed photos or even for long exposure photography. Manual mode gives you control over the three variables that make up exposure: shutter speed, aperture and ISO. Shutter speed controls how long the shutter is open for, aperture controls how much light gets through the lens, and ISO controls the sensitivity of the camera. The three settings are all connected, so if you change the ISO and the aperture, chances are you’ll need to change the shutter speed too.

Let’s start with shutter speed. Shutter speed simply controls how long the shutter is open for, which means that it also affects how much blur there is in the photo. A short shutter speed is pretty crucial for capturing action without any blur (often referred to as motion blur), however you can use a slower shutter speed to introduce some blur into your photo for creative effect. Shutter speed is noted in seconds and fractions of a second. For example, 1/8000 is a very fast shutter speed, while 1” (1 second) is a pretty slow shutter speed.

The aperture controls how much light is able to enter the camera by changing the size of the hole inside the lens. The aperture consists of a number of blades which move to allow the opening to change in size. As well as changing how much light is allowed in, it also influences the look of the photo by changing the depth of field. There’s a complicated physics explanation for this, but all you need to know is that a large aperture (small number, e.g. f/1.8) gives a shallow depth of field and a small aperture (big number, e.g. f/22) gives a greater depth of field. A large aperture is great for separating a subject from the background and a small aperture is ideal when you want to keep everything in focus.

The final part of the triangle is ISO. ISO controls the sensitivity of the sensor. ISO originates from the days of film cameras, where film would have an ISO rating depending on how sensitive it was. On film, this sensitivity could not be changed, but with digital it can. Typically, ISO ranges from 100 ( a very low ISO) to 3200. This range can of course be even greater. As with the other settings, changing the ISO does have a visual effect on the image. As you increase the ISO, you also increase the amount of noise in the image. A low ISO gives a low sensitivity but also a low amount of noise, a high ISO will give more sensitivity but increasingly more noise.

The finished setup

You should have your camera set to manual exposure and if you’re using a tripod, it should be securely attached.

Capturing the photos