Canon 1.4x EF Extender II (Teleconverter)

The Canon 1.4x EF Extender II (Teleconverter) is a high-performance teleconverter designed for use with compatible Canon EF-mount telephoto lenses on Canon EOS digital and 35mm film camera systems, multiplying the attached lens’s effective focal length by 1.4x while preserving the lens’s original image quality. It’s compatible with fixed focal length lenses of 135mm or longer (except the 135mm f/2.8 Softfocus lens), along with select zooms including the EF 70-200mm f/2.8L, 70-200mm f/2.8L IS, 70-200mm f/4L, 70-200mm f/4L IS USM, and 100-400mm f/4.5-5.6L IS.

Optically, the extender is built from 5 elements in 4 groups with multicoated optics, maintaining sharpness nearly equivalent to the host lens on its own. Attaching the extender reduces effective aperture by one full stop, for example turning a 300mm f/2.8 lens into an effective 420mm f/4, or a 70-200mm f/2.8 into an effective 98-280mm f/4. The extender automatically calculates the resulting working aperture and transmits that information to the camera body for accurate exposure, viewfinder display, and EXIF data recording.

Autofocus remains possible on any EOS camera body when the combined lens-and-extender aperture is f/4 or faster, since this extender contains no autofocus motor of its own, relying instead on the attached lens’s AF system. On camera bodies with multiple focus points, only the center AF point remains active once the extender is attached. This Mark II version carries over the optical design of the original 1.4x Extender while adding enhanced weather-resistant construction, with a rubber gasket seal around the mount, along with improved anti-reflective coatings in the barrel for better performance in backlit conditions.

Build quality is compact, measuring approximately 2.9 in. (72.8mm) in diameter and 1.1 in. (27.2mm) in length, and weighing approximately 7.8-8 oz. (220g). The extender is not designed for use with lenses wider than 50mm, such as standard zoom lenses, and functions best with longer telephoto optics.

Key Features
– 1.4x teleconverter for compatible Canon EF-mount telephoto lenses
– Compatible with fixed 135mm+ focal lengths and select L-series zooms (70-200mm f/2.8L, 70-200mm f/2.8L IS, 70-200mm f/4L, 70-200mm f/4L IS USM, 100-400mm f/4.5-5.6L IS)
– 5 elements in 4 groups, multicoated optics
– One-stop light loss when attached
– Automatic exposure/aperture compensation (metering, viewfinder, EXIF)
– Autofocus supported with host lens apertures of f/4 or faster
– Only center AF point active when attached (multi-point AF cameras)
– Enhanced weather-resistant construction with rubber gasket seal
– Improved anti-reflective internal coatings
– Not recommended for lenses wider than 50mm
– Approximate weight: 220g
– Compatible with Canon EF-mount DSLR and 35mm film cameras