ISO – a Beginners Guide
ISO – How it Works
This photo was taken at a high ISO, notice the grain in the detail.
Some times when we are taking photos we find ourselves in a low light situation where we cant get a fast enough shutter speed to get a sharp photo. You could try opening your aperture to alow more light in, or you could use a flash, but some times thats just not prefered.
One option we have to achieve a faster shutter speed is to increase the cameras ISO sensitivity.
What is ISO
The ISO sensitivity determins how sensetive the cameras sensor is to light. At a high ISO setting like 1600 the cameras sensor becomes more sensitive to light and thus does not need to be exposed to light as long.
You may remember when we used to shoot with film, there was certain film made for sports. What made that film ideal for sports was that it had a higher ISO sensitivity such as 400, so it could achive a faster shutter speed then normal film that might have a lower ISO such as 100.
The Negatives of High ISO
There are some negatives to using a higher ISO though. The higher you boost your ISO the more distortion or grain you can see in your images, sometimes this can be a good look but usualy you want to avoid this distortion. The distortion you get from high ISO is kind of similar to a radio, at a low volume the radios music sounds fine, but as you begin to turn it up louder you begin to hear distortion and imperfections in the audio. As you boost the ISO sensetivity you begin to notice distortion.
Now days alot of the newer, higher end digital SLRs have amazing ISO sensitivities that barely show any distortion or grain.
ISO 200
ISO 1600
ISO 200 Close Up
ISO 1600 Close Up
Suggestions
You should always strive to use the lowest possible ISO sensitivity to achive the best quality photos, here are some guide lines of what ISO to use in certain situations.
Bright Sunny Day, you will want to use your lowest ISO either 100 or 200
Overcast cloudy day, ISO 400 would be a good bet for an overcast day
Indoors low light, you would want to use an ISO between 400 and 800
Night Time, You can boost your ISO up to 1600 or 3200 but at this point you might want to look into using a tripod and a longer shutter speed to avoid harsh grain.
