Aperture, ISO and Shutter Speed 101

Light is everything in photography.

There are three things that affect the amount of light when a picture is taken. Below is some basic information everyone should know and understand about photography and picture taking.

1) Aperture- how big the hole is that lets the light in the camera.
2) ISO- "film sensitivity", the larger the number the more "sensitive" and the faster a shot will expose.
3) Shutter speed- how long the hole is open to let light in.

Besides affecting light each item affects other things so the best photos are a good combination of each.

Aperture

1) Aperture affects depth of field-how much of the picture is in focus. Think of a hose with water running out of it. By itself the water doesn't go very far. Similarly with a large aperture 1.4 a very shallow amount of the picture will be in focus. But if you cover the hole of a garden hose with your thumb, the water goes much much further. This is like a 5.6 or greater aperture. Much more of the picture will be in focus.

ISO

2) Traditional cameras had an "ISO of 100." This is the base. Today digital cameras can go as far as 6400. This is huge, but the higher the number the more grainy a picture will look, or the more visible grain you will see. Some people really like the grain others don't. The numbers double each setting so it goes 100, 200, 400, 800, 1600, 3200, etc.

Shutter Speed

3) Apart from the amount of time light can get in the camera, shutter speed also affects how much blur a photo has. For example The river shots you have seen where the water is all fuzzy and silky was exposed for a long period of time perhaps 5-30 seconds. It is easy and fun to do things like this. However if you are filming dancing or sports you want the person to be crisp and not blurry. This might mean that you need an exposure of 1/640th of a second. That is why the aperture can be so important.