Shutter Speed Calculator

How to Use This Calculator

1. Enter your lens focal length in millimeters (found on the lens barrel).
2. Enter your camera\'s crop factor (1.0 for full-frame, 1.5-1.6 for APS-C, 2.0 for Micro Four Thirds).
3. Optionally, enter subject speed in mph to calculate shutter speed needed to freeze motion.
4. The calculator displays the minimum shutter speed based on the reciprocal rule and motion-freezing requirements.

Shutter Speed Formula

Minimum shutter speed to avoid camera shake is calculated using the reciprocal rule:

Example: A 100mm lens on a 1.5x crop sensor: Effective focal length = 150mm. Minimum shutter speed = 1/150s (use 1/160s or faster to be safe).

Full Description

Camera shake is one of the most common causes of blurry photos. The reciprocal rule provides a guideline for the minimum shutter speed needed to avoid shake when handholding your camera. This rule states that your shutter speed should be at least 1 divided by your effective focal length (accounting for crop factor).

However, the reciprocal rule only addresses camera shake—not subject motion. To freeze moving subjects, you need faster shutter speeds. The required speed depends on how fast the subject is moving and in what direction relative to the camera. Subjects moving toward or away from the camera need slower speeds than those moving across the frame.

This calculator helps you determine both the minimum shutter speed to avoid camera shake and the speed needed to freeze motion. Use it before shooting to set appropriate shutter speeds, or when reviewing why images might be blurry. Remember that image stabilization can allow slower speeds for camera shake, but won\'t help with subject motion.

Frequently Asked Questions