I have the Sigma 150-600mm f5-6.3 c with the 1.4 teleconverter by sigma, and an Eos 80D. I'm very surprised how sharp your image is. I always found my images to be sharper when photographing without tc. I even send all this gear to sigma for adjustment, but still don't get such amazing results. Guess i need to try harder in future :DHere's where I'm coning from. I have a Canon T7 with the 75-300 lens. Some of you will recall I had inquired about the Sigma 150-600 lens. I was browsing through Lenses and found a conversation that mentioned keeping a lens that goes to 300mm and getting a converter. Canon's converter is cheaper than buying a new Sigma 150-600 lens.
Just imagine, a Canon EF 100-400mm f/4-5.6L II IS USM lens combined with a EF 1.4x III extender gives you a focal length of 560mm. Although the focal length is only 40mm shorter compared to the RF
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