The Exposure Triangle: Bringing it All Together
Camera info: Canon Rebel 350 D • lens 18-55mm f/3.5-5.6
ISO 800 • f 20 • 1/125 sec
Hey my fellow shutter-bugs! It’s been a while since I had a lesson, so I owe you one – and it’s just in time for you to take all those crazy family pictures during Christmas! Previously, I talked about Aperture and Shutter Speed. Today’s lesson is on ISO, as well as answering the question: so what’s the point of all of this?
ISO (International Standards Organization), or as old-school photographers would say, Film Speed, is simply a measurement of how quickly the media in your camera can pick up light. For example, think about the last time you moved. If you had to pack a truck, how long would it take to fill if only you were working? How long would it take if you had a whole team of movers? These scenarios would represent low and high ISO settings, respectively. Higher ISOs “pack in” light faster than low ones, allowing you to shoot better pictures in low light. They also introduce film grain (pixellation) at higher levels depending on your camera.
So now you have all three pieces of the Exposure Triangle, every photographer’s rule to taking properly exposed pictures. The main point is to keep the triangle balanced. When you adjust shutter speed down, you may need to open your aperture or use a higher ISO. When you set a high ISO to shoot at night, you will need a longer shutter speed or wide aperture, etc. You will know these three are balanced when your camera’s light meter is centered.
Now comes the fun part: with this knowlege, you can shoot any camera in manual mode and actually know what you’re doing! 😀 You can try several combinations of the three elements, just remember how else they affect your photos (aperture affects depth of focus, shutter speed affects blur, and ISO affects noise). Also, you can use the Tv, Av, P, and any other settings appropriately. Just know that Tv lets you choose your shutter speed & ISO, and it will pick the aperture for you. Likewise, Av does the same with letting you control aperture. P is fully automatic except for the focus & flash.
Ok, your turn! Try taking some pictures and let us know your experience in the comments. Did you get the image you were going for? Do you know why/why not?