Exposed
Posted By Melissa on October 1, 2009
If you missed the last photography post, you can catch up here.
So what do all those settings on your camera really mean?
Let’s start with some basic photography vocabulary that affects exposure.
Film Speed (more specifically ISO): If you want the nitty gritty, you can go here . But basically, the ISO number tells you how sensitive the film is to light. With digital cameras, the number is more symbolic but it still affects how your camera responds to light. The higher the ISO, the more sensitive but also the more grainy. Back in the day of black and white film, manufacturers achieved a higher ISO by making the silver flakes larger (i.e., more sensitive). The larger flakes made for a grainier picture. The same is still true today. You can see a great example here. So basically, it’s a trade-off. I try to use the lowest ISO possible so I can preserve the quality. Usually ISO 100-400 is great for outdoors and ISO 400-3200 is for indoors.
Aperture:Is the size of the opening in your lens that lets light through. It’s defined by f-stop. There’s a lot of mathbehind f-stop numbers but basically you just need to know the smaller the f-number, the larger the hole. Typical f-stops are f/5.6, f/11, and f/22. You also need to know that aperture size affects depthof field (or how much depth of your picture is in focus). Using a large aperture is how one achieves those cool sharp-object-fuzzy-background pictures. Using a small aperture is great for landscapes where you want everything to be in focus from the flower 2 feet away from you to the mountains 2 miles away. There’s a good example of how aperture affects depth of field here.
Shutter Speed: Is how fast the shutter of your camera opens and closes (a.k.a. exposure time). This time is usually represented by the reciprocal of the number of seconds. For example, a shutter speed of 125 on your camera really means that your shutter is staying open for 1/125th of a second and a shutter speed of 1/2 is actually 2 whole seconds. A fast shutter speed is a necessity for “freezing” actions shots or fast toddlers (wink). Slow shutter speeds are good for low light, tripod situations or when you want to see the action like a waterfall shot.
So on your camera, you have auto mode which makes all those decisions for you. But that’s no fun. You also have aperture-priority mode (noted as A, or Av) and shutter-priority mode (S or Tv). In these modes you choose the aperture or shutter speed, respectively, and your camera fills in the other part to create the correct exposure. Av mode is great for portraits or still-life where you want to control how much of the shot is in focus. Tv mode is great for when you need a specific shutter speed like sports.
If you’re really feeling brave, you can go to manual and choose all of the above settings to your liking. You camera probably has an on-screen light meter that reads +3, +2, +1, 0.0, -1, -2, and -3. Or something close to those numbers. 0.0 means your camera thinks your exposure is perfect, anything with a + is overexposed, and visa versa. Note: Don’t always aim for 0.0. It’s fun to experiment. For example, I love the look of over-exposed sunny pictures of kids.
Now that you have some really basic knowledge, go out and experiment. I’d love to hear and/or see what you do!
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