We are teaching an all day photography class in Ephrata on April 23, 2011. Here is a snippet from the class. For more info please check out our website at www.nicklesphotography.com
There are three parts photography’s foundation. I have already blogged about two of them: shutter speed and ISO. The third part to this yummy pie is depth of field or also known as aperture. On your camera it’s called an f/stop. Aperture controls 2 things: how much light your camera sees and what is in focus within your frame. The lower the f/stop number (1.4, 2.8, ect.) the less that is in focus. The higher the f/stop the more that is in focus. The regular f/stops jump in 1/3 increments, but there are many stops in-between. The first thing you have to ask yourself when determining what f/stop you want to shoot at is: what do I want in focus? If there is a big group of people, they all need to be in focus, so you need to shoot at at least f/5.6 Or do you want just on petal on the flower in focus, then shoot at 1.4 (if your lens is able to).
Notice in the picture below the higher the f/stop the more than is in focus.
Second you have to ask yourself “how much light do I need?” The lower the number (1.4,2.8. ect) the more light your camera sees. If you are outside on a bright sunny day your camera doesn’t need a lot of light to hit the sensor to get a good exposure. However, a birthday party at night requires more light. Sometimes you have to sacrifice one for another. Like at wedding reception. I’d prefer for everyone out on the dace floor to be in focus (I would have to be shooting at f/11 or higher) but it’s so dark in there I have to use a low aperture like f/2.8 to allow a lot of light to hit the sensor so we can actually see what is going on.
So there is a trade off. There are so many combinations of ISO, shutter speed, and f/stop to get you a properly exposed picture. The key is to shoot a lot of practice pictures, messing with each part of the equation so you can be ready to know what to pick when the moment hits.