Canon EOS-1Dx Mark II User Manual - Page 427

3 Custom Function Settings Same exposure for new aperture C.Fn2 If the mode (manual exposure shooting) is set and the ISO speed is set manually (except when set to ISO Auto), the open aperture value may change to a higher number (a smaller aperture) if you perform any of the following: 1. Change the lens, 2. Attach an Extender, or 3. Use a zoom lens whose open aperture value (f/number) changes. If you then shoot while the maximum aperture is set, the image will be underexposed by the amount the maximum aperture f/number changes to a higher number. However, by changing the ISO speed or shutter speed (Tv) automatically, you can obtain the same exposure that would be obtained without performing 1, 2, or 3. OFF: Disable Automatic changes in settings to maintain the specified exposure will not be applied. The ISO speed, shutter speed, and aperture already set will be used for shooting. If you perform 1, 2, or 3 and the maximum aperture becomes slower, adjust the ISO speed and shutter speed before you shoot. ISO: ISO speed If you perform 1, 2, or 3, a higher ISO speed will be set automatically to compensate for the number of stops the maximum aperture has become slower. The same exposure that would be obtained without performing 1, 2, or 3 is thereby obtained. The ISO speed will change automatically within the range set with [Range for stills]. ISO/Tv: ISO speed/Shutter speed If you perform 1, 2, or 3, a higher ISO speed will be set automatically to compensate for the number of stops the maximum aperture has become slower. If the ISO speed reaches the upper limit of the range set with [Range for stills], a slower shutter speed will be set automatically. The same exposure that would be obtained without performing 1, 2, or 3 is thereby obtained. The shutter speed will change automatically within the range set with [83: Set shutter speed range]. 427