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 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 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 Compatible lens chart (Last Update Date：Decembar 14 2023) Please make selections below. 150-500mm F/5-6.7 Di III VC VXD (Model A057) Product Page. Di III Lenses. EF1.4X III: EF2X III: EF 135mm f/2L USM: 189mm f/2.8: 270mm f/4: EF 180mm f/3.5L Macro USM: 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 Mount Adapter EF-EOS R question about compatibility with Extender EF 1.4x III in Camera Accessories 11-14-2023; Interesting EF 400 f2.8 IS II issue - EOS-1D X Mark III rendered unresponsive in EF & RF Lenses 11-12-2023; EF 100-400mm f/4.5-5.6L IS II USM Lens switches to MF mid shoot in EF & RF Lenses 11-10-2023 The Canon EF 100-400mm f/4.5-5.6L IS II USM Lens is compatible with the Canon EF 1.4x III and EF 2x III Extenders. As is often the case, the focal length range of the with-extenders combinations is quite impressive with relatively little increase in size and weight. Extender EF 1.4x III – 72 x 27.2 225 Extender Cap E II – LP811 – – – – – – Extender EF –2x III 72 x 52.7 325 Extender Cap E II – LP811 – – – – – – EF ZOOM LENSES EF 8–15mm f/4L Fisheye USM Filter Holder 78.5 x 83 540 Lens Cap 8‐15 EW‐77 (15mm only LP1219 – – – ‐ – EOS R7 Comparing RF lenses at similar focal lengths in EF & RF Lenses 11-16-2023; 35mm f2 usm vs 35mm f1.4L? in EF & RF Lenses 11-16-2023; Mount Adapter EF-EOS R question about compatibility with Extender EF 1.4x III in Camera Accessories 11-14-2023; Interesting EF 400 f2.8 IS II issue - EOS-1D X Mark III rendered unresponsive in EF & RF Lenses 4ynI.