Monday, May 16, 2011

Basic Camera Guide - ISO or ASA

I have decided to try and do more with my blog than just show my work. I am going to try and write some pieces that will focus on teaching a little bit about photography which will mostly be geared more toward new photographers.

My first learning guide is going to be about ISO or ASA. These are traditional terms left over from film that has translated into the digital age. ISO and ASA are interchangeable terms that mean the same thing. ISO is the name referred to by the International Organization for Standardization. ASA is the American Standards Association term. Both have been used in the past a fair amount. As the world community has become much more connected the term ISO has become the dominant term in the digital age. These terms used to represent the speed of film. A higher film speed translates into less light needed to create an image. The down side of this is that a higher film speed also means a loss of quality. Speeds are pretty much listed as a doubling effect. Many digital cameras can shoot with film speeds as low as 100 or even lower. As the film speed becomes faster the number doubles, 200, 400, 800, 1600,... and so on.

Probably the most common speed known is 400. Most film bought at a store is 400 speed. It is a pretty average film. It is okay in low light and okay in bright light without losing much quality. Sometimes though I have seen disposable cameras with a speed of 800. A 200 speed film with be higher quality but require more light. When shooting with flash or on a bright sunny day it will work well and give you a crisper image than if shooting 800. shooting at 1600 though will allow you to shoot in less light but you will get pixelation and loss of quality.

I hope this will help you to better understand what ISO or ASA is. Later I will be doing another post that will tell you more about how to use ISO in conjunction with shutter speed and aperture size to create a better image. If you have an questions or comments leave them in the box below. Let me know what you think of the article and tell me about your experiences with ISO.

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