Nowadays you see lots of people carrying digital SLR (single-lens reflex) cameras around. Question is, do these people really know how to use their cameras?

I will talk about the basic terminologies related to digital SLR photography.

This topic will span across multiple parts, I will share as much as I know, so I cannot really gauge how many parts this will be. I will be as simple as possible with the explanations.

Aperture:

The aperture value of the lens controls the amount of light that is permitted to go to the camera’s sensor. Aperture values are expressed in f-numbers or f-stops (i.e. f/2.0, f/2.8, f/3.5 and so on). The lower the aperture value, the bigger the opening is (more light is permitted); the higher the aperture value, the smaller the opening is (less light is permitted).

The aperture, along with shutter speed, regulates the amount of exposure to light. Aperture is also responsible for controlling the depth of field (DOF). The aperture mode of a camera is used if you want to emphasize a certain object or subject.

A lens with a very small aperture value is considered a fast lens because it is able to permit more light to go into the camera’s sensor. These lenses are typically high cost or expensive.

The photo below shows different aperture values and their corresponding opening sizes. Notice that as the aperture value gets larger, the opening gets smaller.

Photo Credit: pookeyhead

Depth of field (DOF):

As mentioned above, depth of field (DOF) is controlled by the aperture of the lens.

A lower aperture value (i.e. f/2.0) would exhibit a shallower (or decreased) DOF. The object focused upon will be emphasized since it will be the only sharp entity and everything else will be blurred. Using a low aperture value is very effective if you don’t have total control of the environment. If there are lots of distracting objects in the background, utilizing a shallow DOF certainly helps.

A higher aperture value (i.e. f/16 and above) would exhibit a deeper (or increased) DOF. As the aperture value increases, more and more objects will be sharp.

Notice in my example below that the dogs gradually increase in sharpness from left to right as the aperture value increases.

Shutter speed:

The control of shutter speed is used to convey motion.

You will have to use a tripod in order to capture photos using slow shutter speeds. Generally, I have found that capturing, using a shutter speed slower than 1/60, results in blurry images. Shutter speeds are expressed in fractions of seconds, if you see 100 on your camera, that means 1/100 or 0.01 seconds. If you start seeing values that have ” after the number (i.e. 10”), that means you have reached shutter speeds that are in seconds already.

Controlling shutter speed is extremely effective with lights and liquid-related objects such as water. Capturing a waterfall with a slow shutter speed results in a smooth water transition. When a fast shutter speed is used, the water appears rough and abrupt.

The photo below shows the differences between using various shutter speeds.

Photo Credit: Gregory F. Maxwell

This image below, taken by me, was taken using an aperture of f/22 (in order for everything in view to be sharp) and shutter speed of 15 seconds (in order for the water to smoothen out).

Controlling shutter speeds when capturing lighted objects allow you to showcase light trails. A previous post, shows a very good example of how shutter speeds work with light.

You can slow down shutter speeds by either increasing the aperture value or using filters than can be screwed onto the camera lens. The amount of light also affects shutter speed, bring out your digital SLR camera during evenings and you will notice that the camera tells you that you need to use a slow shutter, otherwise nothing will be captured properly.