If the selector of aperture
remains unchanged with its two positions as on the model III, a rotative
ring located around the lens allows to select one of the three available
speeds (B, 1/25, 1/100 sec).
Some minor changes are
noticed onto the body of the camera which is now labeled "4", like the
Photax III Blindé.
Slits have been added
on the perimeter of helical tube to improve the prehension when moving
it in position.