There are three interdependent variables in digital photography.

Digital photography consists of a proper balance between...

Shutter Speed

Aperture

Film Speed

Throughout the pages of this site I talk about how these three interrelate. When you understand and find the correct balance your snapshots will transform into photographs.

Don’t concern yourself if you don’t understand this page right now. Read it and refer back to it periodically. After a time you will comprehend the information. It is important in the grand scheme of photography, but it is not important that you digest it all right now.

Remember exposure is how much light reaches the photosensitive area of your camera? This is what determines how bright or dark your pictures will be. Different subjects require different amounts of light to come in contact with the photosensitive surface.

People think that shutter speed is what makes the difference in digital photography. It does, but, shutter speed is only one of three variables that change exposure (brightness). The settings you choose for shutter speed, aperture and film speed, all affect the exposure in digital photography.

This is important! You cannot merely use shutter speed changes and expect professional quality photography. The other settings are there for good reason. Learn to use them and you will be a much happier photographer for your effort.

The settings of these three decide... how dark or bright your pictures end up. The three must be balanced in order to have good photos. Let’s see if I can put it into words.

Large hose, high water pressure,(where water is the light entering your camera) and a wide open nozzle equals lots of water moving through the hose. Restrict any of the three and it takes longer for the water to move through the hose.

Shutter speed is like... an on/off valve that has only two settings. Either it’s on or it’s off. The speed at which it is switched on then off determines how long the water (light) runs through the hose. In essence how much light actually travels through can be restricted by the time duration of the shutter.

Aperture is the size of the hose.

A drinking straw size hose, good luck watering you lawn. But a hose the size of a fireman’s hose you will wash your lawn into the gutter. So---- small aperture equal little light, large aperture equal lots of light.

Film speed is equal to the water pressure in the hose. Slow film speed (low pressure) requires more time and gives more detailed results. Fast film speed (high pressure) requires little time but offers less quality.

Slow film speed quality.

Fast film speed quality.

As you can see changing any of these three will affect the amount of light hitting the “Image Sensor” inside your camera. Each affects the other two. If the exposure is to remain the same, one or both of the others must be adjusted to balance out the equation.

Let's see an example.

Let’s say a picture needs a shutter speed of 1/1000th of a second and an aperture opening size of f8 at a film speed of 400 ISO.

Now let’s say I want the tree branch in the fore ground blurred so as not to detract from the stage coach. I will need a larger aperture. That means substantially more light entering my camera if I don’t change either the film speed or the shutter speed. That translates into over exposure of the shot.

But, if I use a slower film speed, more light is required meaning the shot will not be over exposed. This is one way to balance out the change in the aperture opening.

Likewise, with the larger aperture, if I don’t change the film speed but speed up the shutter instead, ultimately the same amount of light will pass as in the original settings and the picture will still be properly exposed.

There are three main variables in digital photography. These are the three variables I will be working with throughout the pages on my site that deal with camera settings in digital photography and how to get what you want from your pictures.

Everything else is as it correlates to these three variables.

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