Which rule should I trust for pinpoint stars — the 500 Rule or the NPF Rule?

The NPF Rule is stricter and accounts for aperture and sensor resolution, so it's the more reliable choice on modern high-resolution sensors, even though the simpler 500 Rule is easier to calculate in the field.

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Star Trails Max Shutter Guide for Landscape Photography

A landscape night shot aiming for pinpoint stars — rather than deliberate star trails — needs to stay under a maximum shutter speed that depends on focal length, and this guide works out exactly where that line sits.

Star Trails Max Shutter Guide for Landscape Photography

Open the Star Trails Max Shutter Guide

Recommended settings

Wide-angle landscape astro (14-24mm): the 500 Rule typically allows 20-35 seconds before trailing becomes visible.
For a stricter, pixel-level check, the NPF Rule accounts for aperture and sensor resolution too, usually landing tighter than the 500 Rule.

Tips for this niche

If deliberate star trails are the goal instead, ignore this guide's limits and shoot well past them, or stack multiple exposures.
A wider lens allows a longer shutter speed before trailing than a longer one — check the guide again if switching lenses mid-shoot.

Got your Landscape settings dialed in?

Turn your landscape shoot into ready-to-post captions, hashtags and matching audio — free to try, no signup.

Want the full lesson?

This topic is covered in depth in Lesson 8: Landscape & Travel Photography.

Example scenario

Shooting at 20mm on a full-frame body, the 500 Rule suggests roughly 25 seconds is safe, while the more conservative NPF Rule — accounting for aperture and pixel density — recommends closer to 15 seconds for genuinely pinpoint stars at full resolution.

Common mistakes

Using the 500 Rule on a high-resolution modern sensor without adjustment. the 500 Rule was designed for older, lower-resolution sensors — the stricter 400 Rule or NPF Rule usually gives a more accurate limit for current cameras.
Not re-checking after a focal length change. switching from a 14mm to a 24mm lens meaningfully shortens the maximum shutter speed before trailing — recalculate rather than reusing the wider lens's number.

FAQ

Which rule should I trust for pinpoint stars — the 500 Rule or the NPF Rule?: The NPF Rule is stricter and accounts for aperture and sensor resolution, so it's the more reliable choice on modern high-resolution sensors, even though the simpler 500 Rule is easier to calculate in the field.

Guides for this tool, by niche

Star Trails Max Shutter Guide for Travel Photography

Troubleshooting

Why Are My Star Photos Trailing Instead of Sharp?