Argus C44/C44R Manual: Installing Lenses
TO INSTALL ANY LENS, first align the red dots on the body lens mount and align the red dots on the rear of the lens.
Place
the lens on the mount so the notch on the rear of the lens fits over
the square projection on the camera mount. When seated, rotate the lens
clockwise to lock. Check to see the lens is locked -- it should not
turn. Never leave the camera without a lens installed. Avoid changing
lenses in direct sunlight.