Tutorials
SUMMARY
The reciprocal rule is a guideline for photographers to minimize blur from handheld camera shake by setting the minimum shutter speed to the reciprocal of the lens's focal length. For example, a 50mm lens requires at least a 1/50s shutter speed. This rule must be adjusted for crop sensor cameras by multiplying the focal length by the crop factor before determining the shutter speed. Modern high-resolution sensors can make the rule stricter, with some photographers doubling the recommended shutter speed to compensate for increased detail visibility. Image stabilization systems can also reduce the required minimum shutter speed, with each 'stop' of stabilization halving the necessary speed.
TAKEAWAYS
The reciprocal rule sets minimum shutter speed to 1/focal length to avoid blur.
Crop sensor cameras require adjusting the rule by multiplying focal length by the crop factor.
High-resolution sensors may necessitate faster shutter speeds than the basic rule suggests.
Image stabilization allows for slower shutter speeds by compensating for camera shake.