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Photography: getting down the basics

Wednesday, February 29th, 2012

There are three elements to creating your optimum exposure: shutter speed, aperture and ISO.

Let’s break it down:

It is first important to determine, what’s most important in the image, depth of field or stopping (or creating) motion. From here, you can determine which to set first.

Slower Shutter Speed

Shallow Depth of Field
Aperture  (or f-stop)- This is what creates “Depth of Field” in an image. A good way to remember is the greater the number, the MORE that’s in focus. This is to say, something that has nearly everything in focus has a LARGE depth of field.  Images taken at f16 or f22 have a larger depth of field while images taken at f2.8 or f1.8 will have a SHALLOW depth of filed. Images with a shallow depth of field typically have one of the subjects in the in focus while the rest is blurred out. Optimum aperture will change with the number of subjects and your distance to the subjects (plane of focus will very greatly with distance).

This image was taken at f16 and has a large Depth of Field
This image was taken at f2.8 and has a very shallow Depth of Field

Shutter Speed-  This is how fast the shutter of the camera opens and closes. The longer it stays open, the more light

you let into the sensor (film or digital). On a sunny day, if you let in too much light, you will get an over-exposed or blown out image. In bright lighting situations you will tend to have a fast shutter speed. Also, a faster shutter speed will allow you to stop motion, for action situations. Slower Shutter speeds are useful in lower light, or when you want to create motion-blurring effects.  Note: In these lower speeds, (below 1/60 s.) a tripod is necessary to stop camera shake.

Slow shutter speed to get detail in shadows- more ambient light. 1/30 sec
ISO- This works much like film speed- it is the sensitivity of sensor to light. The lower the number, the less sensitive to light, the higher the number the more light the sensor picks up. On a sunny day, one would use a low ISO at say, 200 whereas a person in a darker room working without a flash would crank up the ISO to say, 1600 to make the sensor more sensitive, grabbing as much light

as possible. A higher ISO grabs more “ambient” light. There is a compromise with using higher ISO’s, the images is less crisp and more

grainy. However, with cameras these

days, the ISO capabilities are becoming more and more impressive.

This image was taken in almost complete darkness, save for the streetlight.         ISO 1600
A deep understanding of these elements and how they work together, is what sets a professional apart from the amateur photographer.

Fast Shutter Speed to capture the movement and a Large Aperture to blur the background