From what I've seen and read, this lens is really just a 150-400mm lens. 400 and beyond is soft and the Canon 400mm 5.6 upsized to 600 and even 700mm is sharper at the Tamron's native 600mm setting! For me personally I'd get the Canon 400mm. And I plan to eventually.06-28-2016 11:47 PM. This lens WILL work with a Canon tele-extender if you do this. (An old trick given to me by an old timer at Canon headquarters). Use a very small piece of tape (preferrably the blue tape used to mask painting on walls) and cut an approx. 3mm by 2mm piece with an exacto knife and stick it to the lens contacts in the back. The RF 70-200 f2.8 or f4 is not compatible with the 1.4 or 2.0x extenders. Your current choices would be: RF 100-300mm f/2.8 L IS USM - TC's can be used with full focal length 100-300. RF100-400mm F5.6-8 IS USM - TC's can be used with full focal length 100-400. RF100-500mm F4.5-7.1 L IS USM - TC's can be used 300-500mm only. RF400mm F2.8 L IS USM. Options. 05-13-2023 06:35 PM. I did some testing today comparing the Sigma 150-600 C to the RF100-500 +1.4x extender. With both lenses zoomed all the way (600mm and 700mm respectively). I set the Sigma lens at F/8 and the Canon at F/10, at 1/1000. I adjusted the ISO to compensate for the Canon's smaller aperture.
Physical differences. Since the introduction of the 800mm f5.6, Canon changed their off-white color of their telephoto lenses. All the new MKII IS super-tele lenses from Canon feature this new coloring so the MKIII extenders have been updated to match both the color and also the very slightly smoother design aesthetic of these lenses.
The Canon 1.4X EF Extender is a professional grade teleconverter designed exclusively for use with select Canon brand L-Series lenses (focal lengths over 135mm). Increasing the lens focal length by a factor of 1.4 times, Extender EF 1.4X incorporates incorporates careful lens placement and anti-reflective coatings for high quality optical EF 28-90mm f/4-5.6 II : EF 28-90mm f/4-5.6 III : You can also correct RAW images taken with the compatible lens even when the extender is attached. I'd suggest getting the 1.4II. The difference between the II and III is quite small as other's have pointed out and you'll be saving a fair amount of money especially if you pickup one a used one. The 2xIII works nicely on the 70-200II however focusing speed is reduced by 50% so be aware of that. The new mount converter enhancing the extensibility of the L-Mount system. The SIGMA MOUNT CONVERTER MC-21 allows SIGMA SA mount and SIGMA’s CANON EF mount interchangeable lens owners to use their lens investment on L-Mount camera bodies. The converter allows more freedom of choice for L-Mount cameras, enhancing the extensibility of the L So the Canon 1.4x EF Extender would make a 200mm focal length more like 280mm. While there can be some image degradation, this does allow for a relatively cheap way to achieve the magnification found in longer focal lengths. An extender is also lighter and smaller than a lens, coming in at only 2.9″ x 1.1″, 7.8 oz. (72.8 x 27.2mm, 220g).