Thursday, April 23, 2009

exposure triangle

During a break in the photo shoot for alice rose, her mom brought over her brand new Nikon D60 for some quick tips on how to use it. So I sat down for what I thought would be a straightforward tutorial, and a bunch of gibberish came out of my mouth. I tried to explain ISO, aperture and shutter speed to a new mom, no less, and I'm afraid I just confused her. Which then made me worry that maybe some of my lessons are too obtuse? Too abstract? Too much detail? (send me an email if you have an opinion on that) I figured now is a good time to review the basics of photography again. But first, an analogy:

Growing up, I took dance classes. Lots of them. I loved tap and jazz, and later when I went to college I dabbled in modern and African dance. But I never really warmed up to ballet - I thought it was slow and boring. Only after taking dance classes in college did I realize the importance of ballet to the art form of dance - the techniques you practice in ballet form the backbone for most other forms of dance. I wished many times I had taken ballet from the beginning, rather than trying to play catch up in my twenties.

Generally speaking, there are 3 main components to a good photo: exposure, composition, and focus. Think of ballet as the exposure component - you may have a great eye for composing interesting photos, and you understand how to focus your camera, but if you cannot get the correct exposure for your photograph then you're missing out on a truly great photo. Sure, you can use editing tools to correct your mistakes, but sometimes that leads to overly processed photos.


The "exposure triangle" is comprised of: (1) aperture, (2) shutter speed, and (3) ISO. You can click here for a review of my lesson on aperture and shutter speed. In a nutshell, ISO is the sensitivity of your film, or in digital photography, your image sensor. The lower the ISO, the less sensitive your camera is to light. For a more detailed explanation click here (courtesy of Digital Photography School). These three concepts work together for the perfect exposure, hence the "triangle" concept. A change in any "angle" of the exposure triangle will necessitate a change in the other angles.

Digital Photography School has a good article on the exposure triangle - one metaphor used to explain it is a window with shutters: the aperture is the size of the window (lower f-stop = big window, higher f-stop = smaller window); the shutter is, conveniently enough, the window shutters. Shutter speed is the amount of time the shutters stay open before closing on the window. ISO is you sitting inside the room with sunglasses on (so you are desensitized to how much light is coming in - like a low ISO setting). There are many options to achieve the optimal light in the room - increase or decrease the size of the window (aperture), increase or decrease the amount of time the shutters are open (shutter speed), or take off your sunglasses (ISO).

These concepts may be basic and essential to good photography, but they are not easy to master by any means. Practice makes perfect. If any of you have a specific question about your camera settings and how to change aperture, shutter speed or ISO leave a comment or send me an email - I'd love to help.


Anonymous April 24, 2009 at 8:27 PM  

This post actually helped me learn a little more about ISO. I was trying to take a shot of something outside, and it was fuzzy because I didnt have the proper ISO number. I wasn't paying enough attention to the light that was coming in from outside and they came out fuzzy. So, thanks!