So my new lens came for my newly aquired Ansco 8x10. It's a Linhof Schneider Symmar 210/370mm convertible lens. It looks to be in good shape and the shutter functions nicely, however there doesn't appear to be any diaphram. Is this normal for this type of lens? All it seems to be is two elements one on each side of the shutter. Can someone explain this one to me?

Much appreciated,

Jim