Option
Description
Mac OS shortcut key
Windows shortcut key
8:1
Display at zoom level 8:1 (an 8 x 8 grid of pixels on the computer screen is used to represent 1 pixel in the image).
Ctrl+Shift+8
4:1
Display at zoom level 4:1.
Option 
4
Ctrl+Shift+4
2:1
Display at zoom level 2:1.
Option 2
Ctrl+Shift+2
1:1
Display at zoom level 1:1 (1 pixel on the computer screen is used to represent 1 pixel in the image).
1
Ctrl+1
1:2
Display at zoom level 1:2 (1 pixel on the computer screen is used to represent 2 x 2 grid of pixels in the image).
2
Ctrl+2
1:4
Display at zoom level 1:4.
4
1:8
Display at zoom level 1:8.
8
Ctrl+8
1:16
Display at zoom level 1:16.
6
Ctrl+6
1:32
Display at zoom level 1:32.
3
Ctrl+3
1:64
Display at zoom level 1:64.
1:128
Display at zoom level 1:128.
1:256
Display at zoom level 1:256.
1:512
Display at zoom level 1:512.
5
Ctrl+5
Zoom In
Increase the magnification of the image by one zoom level.
+
Ctrl +
Zoom Out
Decrease the magnification of the image by one zoom level.
–
Ctrl –
Fit to Window
Display the entire image in the main window.
0
Ctrl+0