FAQ Adapters: How to use a Canon EOS EF/EF-S Lens on an adapter and still be able to adjust the lens aperture to shoot and expose properly.Updated a year ago

Typically, there are no ways to control the aperture of Canon lenses, but we have found a few workarounds. But unfortunately, these will only work if you do have a Canon EOS-mount camera available:

1)    Put the Canon EOS lens on a Canon EOS body and turn the camera on
2)    Put the camera into Manual Mode and set the aperture to what you want to shoot at (ie, f/8)
3)    Set the shutter speed to something super long, 30 seconds for instance
4)    Take a picture, and during the 30-second countdown, remove the lens from the camera
*     This will not harm the lens or the camera, the moment you put the lens back on a Canon EOS camera, the aperture will return to normal

OR

1)    Put the Canon EOS lens on a Canon EOS body and turn the camera on
2)    Put the camera into Manual Mode and set the aperture to what you want to shoot at (ie, f/8)
3)    Press your depth of field preview button
4)    While still holding the depth of field preview button, remove the lens.

Either method should lock the lens temporarily to what you set it at, f/8 for instance. So when you put the lens on the adapter you will be preset to f/8. One problem though is that this will make the viewfinder dark and hard to see or focus, so it's best to do it right before you are ready to shoot. The other problem is that anytime you want to shoot at anything other than f/8, you will need to go through those steps again, so it’s not a fast or elegant solution, but it will work.

Hope this helps, if there is anything else we can do please let us know, thanks, and happy shooting!