just meter the scene in auto, change apertures off auto to the desired aperture or change shutter to get the desired aperture by the auto system. Not really an issue.
But, to me, anyway, this really is an issue. Last night I wanted to do some night shots of a recently-opened high-profile pedestrian bridge, so I grabbed the one GIII which was recalibrated to use 1600 film. When I got there, I realized that I had a subject that was far more contrasty and bright in small places than I imagined, so I realized that if I shot totally in auto, I would get overexposed and blown-out highlights. Here's an example.
So I did as you said, metered as usual, then took the camera down, switched to manual, adjusted the exposure to what I thought was best, recomposed (everybody had moved by then), and then shot. Rinse, repeat!
I *REALLY* wish all I had to do was to tweak one dial and watch the needle. I should have probably taken the Pentax or the Mamiya (totally manual, only goes to 800, but I can fudge), but the 40mm was the better lens for this job.
It worked, but it was a major pain and took far longer for each exposure where I felt the need to do something other than what the meter was suggesting.
Oh well ...
And then one other shortcoming with the GIII, but this is really widespread of other lenses of that speed and vintage.
Here's another from that shoot, but this is not one of the keepers.
No, this is not a fountain, it's a sculpture garden with these vertical things illuminated by changing colored lights. When metering it, it was right on the threshold of releasing the exposure lock, lens wide open, at 1/30. I went ahead and shot as suggested. I should have probably switched to 1/15 and stopped down, because if you look at the lights toward the upper left and right, they are football shaped, showing the astigmatism of this lens when used wide open.
The Mamiya SD (f1.7, 48mm) does the same thing to an extent, but not as much. They tell me (the ubiquitous "they") that most lenses of this type and speed of that vintage will show this to one degree or another.
It's a shorcoming of the GIII that annoys me sometimes.
Yeah I know, I want perfection.
Overall, the GIII is a great camera, but it's not perfect by any means.