AgX: one is not attaching the lens to the mount in this case so one can 'make' the flange distance any distance one wants. Again, the 'in focus' is fleeting due to the hand holding the lens. - David Lyga
David:
If the flange distance is much less for the lens then the camera is designed for, you would need to put the lens inside the camera to get it close enough for your test to work with distant objects.
Close-up objects are different.