Canon Extender EF 1.4X III

The Canon Extender EF 1.4X III is a teleconverter designed for Canon EF-mount cameras, extending the effective focal length of compatible Canon L-series super-telephoto lenses by 1.4x to give photographers additional reach for wildlife, sports, and distant subject photography without purchasing a longer lens. As part of Canon’s III-generation extender lineup, it offers improved optical performance and weather sealing compared to earlier Extender EF 1.4X versions.

The extender mounts between the camera body and a compatible super-telephoto lens, optically extending the attached lens’s focal length by 1.4x, for example turning a 300mm lens into an effective 420mm, or a 100-400mm zoom into an effective 140-560mm. This offers a cost-effective way to extend reach using lenses already in a photographer’s kit rather than investing in a dedicated longer super-telephoto optic. As with any teleconverter, using this accessory results in light loss, in this case one stop, meaning the effective maximum aperture of the attached lens is reduced accordingly, for example an f/4 lens becomes effective f/5.6 once the extender is attached, a notably smaller tradeoff than the two-stop loss of Canon’s 2x extenders.

The Extender EF 1.4X III is compatible only with a specific range of Canon L-series super-telephoto and telephoto zoom lenses designed to accept extenders, since the extender’s rear-mounted lens elements protrude into the lens mount in a way that isn’t compatible with standard lenses; photographers should confirm this extender’s compatibility with their specific lens before use. When paired with a compatible lens and a supporting Canon camera body, the extender maintains autofocus functionality, with a smaller impact on AF speed and accuracy than the 2x version, since the smaller magnification factor results in less light loss and a smaller effective aperture change.

Build quality includes weather-resistant sealing consistent with Canon’s L-series optics, along with a durable construction intended to withstand the demands of professional wildlife and sports shooting. The optical design was refined in this III generation to improve sharpness and reduce aberrations compared to the earlier Extender EF 1.4X II, helping minimize the image quality tradeoff that a teleconverter can otherwise introduce compared to shooting with the lens alone.

Key Features
– 1.4x teleconverter for compatible Canon EF-mount L-series super-telephoto lenses
– Extends effective focal length of attached lens by 1.4x
– One-stop light loss (e.g., f/4 becomes effective f/5.6)
– Weather-resistant sealing
– Maintains autofocus with compatible lenses and camera bodies
– Compatible only with extender-compatible Canon L-series lenses (confirm specific lens compatibility)