Understanding ISO: try it yourself

1. ISO Ladder

In a dim room, take photos at ISO 100, 400, 1600, 6400; compare noise.

2. Noise Hunt

Zoom in on each ISO test photo; find where grain appears.

3. Low-Light ISO

Photograph a book page in dim light at different ISOs; find the lowest usable one.

4. ISO + Shutter Link

Increase ISO; watch how shutter speed changes in auto/semi-auto mode.