Article and Photos by Stuart Blower © 2024
Beginners are still trying to understand it, and many long time photographers have gotten past the basics of correct exposure with their cameras. They may intellectually know that you can change the shutter speed which changes how you capture motion. They may know that changing the aperture affects what you focus on, but that doesn’t mean they’re actually using those things as options when they capture an image.
You might know it intellectually, but we need to practise bringing it into regular use, by pushing past your comfort zone.
This is all about training your brain to see differently with options in mind. How you use the tools of your camera to take a picture should be fun and easy. It’s the training and the repetition that make it second nature. Then it does become fun because those tools are right at your fingertips.
Depth of Field
Most of us are aware that it’s influenced by the aperture that you pick, but do you actually go out of your way to do that? This is an excellent compositional tool for highlighting somebody and separating them from the background.
For beginners, when you take a portrait and focus on the eye, that is the only part of the image the lens makes sharp. The zone that extends in front of the eye that includes the nose and behind it, like the ears, need help from the aperture or iris to also be in focus.
The aperture is an iris inside the camera lens that opens and closes to help regulate the amount of light that enters the camera body. The larger the number, the greater the “Depth of Field making more of your image in focus.
Smaller aperture numbers ie: (f 1.2,f 2, f2.8.) on your lens mean larger lens opening and larger diameters of glass, correspond to less “Depth of Field.” Less in focus, in front and behind the actual point you focused on.
Larger numbers such a f8, f11, f16, f22, indicate small lens openings and this small opening does contribute to making a larger focus zone. It actually spreads out the focus both closer to you and farther away from you, allowing the entire head to be in focus.
Shutter speed.
Very fast shutter speed (500, 1000, 2000, 4000) will freeze action that is too fast for the eye to follow, for example. sports, birds in flight dragonflies vibrating their wings.
But shutter speed can also go the other way and be very slow(1, 2, 4,15,). What happens then? Well either people walk by your camera in a blur or you “Pan” with them and they’re sharp and the rest of the background is blurred with motion
Exposure Iso
The combination of depth of field aperture and shutter speed should be floating around in your brain. It’s a balancing act. If any one of these is either too extreme or not extreme enough for the conditions you are shooting under, then you need to change the third component, the ISO.
Higher ISO numbers increase the sensitivity of the camera sensor, by providing electronic amplification.
This means your camera will amplify the existing light. You can shoot in lower light with higher shutter speeds or use more depth of field. Todays cameras are extremely good at providing decent images at higher ISO settings,
Photographers should experiment with the limits of their own camera ISO settings, when the light goes down. You either have a lens that has a very wide aperture to gather the light or you need to increase the ISO speed to capture the image
Take the time to experiment and know what your camera can do. Find out how high your ISO speed will go and still give you acceptable results.