Canon EOS 5DS R Instruction Manual - Page 406

3 Custom Function SettingsN Same exposure for new aperture If the mode (manual exposure shooting) is set and the ISO speed is set manually (other than Auto ISO or H (12800) is set), the maximum aperture's f/number may change to a higher number (smaller aperture) if you do any of the following: 1. Change the lens, 2. Attach or detach an Extender, or 3. Use a zoom lens whose maximum aperture f/number changes. If you then shoot at the exposure setting as is, 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 before you did 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 do 1, 2, or 3 and the maximum aperture f/number increases, adjust the ISO speed and shutter speed before you shoot. ISO: ISO speed If you do 1, 2, or 3, the ISO speed will automatically increase to compensate for the amount that the maximum aperture f/number increases by. The same exposure that would be obtained before you did 1, 2, or 3 is thereby obtained. Tv: Shutter speed If you do 1, 2, or 3, a slower shutter speed will automatically be set to compensate for the amount that the maximum aperture f/number increases by. The same exposure that would be obtained before you did 1, 2, or 3 is thereby obtained. 406