Book of the Week: Understanding Exposure

28 Dec 2014

I read Understanding Exposure 3rd Edition by Byran Peterson on a recommendation from a friend who was getting into photography. The 3rd edition was revised to include the advances in digital photography. This book is for people who want to stop using the automatic setting on their cameras and want to explore creatively. The Photography Triangle: ISO, Shutter Speed, Aperture To take a properly exposed photo, you need to understand the photography triangle. Photography is about capturing light and each of the 3 points in the triangle affect how light is captured. ISO determines how sensitive the sensor is. A higher ISO number means the sensor is more sensitive, but can also be noisier. The aperture determines how big the hole that lets in light is. A big hole lets in more light and makes lets things be in focus. A smaller hole makes more things in focus, but lets in less light. The shutter speed determines how long the sensor is exposed to light. The faster the shutter speed, the less light. A faster shutter speed let’s you freeze motion while a longer shutter speed lets you capture and blur flow. If you change one setting, you need to adjust the others to make sure you still have a properly exposed photo. How you make these trades offs depends on what you are trying to achieve creatively. One of the most common things I get asked is how I make the background blurry. I purchase a lens that has a low f-stop, which means it can open the aperture very wide. This makes a small part of the image in focus while the rest is blurred. Another common question is how do I make a photo of water look like it is flowing. This requires a slower shutter speed. One you lower the shutter speed, you need to decrease the ISO to make the sensor less sensitive. You can also make the aperture hole smaller to let in less light. If that still doesn’t cut it, you can put a neutral density filter in front, which will cut the amount of light that passes through the lens. Lastly, it is not the camera you have, but how you use it.