Mamiya 645 Pro lens question

Does the orientation of the prong matter when changing lenses on my 645 Pro? It does matter on my Nikon Nikkormat when I change lenses, if I want the meter to work. If so, what is the correct sequence to follow when I attach a new lens to my Mamiya?

Thanks to all who reply.

With best regards,

Stephen

AFAIK, it is auto indexing. At least it seemed to be on my M645's when I had the metering prism. The Nikkormat is an older camera from before Nikon introduced AI, while your camera is more modern in comparison.

You should be able to find an instruction manual in PDF form somewhere online to find out for sure.

Yes, it does matter... If you look at your camera body closely, you'll notice there is a pin sticking out from the panel that says "Mamiya 645". That pin couples with the prong and relays aperture information from lens to the body. The pin must reside between the opening of that prong.

It IS possible to attach it incorrectly. (I have done it)

There is no sequence per say. You can attach them together in only one way and in one direction. You just have to make sure, when it's all done, pin is correctly seated. It's hard to explain in words, but the pin does move and detract to facilitate this coupling. If not, take the lens off and do it again.

Does that help at all??