The following chart was prepared for use as a field guide for Challenge 62.
To use it, find the ISO you with to use and go down that column until you're on the row of the aperture you wish to use. The value in that cell is the fastest permissible shutter speed for the low light portion of the challenge.
Alternatively, you can use the simple f/16 rule. Set your camera to ISO 1600, aperture priority, and set the aperture to f/16. Point the camera at the scene and check the shutter speed indicated by the camera. If the shutter speed with no exposure compensation is 1 second or longer, then the scene is dark enough for the challenge.
| 100 | 200 | 400 | 800 | 1600 | 3200 | |
|---|---|---|---|---|---|---|
| f/1.2 | 1/11 | 1/22 | 1/44 | 1/89 | 1/178 | 1/356 |
| f/1.4 | 1/8 | 1/16 | 1/33 | 1/65 | 1/131 | 1/261 |
| f/1.8 | 1/5 | 1/10 | 1/20 | 1/40 | 1/79 | 1/158 |
| f/2 | 1/4 | 1/8 | 1/16 | 1/32 | 1/64 | 1/128 |
| f/2.8 | 1/2 | 1/4 | 1/8 | 1/16 | 1/33 | 1/65 |
| f/4 | 1s | 1/2 | 1/4 | 1/8 | 1/16 | 1/32 |
| f/5.6 | 2s | 1s | 1/2 | 1/4 | 1/8 | 1/16 |
| f/8 | 4s | 2s | 1s | 1/2 | 1/4 | 1/8 |
| f/11 | 8s | 4s | 2s | 1s | 1/2 | 1/4 |
| f/16 | 16s | 8s | 4s | 2s | 1s | 1/2 |
| f/22 | 30s | 15s | 8s | 4s | 2s | 1s |
| f/32 | 64s | 32s | 16s | 8s | 4s | 2s |