ISO Explained: When to Raise It (And Why It Adds Noise)
DefinitionHow sensitive your camera sensor is to light.
1The Simple Explanation
ISO is like the volume knob on an amplifier. If the signal (light) is weak, you turn up the ISO. But just like an amp, turning it up too high adds static (noise).
2Technical Deep Dive
Base ISO (usually 100) has the highest dynamic range. Raising ISO amplifies the analog signal from the photodiode before digitization, or digital gain after.
Common Misconceptions
Myth: High ISO is always bad. Fact: A sharp grainy photo is better than a blurry smooth photo. Don't be afraid to raise ISO if you need the shutter speed.