As to the 2X, I have some of the sharpest glass Canon has made (200 f2, 300 and 400 f2.8) and in my experience the 2X results in an excessive loss of sharpness, contrast, and overall image quality. It is a great device for turning an excellent quality lens into image results like that from a much lesser quality lens.
BH CA2XRF • MFR # 4114C002. 54 reviews. RF-Mount Teleconverter. 2x Magnification Factor. Maintains Metering, Autofocus, and IS. Dust and Water Resistant. Extend the reach of select 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
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