OK, silly to ponder something so easily tested: Indeed on an F-1N you can have the DOF preview lever actuated, mount a lens, then put it back to its normal position, and it won't jam the camera. (The aperture obviously stays wide open when you take pictures, regardless of where the ring is, but it doesn't jam the camera.)
Anyone with an older F-1/F-1n want to try this, just so I know I'm not going insane when I remember that as being a case where the camera would no longer wind until you removed the lens and got things put right again? I definitely remember thinking that red dot needed to be larger to warn you more! The classic scenario is unmounting a lens when you have the DOF preview lever engaged... you can't then mount another lens until you've unengaged it first.
I have my original F-1 right besides me. With the DOF preview engaged, I have no problem mounting or un-mounting an FD lens. I can also advance the film, press the shutter button, and fire the shutter. The camera works 100% as normal with the exception that the lens will be always wide-open, since the aperture engagement lever is set in the stop-down location.
Originally Posted by frobozz
The question remains what happens if the apertur actuator on the body is caught (as you described) and the DOF-previw button is dis-engaged.
I assume the body works normal. So there would be no sign of warning about mal-coupling of the lens. Except for that little red dot in the mirror box.
Thus one might have engaged the DOF-button, changed lenses "blind" witgh button still engaged, then realizing anbout the error, die-engaging the button and thinking everything is. That is not (no harm, but malfunction).
As general rule anyone grabbing for a Canon out of the FD-range with DOF-button with the lens fitted and not knowing about the recent history of handling (eg. others had access to the camera) should either:
-) take off the lens and before setting it on again check for the aperture actuator on the body to be in neutral position,
-) keep the lens on, set the aperture dial on the lens to a small aperture, engage the DOF-button and check in the viewfinder on the effect, then set both in neutral- resp. A-stand again.
(I hope not to have deviated too much from the OP's question as this of interest to anybody new to the FD-system.)
I'm not quite sure I follow you, but:
----if the DOF-preview of an old F-1 is engaged before you attach a FD lens to the body
----if you then attach the lens
----if you then disengage the DOF-preview and remove the lens from the body
----you will hear a metallic "twang" as the aperture lever returns to it's rest position. This won't damage the camera or damage the lens.
I'm not quite sure why all this discussion about something that rarely happens. In the 40+ years I've been using FD gear, I've never had any problem with using the DOF-preview and attaching or removing a lens. This is a total non-issue, at least for me.
I was drawing a scenario where the button erroneously was kept engaged during changing the lens.
When I got to use my first camera out of the FD-range, the AE-1 when it was released, I somehow was puzzled by that warning in the manual about that actuator as long as I realized its working mechanism. So I thought a newbie might be puzzled too.
On the New F1 in Manual and Stop Down Manual modes the lens can not be set on A and the shutter dial cannot be set on A . Any type of finder can be used and the use of a motor drive is optional. For Aperture Priority AE and Stopped-Down AE modes the lens can not be set on A. The shutter speed dial is to be set on A. The AE Finder FN must be used and the motor drive is optional. For Shutter-Priority AE and Electronic Flash AE modes the lens is set on A and the shutter dial can be set to any speed. For Electronic Flash AE mode the shutter cannot be set on B. Any type of finder can be used and the use of a motor drive is required.
Setting the Aperture ring and Shutter Speed dial both to A (with any type of finder installed) at the same time will cause the aperture to close to its smallest value and the camera will then set the shutter speed automatically to give the correct exposure if possible. This can result in long or wrong exposures.