> > This is what I wonder: > > I understand that camera picks the rigth EV based on whatever the > algorithm > it has (center weighed, spot, evaluative whatever). But after > that, how does > it decide which combination of aperture and shutter speed? > > -e
Hi Evrim, >From what I can tell the "(P)rogram" picks a shutter speed based on the focal length lens mounted and the aperture falls into place unless the EV is too low then it picks a faster aperture and as the light get lower a slower shutter speed. Where it starts from I don't know as the shutter speeds and apertures selected seem to be all over the place. I verified this by mounting a medium tele (EF 135mm 2L), and metering a plain white wall lit by full daylight then mounted a short lens (EF 17-35 2.8L), and metering the same AREA as the long lens. I then repeated the test with the blinds closed down some and the shutter speeds tended to stay the same but the apertures got larger. But in all cases the shutter speeds were faster for the longer lens and slower for the shorter lens. Regards, Chip Louie * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
