Bought this to use with Sony Fs5. It works but does not seem to stay connected. The aperture can be controlled by the camera but it flashes with every click. It then loses contact and the aperture read out is blank. Unmount the unit from the camera slightly and tighten again and it regains contact. Have not really tested lots of different lenses at length but use it with Tamron 24-70 2.8 and Canon 70-200 2.8. It gets me by but there is no substitute for the Speedbooster(at 4-5x the price!).
Easy to use
Would you recommend this product to a friend? Yes