Have tried the 100-400 & am still undecided as to whether I purchase or not. As luggage weight is not a problem I may well take Canon 5DIII & Sigma 150-600 & hire a Fuji 100-400 for 2 weeks.. Cost will be about $220 & I will have all bases covered + back ups. Weight is still far far less than taking a 5D111, 1DIII,500 f4 & 100-400,16-35 & 24-70.