Canon F-1 New Stop down slide button

Hello all,

 

Understanding the general metering function of the stop down lever/button, my question is this:

 

When mounting my [new/n] FD lenses onto the camera body, does this button/slide need to be pressed in or left alone in the retracted (extended) position. Same with active shooting, left in or out, no naughty pun intended... :)

 

I don't use this stop down metering function, just shoot and meter regularly.

 

Thanks much.

Leave the button alone in normal use unless you have a specific reason to activate it.

 

If you're not previewing DOF or metering in stop-down mode, you have no reason to use it.

 

In fact, having it out while mounting a lens will likely be detrimental as the stop down lever on the lens won't engage the one on the body properly. When you press the stop-down button in the lens, in the best case you may end up with the two jammed against each other(best case) or in the worst case may damage something.

Thanks, Ben. That's what I was looking for.

Canon is very specific about not mounting the lens in the stop down position. That goes for the older F1, too.

 

As one who uses that features frequently, I'll admit that I have mounted a lens with the button out, Luckily for me, other than screwed up exposures, no damage has ever been done. (I guess after many years of use I'm entitled to a mistake or two)

Edited June 1, 2019 by chuck909

I've don e same thing with T90. Resulted in dreaded "EEEE" message, my heart stopped for the moment ....

The whole stop-down lever or button business on the FD Canons is a holdover from the earlier cameras that took the FL lenses, in which metering was done with the stop-down button engaged. The biggest difference between the FL and FD lenses is the FD lenses allow for full-aperture metering. But this button was retained in FD-compatible Canons so that the earlier FL lenses could still be used. The stop-down lever or button on FD Canons must be engaged in order to properly meter a scene with FL lenses. When it is engaged, a reference mark is revealed, which is used to determine correct exposure. The stop-down lever or button can also be used to preview depth of field with FD lenses, of course, but one does not meter a scene with the FD lenses the way one has to do with FL lenses.

and be sure to only use it when the lens is NOT in the A position!!!!

and be sure to only use it when the lens is NOT in the A position!!!!

 

That actually won't hurt anything.

 

The "A" position is more or less Canon's way of locking the aperture ring to the minimum position. Of course, it also kicks out a tiny pin in the base to signal to certain cameras that the lens is set there(the F-1, both versions, has a blank hole in the mount to allow it to be there since there's a way to get shutter priority mode on both cameras). If you press the DOF preview with the lens on A, it will just stop down all the way.