Adapting nikon "G" lenses isn't very simple for canon. But, if you are actually going to upgrade, it could be worth trying. The nice thing about tokinas is that they hold their value very well, you could buy a canon mount 11-16 now and sell it in 6 months for the same price, no problem.
Check out this adapter though, could be worth it.
Something like this will adjust the aperture of the "G" lens manually, you won't know what exact f stop you're at, but it will work.
Evan Heath Visual
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