The 1.4x TC drops the maximum aperture from f/4 to f/5.6, and the 2x TC drops it to f/8. The good news is that on your 7D the 1.4x TX gives you the angle-of-view equivalent to a focal length of nearly 450mm on a full frame camera, which is fine for a lot of wildlife shooting. Dan. I have the EF 70-200 f4L IS (v1) and using the 1.4x II it works ok but with 2X III it is only good with stationary object. Anything that requires faster AF is useless. As a result. I sold the TCs and bought a RF 100-400. Buying the RF 100-400 and add a RF TC wight be worthwhile if you can't swing for the RF 100-500. 5Ds + 70-200 f/2.8L IS II + 2ex III - 400mm f/5.6 ISO 640 + .5EV in post. I cropped away 60% of the pixels (from 50.6 down to 20.2 - a 3:2 aspect ratio with the same width would have been 13+ MP) and then downsized to 2048 pixels square. EDIT: uploading to Flickr and linking it appears to be a much better way to go than uploading to DPR. Extenders (Optional) With Extender EF 1.4X ll or EF 2X llattached, the lens specifications will change as follows: Item With EF1.4X ll Extender With EF2X ll Extender Focal length (mm) 98 – 280 140 – 400 Aperture f/4 – 45 f/5.6 – Page 15: Specifications • The size and weight listed are for the lens only, except as indicated. Canon RF 15-35 2.8 Canon RF 28-70 2 Canon EF 70-200 2.8 Canon RF 85 1.2 Canon EF 500 f/4 L IS II USM + 1.4X III Other: Gitzo Fluid Gimbal Head Gitzo GT4543LS Systematic Series 4 Carbon eXact Long Tripod Benro Mach3 TMA38CL Carbon Fibre Tripod Benro G3 Ball Head Canon Speedlite EL-1 Flash Canon Speedlite 470EX-AI Flashgun Gitzo Adventury 45L Canon EOS-1D X Mark II Canon EF 85mm F1.2L II USM Canon EF 100mm F2.8L Macro IS USM Canon EF 70-200mm F2.8L IS II USM Canon Extender EF 2x III +2 more ZX11 • Veteran Member • Posts: 6,156 nnpXAj. RF 100-300mm f/2.8 L IS USM. A welcome addition to many low-light photographers' kits, the zooming lens maintains a quick f/2.8 aperture throughout the entire 100-300mm range, although first you will have to contend with its hefty price tag. The RF 100-300mm f/2.8 L is listed at $9,499, which at first glance seems high, until you compare it Find helpful customer reviews and review ratings for Canon EF 2.0X III Telephoto Extender for a 2x extender on an f/2.8 lens. extender on a Canon 70-200 f2.8 If you attach a 1.4x Extender to an EF 70-200mm f/2.8L IS III USM lens, for example, it will become in effect a 98-280mm f/4 lens. If you use the same lens with a 2x Extender, it becomes a 140-400mm f/5.6 lens. The 70-200 f4 L needs a bit of help for birding. I know this setup isn't as good as a standalone lens such as the 100-400 or the Sigma 150-500. However, the 1.4 extender is much less expensive and for a bit of birding, I'm wondering if it would be adequate. I would really be interested in hearing from anyone that has used this configuration Canon EF 24-105mm f/4 L IS USM Canon EF 16-35mm f/2.8L II USM Canon MP-E 65mm f/2.8 1-5x Macro Photo Macro Canon EF 180mm f3.5L Macro USM AutoFocus Telephoto Canon EF 70-200mm f/2.8L IS II USM Canon EF 50mm f1.4 USM Canon EF 85mm f/1.8 USM Canon EF 100-400mm f/4.5-5.6L IS USM Telephoto Zoom Canon Extender 1.4 III Sigma 105mm 1:2.8 DG Macro The 70-200 is not the ii version. Then I'd avoid TCs, the focusing isn't going to be great with a TC. The 100-400 is pretty good, but the 70-300L is all around better (~$1100 used) aside from not going to 400. It doesn't take a TC though. I have the 70-200 2.8 L Non IS and have used both the 2x and 1.4x extenders.

canon extender ef 2x iii 70 200 f2 8