The ARRI Signature Zoom 1.7x Extender is a high-performance optical device which is optimized for the Signature Zoom 65-300/T2.8 and Signature Prime 280/T2.8. It delivers its best optical performance with just those two lenses. We can only guarantee mechanical clearance for these two lenses, so please don’t use the extender with any other lenses. When you use the extender with these two lenses you have to remove the Magnetic Rear Filter Holder from the base lens and put it onto the rear of...