Aperture This is , I believe, the most important part of the exposure triangle. Why, you ask? It is simple. Besides being one of the factors in determining how much light reaches the image sensor, it has the most influence on how the final image will turn out. I want to introduce you to something called” Depth of Field”. We all expect a landscape photo to be crystal sharp front to back, exposing every detail. When you look at a portrait, the background is creamy smooth so it won’t distract from the subject in the photo.
How do you control Depth of Field? Your camera might control this by selecting different scene modes. Look for either Landscape or Portrait modes. If you can set controls manually, you will have greater control on the amount of depth of field in the final image. The smaller the aperture is, the more of the image will be in focus. Conversely, the larger the lens opening is, the less or shallower the depth of field is. So, how do you measure aperture? The aperture / lens openings are calibrated in F stops with 1.4 wide open closing down to 22 at the small end. Each full stop either doubles or halves the amount of light that can pass through the lens. Here are the full stops.
1.4 / 2.0 / 2.8 / 4.0 / 5.6 / 8.0 / 11.0 / 16.2 / 22.0
We were talking about the exposure triangle and how if you only adjust one of the settings, the exposure will change unless you make another adjustment to compensate. It will either be too light or too dark depending on what you did to the aperture setting. If you are closing down the aperture (smaller number) to have more of the image in focus, you can either increase the shutter speed (lengthen the time the image sensor is exposed to light) or make the image sensor more sensitive to light ( increase ISO ) to get the same exposure. Remember to only change one setting a time. You can find yourself chasing numbers . You will eventually get the right exposure, but the moment will have passed by. Stay tuned, we will continue with Make It Your Own, Shutter Speed