katydid...learn about ISO.

Ok, so I'm a few days late.

Anywho...

Bryan Peterson had a great analogy. ISO is like a worker bee. So, if your ISO is 100, then you have 100 worker bees. And, if you move your ISO up to 200, you then have 200 worker bees. Thus, for a given aperture (shutter speed), the higher the ISO the faster your shutter speed (smaller aperature). Put another way, higher ISO is more sensitive which is why you often need higher ISO for low light situations and lower ISO for bright, daylight situations.

Good to know, right?!

The exercise was changing the ISO, keeping the aperature constant & seeing what happened to the shutter speed. Here are the results (my model for the exercise is my ficus bonsai, Newton The Fig Tree):

ISO ___, aperature, shutter speed

ISO 100, f/3.2, 1/2

ISO 200, f/3.2, 1/4

ISO 400, f/3.2, 1/8

ISO 800, f/3.2, 1/15

ISO 1600, f/3.2, 1/30

Notice that the pictures are exposed almost exactly the same. Also notice that the higher the ISO (especially on the ISO 1600), the nosier the picture. The noise is more apparent (to me) in the shadowy areas...the black isn't really black...sorta splotchy.

So, now I get ISO!