What does SLR STM mean?

STM is the abbreviation of stepping motor, which can focus automatically when shooting video continuously. The focusing speed of STM motor is between traditional motor and USM, which is not fast, but as quiet as USM.

The main function of STM is to read and focus continuously when shooting video. Previously, the lens had to be focused manually when shooting video. But the lens of STM motor can focus automatically when shooting video. Of course, this function depends on your body. So far, only 650D has the auto-focus function for shooting video.

Extended data:

superiority

1, the rotation angle of the motor is proportional to the number of pulses;

2. When the motor stops, there is maximum torque (when the winding is excited);

3. Because the accuracy of each step is 3% to 5%, and the error of one step will not be accumulated to the next, it has good position accuracy and motion repeatability;

4. Excellent start-stop and reverse response;

5, because there is no brush, high reliability, so the life of the motor only depends on the life of the bearing;

6. The response of the motor is only determined by the digital input pulse, so open-loop control can be adopted, which makes the structure of the motor simpler and controls the cost.

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