Multipliers are only compatible with selected EF lenses, including the EF 70-200mm f / 2.8L USM, EF 70-200mm f / 2.8L IS USM, EF 70-200mm f / 4L EF 100-400mm f / 4.5-5.6L USM, EF 400mm f / 4 DO IS USM L-series and objectives fixed length of 135 mm or more. In addition, must take into account the multiplication by two of the opening, so actually, you have to take if one already has 70 200 f / 2.8 IS USM because the stabilization offset the shutter which suddenly on equal terms, will increase the exposure time. In addition to 5.6 no autofocus problems, and small sensors, torque multiplier goals + gives 220-640 mm f / 5.6L IS USM which is great !!! Apart from this use, the openings 8 or 11,2 often force a rise in ISO and sometimes a manual focus, thinking about it 2 times before buying if one has not the famous zoom for which looks like it was designed ...
