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- Canon EF 17-40mm f/4L USM Lens
The new and affordable L-series comes to life with the Canon EF 17-40mm f/4L USM, an ultra-wide-angle zoom lens that's perfect for both film and digital SLRs. Its Optical coatings are improved for use with digital cameras. High-class optics is guaranteed by the use of 3 Aspherical lens elements, an additional feature to a Super UD (Ultra-low Dispersion) glass element. The lens has a maximum aperture of 1:4 and 17 - 40mm focal length. Constructed to pro standards, it’s also highly resistant to dust and moisture. It has a ring type USM for silent and high-speed AF operation. It is compatible with APS-C and Full Frame Sensor DSLR Cameras.
Product Features in Detail
Ultra-wide or standard zoom
The EF 17-40mm f/4L USM acts as an ultra-wide angle zoom on film or full-frame digital EOS cameras. On DSLRs equipped with APS-C sized sensors it acts as a standard zoom, giving an angle of view equivalent to a 28-70mm lens on a full-frame camera.
Minimum focusing distance is just 28cm throughout the entire zoom range.
Superior optical performance
The EF17-40mm f/4L USM has 12 lens elements arranged in nine groups. Super Spectra coating ensures excellent colour balance and minimises ghosting and flare. To provide superb image quality over the complete 17-40mm zoom range the lens uses three aspheric elements. Super UD (Ultra-low Dispersion) glass prevents chromatic aberrations.
A ring-type ultrasonic motor drives autofocus extremely quickly, and in near silence. Excellent holding torque ensures the point of focus is reached accurately, without overshooting. Furthermore, full-time manual override is available, making it possible to adjust focus without leaving AF mode.
Non-rotating front element
The front of the lens does not rotate, which makes using specialised filters, such as polarisers and graduates, easier. A drop-in gelatine-filter holder can be found at the back of the lens.
Smooth background blur
A virtually circular aperture diaphragm gives out of focus regions a softer, more uniform feel. Sharp foreground objects stand out against a smooth blurred background.
Highly resistant to moisture and dust, the EF17-40mm f/4L USM is ideally suited for use in harsh environments. Environment friendly lead-free glass is used throughout its construction.
|Angle of view (horzntl, vertl, diagnl)||93° - 49°20', 70°30' - 34°, 104° - 57°30'|
|No. of diaphragm blades||7|
|Maximum magnification (x)||0.24 (at 35mm)|
|Filter diameter (mm)||77|
|Max. diameter x length (mm)||83.5 x 96.8|
|Magnification - Extension Tube EF12 II||0.83 - 0.32|
|Magnification - Extension Tube EF25 II||1.02 - 0.70¹|
|Focal Length & Maximum Aperture||17 - 40mm; 1:4|
|Lens Construction||12 elements in 9 groups|
|Diagonal Angle of View||104° - 57° 30'|
|Focus Adjustment||Inner focusing system with USM|
|Closest Focusing Distance||0.28m / 0.9 ft.|
|Zoom System||Rotating type|
|Lens Cap||E-77U / E-77II|
|Extenders EF1.4x II and EF2x II||Not compatible|