Complete side-issue and not directed at you, but Nikon shooters give that old creaky Canon 100-400 too much credit for a lens that is unremarkable in performance, specifications, and modern design capabilities. It has old first generation AF-S, 2-stop at best VR, and is a dust sucker push-pull zoom with maybe OK optical sharpness. So it's chief benefit is it's cheaper price, that seems to be about it on its list of good attributes but in most ways it is as ancient and in need of replacement as the older Nikon 80-400. This will happen soon enough I expect and Canon will at that time inevitably rebalance its pricing.
And don't get me started on the attributes of the Canon 18mp crop sensor, which is all that's available in their crop cameras. Again, old design, banding, low dynamic range, poor high ISO. Easily outclassed by the sensors in any number of Nikon cameras available for the last few years and my take is even the old D300 holds it own against this Canon sensor head to head.