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Originally Posted by enaberif Actually ISO is how much light the camera will let onto the sensor. |
that is not correct, but i understand what you are trying to say. the shutter is what lets the amount of light into the sensor, the ISO is the level of sensitivity to that light. further explanation in a second.
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Originally Posted by lcdguy The reason is that really high iso rates can cause noise to be shown on the picture as making the shot grainy. lower the iso to 100 and use a tripod. |
bingo. you want low ISO, especially at night, and long shutters for those effects. a tripod is an absolute must.
the reason noise (the technical term for what most refer to as grain) at high ISO shows up is because the image signal is being amplified which also amplifies the noise. noise is always there, but at low ISO we don't really notice it. this is how digital cameras achieve multiple ISO levels...they raise or lower the sensivity to light by increasing or decreasing the amplification of the image the sensor sees. hope that makes sense.
for guys like me shooting sports in a gym with poor lighting and no strobes, we need high ISO in order to maintain 1/500 shutters. noise is just something that is inevitable in that case, and for news print or the like, it doesn't even show up. that is what made the 20D back in the day the king of sports shooting, even better than the original 1D...it had the least amount of noise at ISO1600. nowadays a dozen other cameras perform better at high ISO but the 20D was the original low light sports shooting bad boy on the digital camera market