So I bought a Nikon F mount to Canon EOS adapter so I can use Nikon lenses on my Canon body.
Unfortunately my Nikon lenses are stuck at their smallest aperture while on the Canon body and the camera is unable to control the apertures.
Is there an easy fix for this? Do I need some kind of extension that will add the ability to set the aperture?
I suspect the lenses you have are the 'G' type AF lenses, that have the electronic diaphragm. Such lenses will not have automatic aperture control on the bodies if they are not 'F' mount and since they don't have an external aperture control mechanism, I don't think that manual aperture control is possible in this case.
You will have to check if your adapter does provide any such function at all.
However this doesn't apply to lenses that are AF-S 'G', if you have the 'E' types or the AF-D/AF, I got no idea.
EDIT: as @Michaelclark explains in comment, 'G' type lenses have mechanical diaphragm. But it can only be controlled by camera.
You probably need a completely different adapter that allows for aperture control, if you are attempting to adapt newer Nikon G lenses that have no aperture ring.
These are relatively rare, and usually more expensive. For example, Fododiox's ring for F-mount lenses without aperture control are roughly US$20, but the one with aperture control is about $70, and with an AF confirmation chip added, is about US$90.
