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Tutorial

ISO Explained

By Marcus ReidUpdated September 12, 2026

[Demo data — development only. Specifications are illustrative; editorial copy is sample content.]

ISO controls how sensitive your camera is to light. Low ISO (100) produces the cleanest files; high ISO (6400+) brightens the image but introduces noise.

When to raise ISO

Raise ISO only after you've opened the aperture and slowed the shutter as far as you can. Modern cameras handle high ISO far better than older ones.

M

Written by

Marcus Reid

Staff Writer

Marcus writes about technique, education and the business of photography.

Last reviewed Jan 2025. Corrections policy.

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