What is a safety shutter? How to calculate

Safety shutter means that the camera usually performs the exposure process at the moment when 1/30s or 1/60s camera clicks. If this time is longer than 1/60s, the picture will be blurred easily due to the shaking of hands. The safe shutter speed is the reciprocal of the focal length, that is, the safe shutter speed = 1/ focal length.

For example, if you are in Canon EOS? If a 50-mm lens is used for 30 days, then 1/80s is the safety shutter (because the focal length conversion coefficient of EOS 30D days is 1.6, the actual equivalent focal length of the 50-mm lens is 80mm). If the shutter speed of1125s or 1/250s is selected, the shooting stability can be guaranteed. On the other hand, if the shutter speed of 1/30s is selected, there may be "false shooting".

Shutter function

Generally speaking, the larger the shutter time range, the better. Low seconds is suitable for shooting moving objects, so a camera emphasizes that the shutter can reach116000 seconds at the earliest, which can easily capture fast moving targets. However, when shooting traffic at night, the shutter time will be lengthened, and the silky water flow effect in ordinary photos can only be photographed with a slow shutter.

As for the common B shutter function of SLR cameras, although you can freely decide the length of exposure time and have high shooting flexibility, most consumer digital cameras can't support it at present, and can provide the default values of slower speed such as 2 seconds, 8 seconds, 16 seconds at most.