I recently found that in manual mode if I set aperture and shutter speed but leave ISO on auto the metering will adjust the ISO to get the "right" exposure.
How many of you guys use manual mode this way?
What are your thoughts?
I use this all of the time and find it works great. As you mentioned you can set your DOF and SS, and still get a normal exposure every time, especially in varying lighting conditions.
The only time that it doesn't work well is if you want to use +/- EC to raise or lower your exposure settings. Sometimes you just need to override the cameras exposure settings, since the meter can be fooled.
For those conditions, I'll use AV or TV, depending on what is more important and then I'll use +/- EV with a fixed ISO, with ISO safety shift enabled (which I always leave on).
Without getting too technical, if light is limited, I'll use a custom shooting mode in AV with a wide open aperture, and then I'll set my minumum SS to 1/1000 sec (custom setting in 1DX) for sports with Auto ISO. E/C can also be applied to this, since I'm not shooting in manual mode. In sports it's important to control your background, SS, and exposure compensation, and the above setting alllows me to do all of those things.
For controlling SS of other cameras, I use TV and auto ISO or fixed ISO with safety shift (depending on which settings controls my aperture/background better) to avoid blurry shots, or I would use Manual mode with Auto ISO.