Кто мне обьяснит, в чем разница между DC motor и USM? Не в теории, это я и так прочитал, на практике?
EF 75-300mm f/4-5.6 III
Estimated Retail Price: $199.99
The optical system, construction, and exterior are the same as the EF 75-300 mm f/4-5.6 III USM’s. The difference is that it uses a DC motor instead of a USM to drive the AF.
EF 75-300mm f/4-5.6 III USM
Estimated Retail Price: $234.99
The newly developed Micro USM makes autofocusing quicker and quieter. The improved zoom mechanism also makes zooming smoother.