A reference for the symbols, not the predictions
Photography planning tools
Astrian Light
Depth of field, ND filters, timelapse, star trails, field of view, and more. Transparent formulas — learn while you calculate.
Maximum exposure for pinpoint stars. The 500 Rule is quick; NPF is pixel-precise.
500 Rule
20.8s
500 ÷ (24 × 1) = 20.8s
NPF Rule (precise)
4.9s
NPF(f/2.8, 24mm, 5µm)
NPF is 16s more conservative. Use NPF for max detail.
Most calculator apps show you a number. We show you the math. Understanding depth of field, the NPF rule, or ND filter stops makes you a better photographer — not just someone pressing buttons.
All calculations run entirely in your browser. No data is sent to any server. The camera database includes 200+ models with verified sensor specifications from manufacturer data sheets and openMVG calibration datasets.
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Built independently, no external funding. If these tools help your photography, consider supporting the project.
Support on Ko-fi (opens in new tab)Astrian Light is in development. If you notice something that doesn't work as expected, we'd appreciate hearing about it at hello@astrian.app.
Astrian is in development. If you notice something that doesn't work as expected, we'd appreciate hearing about it at hello@astrian.app.