Sharp Stars with Rule of 500 Calculator
Astrophotography fights against the rotation of the Earth. The **Rule of 500** tool at **Online Tool Base** calculates the maximum shutter speed you can use before stars turn from pinpoint dots into blurry trails. It is the gold standard formula for Milky Way photography.
The math is: `500 / (Focal Length * Crop Factor)`. **onlinetoolbase.online** automates this, letting you input your lens (e.g., 14mm) and sensor type to get the safe exposure time (e.g., 35 seconds). It helps you capture crisp, bright night skies.
Why Use This Tool?
If you expose for too long, the earth moves enough that stars stretch. If you expose too short, the image is noisy. This tool finds the sweet spot. It even offers the stricter "NPF Rule" or "Rule of 400" for high-megapixel cameras that reveal trails sooner.
Key Features
- Sensor Sizing: Micro 4/3, APS-C, Full Frame.
- Strictness: Choose Rule of 500 (Easy) or Rule of 400 (Sharp).
- Declination: accounts for shooting North vs South (advanced).
How to Use
- Select your Camera Sensor.
- Enter Lens Focal Length (mm).
- Read the Max Shutter Speed.
- Set your camera and shoot the stars.
Technical & Privacy Note
Astrophotography aid. The **Rule of 500 Calculator** from **Online Tool Base** functions offline. No location data is used.