The 2x Extender III has some useful implications in macro work, offering an extra 100% magnification without sacrificing the minimum close-focusing distance; in the case of the 200mm ƒ/2.8L II Guide to Canon EF extenders. 1.4x and 2x teleconverters. Differences between models and lens compatability Canon Extender EF 1.4x III: 12/2010: 3: 7: 72.0 x 27.2 Canon has the RF 1.4x and RF 2x. I would guess that they are compatible with all L series telephoto lenses for the RF mount. I purchased a Canon Extender EF 2X III but it does not fit the lens. Stack Exchange Network Stack Exchange network consists of 183 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. This lens is only compatible with fixed focal length L-series lenses 135mm and over, as well as the EF 70-200/2.8L, EF 70-200/2.8L IS, EF 70-200/4L, and EF 100-400/4.5-5.6L. Additionally, please see the lens and/or camera body manual for full compatibility information with the Extender EF 2X III. Maintains Metering, Autofocus, and IS. Dust and Water Resistant. Extend the reach of select Canon RF-mount lenses with the Extender RF 2x. This teleconverter magnifies the image by 2x and retains full communication between the lens and camera body, enabling metering, autofocus, and image stabilization as well as the transmission of Exif data. Caution. Do not attach two or more Extenders on the same camera. Doing so will degrade the optical performance and the camera will not be able to obtain proper exposure readings. To enhance water and dust resistance, the Extender EF1.4X III and EF2X III have a rubber ring around the mount. LP811. ¹ Lenses with dust/moisture resistance are fitted with a rubber ring on the lens mount which may cause sligth abrasion of the camera mount. This in no way affects either the lens or camera performance. Can we help you choose your next lens?Our lens selector will take you through our range of lenses and help you find the perfect match Enjoy more zoom on your existing lenses by choosing a Canon extender lens to add to your kit. RF Extender 2x EF Extender 1.4x III It is fully compatible with the Extender EF 1.4x II and 2x II teleconverters. Although the 200mm focal length is short for general wildlife use, it can still deliver great image quality with an extender mounted behind it. Buy Canon EF 70-200mm f/4L IS USM Lens at Amazon, B&H, Adorama. 7. Canon EF 70-200mm f/4L USM Lens PJM5I.