Type of extender: AF availability: EXTENDER EF 1.4x: When any of the extenders shown to the left are mounted on a lens with a maximum aperture darker than F4, AF cannot be used. EXTENDER EF 1.4x II: EXTENDER EF 1.4x III: EXTENDER EF 2x: When any of the extenders shown to the left are mounted on a lens with a maximum aperture darker than F2.8 The extender comes with a compatibility chart which essentially lists all of Canon's posher telephoto primes and zooms from 135mm f/2 up. Extenders also multiply the f-stop. The 135mm f/2 becomes a 270mm f/4, the 70-200mm f/4 becomes a 140-400mm f/8. RF Extender 1.4x does not fit. 07-22-2023 04:56 PM. I just bought a RF extender 1.4x and 100-500mm lens for my Canon R5. I have owned 2x extenders in the past and never had an issue with mounting it or any lens. Just tried to mount the new extender, didn’t think much about it and just mounted as usual. Turns out it won’t mount properly and EOS-1Ds Mark III: EOS-1D Mark III: EF 14mm f/2.8L USM: You can also correct RAW images taken with the compatible lens even when the extender is attached. * Can be used as a Manual Focus Only tool with compatible lenses. * Sharper than the EF 2x III extender (which is slightly softer). * Lightweight and easily carried. * Matches the stark-White tone of the newer white Canon L-Series lenses. * Extremely well built. * More robust (more lock-down assembly screws!) than previous versions. Currently, this teleconverter can be picked up for around £275, which isn’t quite bargain-basement territory, but is still less expensive than Canon’s EF Extender 2x III, which costs £300 Since some of the optics of the Canon 1.4X and 2X extenders extend into the back of the lens attached to them, they are only compatible with specific lenses. No EF-S lenses are compatible with any version of the Canon Extenders. Here is a link to the list of Canon lenses compatible with Canon extenders. Note that the only lenses with focal wrote: The Canon EF 70-300mm DO USM manual says it will not work with the EF 2X II extender. Will it work (particularly the IS) with the newer EF 2X III extender? thanks Jerry No, it will most likely not be fully compatible with that lens. Check the compatibility chart. aTWl.

canon extender ef 2x iii compatibility chart