Compression absolutely kills the images here,though an inkling is conveyed.
The 7D/100-400 is a VERY impressive machine,as it's(7D's) bolstered AF performance,does exceptionally nice things with said glass. While I prefer my 1DMK3 to the 7D,the 1.6x crop is a very nice crutch.
The 7D absolutely crushes the FF 5D2 in AF,for anything moving even a smidge.
Go Heliopan filters.
Hint.....................
