Pay attention that teleconverter should be used with lenses that are thought for teleconverter, check the compatibility list or you cannot mount together.
Canon is only for ef mount, ef-s not work be cause le see protrude inner the mount.
And not all ef can be connected.
I had canon x2 that work fine for sharpness (I use only with series L lenses) but remember that also multiply the iris, that mean I use it with 70-200 2.8 is II, now I had 140-400 5.6 lenses.
I had 18-35 sigma Ef-a and you cannot mount on multiplier.
You can see here sigma and canon mount, not possible with Ef-s lenses.
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