Canon EF 17-40mm f/4L USM Lens

Lens - zoom lens for Canon Digital SLR cameras, for Fullframe and APS-C, 77mm, lens alignment Canon EF, 77mm diameter filter, USM actuator This excellent zoom lens designed for Canon digital SLR and film cameras offers a wide angle view and focus from as low as 28cm. Its high ...Lens - zoom lens for Canon Digital SLR cameras, for Fullframe and APS-C, 77mm, lens alignment Canon EF, 77mm diameter filter, USM actuator This excellent zoom lens designed for Canon digital SLR and film cameras offers a wide angle view and focus from as low as 28cm. Its high moisture and dust resistance makes it suitable for everyday use.The lens combines three aspheric elements along with super UD.

Another perk is the possibility to attach a filter with a diameter of 77mm that can be screwed on or attached by a drop-in gelatine-filter holder that can be found at the back of the lens. The Canon EMD (electromagnetic aperture control) comes as another advantage of the lens. The focusing process of the lens is extremely quick and quiet due the USM actuator.This actuator uses the piezoelectric principle and is formed by two rings placed against each other, one of which acts as a stator, the second (actuating the focusing...