Guides
Plain-English help for the optics behind your photos — what actually controls how much is in focus, how aperture, shutter and ISO trade against each other, and how to keep stars sharp at night. Each guide links to the calculator that does the math.
Focus
Understanding depth of field
What controls the in-focus zone — aperture, focal length, distance and sensor size — and how to use it.
Read the guide →
Exposure
The exposure triangle, explained
Aperture, shutter speed and ISO — what each trades away, and how stops let you swap between them.
Read the guide →
Astrophotography
How to shoot the night sky
The 500 rule, the stricter 300 rule, and the settings that keep the Milky Way sharp.
Read the guide →