Photography Cheat Card
This card will give you a general idea of how your camera sees the image. The first row explains aperture.
What Is Aperture?
The main function of a camera lens is to collect light. The aperture of a lens is the diameter of the lens opening and is usually controlled by an iris. The larger the diameter of the aperture, the more light reaches the film / image sensor. Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture). A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras.
What is Shutter Speed?
Shutter speed or exposure time is the length of time a camera's shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time. Shutter speeds on the left-hand of the scale are for "stop-action" or sports. Right-hand side ISO can be used for that milky effect used with waterfalls or to show motion.
Next: Row three explains film speed or ISO
What is ISO?
In traditional (film) photography ISO (or ASA) was the indication of how sensitive a film was to light. It was measured in numbers (you’ve probably seen them on films – 100, 200, 400, 800 etc). The lower the number the lower the sensitivity of the film and the finer the grain in the shots you’re taking.
In Digital Photography ISO measures the sensitivity of the image sensor. The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain.
Higher ISO settings are generally used in darker situations to get faster shutter speeds. For example an indoor sports event when you want to freeze the action in lower light. However the higher the ISO you choose the noisier shots you will get.
Ever wondered what "F Stops" were or why aperture numbers are SMALLER when the lens is BIGGER?
| APERTURE, SHUTTER SPEED, ISO, OH MY!
A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras. Next: Row two explains Shutter Speed.