AE Lock - do you use it?

[Craddie]

I only use it in tricky high-contrast situations when I have to spot meter one spot and focus in another.....

 

[JerryPH]

Nikon D700 function F7 (D3 function F6), AE lock... used in another manner, if I am in A-mode (aperture priority), I can meter off EXACTLY what I want, hit the AE/AF lock button, lock in the exposure and then take several shots varying aperture (playing with the DOF), each time and the shutter speed compensates exactly... meaning, it doesn't re-meter in between shutter button presses.

If I click one notch on the aperture, it automatically clicks one notch on the shutter speed the other way to maintain that exact same exposure, so I can vary aperture several times, take several pictures and/or recompose and never lose that exact setting that I want.

Just a variation on a theme.
I am sure other cameras can do this, but I don't think all can.