https://community.usa.canon.com/t5/Speedlite-Flashes/Canon-Speedlite/m-p/17481#M1466 <P>All compatible.&nbsp; When you say small, you refer to size and not price?&nbsp; I think that unless size were actually your concern, I would spend up a bit beyond the 270 for use on a 5D3.&nbsp; Not just for the features, but also for the flash power/range.</P> Fri, 15 Mar 2013 18:48:52 GMT ScottyP 2013-03-15T18:48:52Z https://community.usa.canon.com/t5/Speedlite-Flashes/Canon-Speedlite/m-p/17471#M1465 Looking for a small flashgun. Are units like the canon 270ex and upwards all fully compatible with 5D mk lll? Fri, 15 Mar 2013 14:26:27 GMT https://community.usa.canon.com/t5/Speedlite-Flashes/Canon-Speedlite/m-p/17471#M1465 Ballyharry 2013-03-15T14:26:27Z https://community.usa.canon.com/t5/Speedlite-Flashes/Canon-Speedlite/m-p/17481#M1466 <P>All compatible.&nbsp; When you say small, you refer to size and not price?&nbsp; I think that unless size were actually your concern, I would spend up a bit beyond the 270 for use on a 5D3.&nbsp; Not just for the features, but also for the flash power/range.</P> Fri, 15 Mar 2013 18:48:52 GMT https://community.usa.canon.com/t5/Speedlite-Flashes/Canon-Speedlite/m-p/17481#M1466 ScottyP 2013-03-15T18:48:52Z