Don’t sell them all as you can mount an EF lens on FX mount.
You can buy adapters for the Fujifilm X camera that allow you to mount an Canon lens on Fujifilm camera, these are XF to EF adapters that you can buy online and possibly in a camera store.
One thing to note is that this adapter will be Manual Focus only.
Use Canon EF Lens at Native Aperture
The aperture on the EF Lens is controlled electronically by the EOS Camera its attached to. Otherwise when not connected to a Camera body the lens sits wide open at its native aperture, so if you have F1.8 lens it mean it remains at F1.8. If you have a F4 lens, it remains at F4.
So to use these lens at their native aperture, you can simply attach the lens by following the steps below. Skip Step 1 and follow from Step 2 to 5 in the section “Use Canon EF Lens at Specific Aperture“.
Depth of Field (DOF) button
This button is located near the bottom of the lens mount either on the left or right of the camera body. Depending upon your model of the camera you may want to refer to the Instruction Manual of your specific model. It let’s you preview the depth of field that will be achieved when you press the shutter.
For example, if you are shooting with a lens that is F1.8 natively but in Aperture Priority or Manual mode you’ve set the Aperture to F2.8 then pressing the DOF button will change the lens aperture to F2.8. Here is where this button is by default on Canon 80D and 7D.
Use Canon EF Lens at Specific Aperture
Lock the aperture of your lens with Depth-of-filed button on the Canon camera.
To change the aperture later on, you will need to re-attach the lens back onto the Canon camera body.
Detach the lens while the camera is on and DOF button is pressed. Now your lens is locked to aperture you selected.
Make sure that you switch the lens and camera to MF (manual focus).
Tip: Turn on Focus Peaking if your Fujifilm X Camera has this feature. It makes manual focusing super easy!!