Can confirm it works perfectly and autofocuses at f/8 on the EF IS non-L 70-300mm. I don't think its a great teleconverter, if you have the compatible L lenses, you can use the Canon ones - which are higher quality glass. PhotosByHall's gear list: Canon EOS 7D Mark II Canon EOS 5D Mark IV Canon EOS M50 Canon EF 50mm F1.8 II Canon EF 17-40mm f/4
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