Reply #2: Yes, increasing the ISO makes your camera "faster".

[bvar22]

The balance is still between the Shutter Speed and the Aperture (F Stop).
There is some sacrifice in raising the ISO. In general, Grain increases, Noise increases, and the color saturation decreases.

I would prefer to shoot at ISO 100 all the time, but to get a Shutter Speed of 1/500 at ISO100, I would have had to open the apreture (a lower F Stop). Opening the aperture decreases the depth of field (how much of your pic is "in focus"). It was difficult to keep these fluttering bugs in focus, so I opted for greater Depth of Field (Focus)(margin of focus error) by using F/8 and raising the ISO to 500.

1/500 shutter speed is still pretty slow for things with wings, but this was about the best compromise I could find.