Top features: - Versatile zoom range for photographing a range of subjects - Advanced Canon optics for brilliant results - Close focusing distance for detailed shots - Experiment with filters thanks to the non-rotating front element - Weather resistant design for use out in the fieldVersatile zoom rangeThe Canon EF 17-40 mm f/4L USM lens offers an ultra-wide angle zoom range on full-frame EOS cameras or acts as a standard zoom when mounted on DSLRs equipped with APS-C sized sensor - giving an angle of view equivalent to a 28-70mm lens.Advanced Canon opticsThe advanced Canon optics has been developed with 12 lens elements arranged in nine groups. The Super Spectra lens coating works to ensure outstanding colour balance with minimal ghosting and flare.With three aspheric elements, the Canon EF wide-angle lens provides stunning image quality over the 17-40mm zoom range, with the Super Ultra-low Dispersion glass working to prevent chromatic aberrations.Close focusing distanceA close focusing distance of just 28cm throughout the entire zoom range means you can achieve stunning close-up shots with beautiful background blur.The Canon EF 17-40mm lens has been constructed with an ultrasonic motor that drives a speedy focusing performance in near silence. The outstanding holding torque reaches the precise point of focusing, ensuring a consistently accurate performance.What's more, there is full-time manual override ready and available, allowing you to make focus adjustments without leaving AF mode.Experiment with filtersThe front of the lens is non-rotatable, this makes it easier to use specialised filters such as polarisers and colour graduates. There is a drop-in gelatine-filter holder located at the back of the EF lens.Weather resistantThe Canon lens boasts a lead-free glass construction, making it highly resistant to dust and moisture - ideal for taking photos in rough conditions and challenging environments.
