Mamiya 645af - stop down metering

[hankchinaski]

I was reading the wikipedia article about m645 and it says "older manual lenses require stop down metering on af bodies".

Can somebody confirm: the stop down metering process, in the case of an af body and an older lens, consists in pushing the dof preview button, and at the same time, adjust aperture/time until exposure indication is right? What I mean is that it's just a matter of metering with the dof preview button. Or maybe the aperture/time can only be changed when the dof button is up, so I have to release the dof button, set the aperture/time again, push the button, read the metering, etc, until the aperture/time is right?

 

[cramej]

IIRC, the aperture on AF lenses is electronic so no need to use the DOF preview button.

 

[hankchinaski]

IIRC, the aperture on AF lenses is electronic so no need to use the DOF preview button.

Thanks, what about about older manual lenses?

 

[MattKing]

With the manual focus lenses, in order to meter, you have to switch the switch on the lens from A (open aperture) to M (shooting aperture). You then set the aperture on the lens to your shooting aperture. Adjusting the aperture will change the meter reading - you either do that or adjust the shutter speed to set the exposure. Stopping down the aperture will also darken the viewfinder. This is the way that all cameras with built in meters operated before the "modern" improvement of open aperture metering was introduced.
There is no stop down lever on the manual focus cameras, so my guess is that a stop down lever on the AF won't engage anything on the manual focus lens, but I could be wrong about that.
Most likely you will end up metering separately - focusing and composing with the aperture set wide open, and then metering (and checking depth of field) with the aperture adjustments, and associated darkening of the viewfinder.

 

[cramej]

Thanks, what about about older manual lenses?

Matt said what I would have said had I not been on my phone.