The mount decides before the specs do
A teleconverter is a dedicated optical accessory, and both the Canon Extender RF and the Sony FE 1.4X Teleconverter are built for specific mirrorless systems. The Canon unit fits select Canon RF-mount lenses, while the Sony unit fits select Sony E-mount lenses. You cannot cross-mount them, so the first question is not which one is better—it is which camera system you shoot.
If you already own a Canon RF body, the Sony teleconverter is not an option, and vice versa. This comparison focuses on what each teleconverter offers within its own system, so you can judge whether it makes sense for your lenses and shooting style.
What each teleconverter does
- Sony FE 1.4X Teleconverter for Select Lenses: Sony FE 1.4X Teleconverter increases the lens's magnification by 1.4x for a narrower field of view. A 1.4x multiplier extends reach without the larger 2x magnification, which can help balance framing and light.
Sony FE 1.4X Teleconverter for Select Lenses - Canon Extender RF: Canon Extender RF magnifies the image by 1.4x and retains full communication between the lens and camera body, enabling metering, autofocus, and image stabilization as well as the transmission of Exif data. Full communication means you keep automatic exposure, autofocus, and stabilization, plus metadata for your files.
Canon Extender RF
Compatible lenses: the lists are short and specific
- Sony FE 1.4X Teleconverter: Compatible lenses listed in the supplied record: FE 70-200mm f/2.8 GM OSS, FE 100-400mm f/4.5-5.6 GM OSS, FE 200-600mm f/5.6-6.3 G OSS, FE 400mm f/2.8 GM OSS, and FE 600mm f/4 GM OSS. Only these are confirmed for this teleconverter in the supplied information.
- Canon Extender RF: Compatible lenses listed in the supplied record: RF 600mm f/11 IS STM and RF 800mm f/11 IS STM. The RF 100-500mm f/4.5-7.1L IS USM can only be used within the 300-500mm range. Other RF lenses are not confirmed as compatible by the supplied information.
The RF 100-500mm restriction matters
The Canon Extender RF works with the RF 100-500mm f/4.5-7.1L IS USM only between 300mm and 500mm. That means you cannot use the full zoom range with the extender attached. If you often shoot at the wide end of that lens, the extender will force you to zoom in or remove it. The supplied information does not explain why this restriction exists, but it is a clear operational limit to plan around.
Communication and stabilization
- Sony FE 1.4X Teleconverter for Select Lenses: The dedicated design maintains full communication between the lens and E-mount mirrorless cameras, including auto-exposure metering, autofocus, and Optical SteadyShot image stabilization. You keep autofocus and stabilization with compatible Sony lenses, which is important for handheld telephoto work.
- Canon Extender RF: The Extender RF retains full communication between the lens and camera body, enabling metering, autofocus, and image stabilization as well as the transmission of Exif data. Canon users keep the same core functions and gain EXIF data for easier cataloging and post-processing.
Durability and handling
Both teleconverters are designed for challenging conditions. The Sony FE 1.4X Teleconverter has a dust- and moisture-resistant construction that matches the lens, according to the supplied information. The Canon Extender RF is dust and water resistant and adds a heat shield exterior to help performance in a range of conditions. Neither record includes care instructions, so follow the lens and camera manufacturer's guidance for cleaning and moisture exposure.
Aperture loss: what the supplied information does not say
A 1.4x teleconverter reduces the amount of light reaching the sensor, but the exact aperture loss is not stated in the supplied records for either product. In general photography terms, a 1.4x multiplier costs about one stop of light, but you should confirm the specific effect for your lens and camera combination in the manufacturer's documentation. The records here confirm that auto-exposure metering is maintained, but they do not list resulting f-numbers or autofocus limits.
Which one fits your kit?
- Choose the Sony FE 1.4X Teleconverter if:: You shoot Sony E-mount and own one of the compatible lenses listed above, especially if you want to extend reach while keeping autofocus and Optical SteadyShot.
- Choose the Canon Extender RF if:: You shoot Canon RF and own the RF 600mm f/11 IS STM, RF 800mm f/11 IS STM, or the RF 100-500mm f/4.5-7.1L IS USM and can live with the 300-500mm restriction on that zoom.
- Look elsewhere if:: Your lens is not on the compatibility list for your system. The supplied information does not confirm support for other lenses, and using an incompatible lens may not be possible or may not retain full communication.
The honest tradeoff
Both teleconverters add reach and keep electronic communication with compatible lenses, but they also add an optical element between lens and camera, which can affect image quality and light transmission. The supplied records do not include MTF charts or light-loss figures, so we cannot quantify those effects here. The bigger practical tradeoff is compatibility: each teleconverter works with a short list of lenses, and the Canon option has a zoom-range restriction with the 100-500mm. Check your lens against the lists above before you buy.
