Canon EOS 5D Mark III Instruction Manual (en)

u Magnified View
Under the [33] tab, when you select 
[Magnificatn (apx)], you can set the 
starting magnification and initial position 
for the magnified view.
1x (no magnification)
The image will not be magnified. The magnified view will start with 
the single-image display.
2x, 4x, 8x, 10x (magnify from center)
The magnified view will start at the image center at the selected 
Actual size (from selected point)
The recorded image’s pixels will be displayed at approx. 100%. The 
magnified view will start at the AF point that achieved focus. If the 
photo was taken with manual focus, the magnified view will start at 
the image center.
Same as last magnification (from center)
The magnification will be the same as the last time you exited the 
magnified view with the <x> or <
u> button. The magnified view 
starts from the image center.
 Magnification Settings
With images taken with [Live mode] or [u Live mode] (p.209), the 
magnified view starts from the image center.