Canon MARK IV User Manual (en)

Set the ISO speed (image sensor’s sensitivity to light) to suit the 
ambient light level.
Press the <Z> button.
Set the ISO speed.
While looking at the top LCD panel or 
in the viewfinder, turn the <6> dial.
ISO speed can be set within ISO 100-
12800 in 1/3-stop increments.
With “A” selected, the ISO speed will 
be set automatically (p.65).
ISO Speed Guide (No flash)
: Setting the ISO Speed
ISO Speed
Shooting Situation
Flash Range
100 - 400
Sunny outdoors
The higher the ISO speed, 
the farther the flash range 
will be.
400 - 1600
Overcast skies or evening time
1600 - 12800, 
H1, H2, H3
Dark indoors or night
If [8C.Fn II -3: Highlight tone priority] is set to [1: Enable], “L” 
(equivalent to ISO 50), ISO 100/125/160, “H1” (equivalent to ISO 12800), 
H2” (equivalent to ISO 25600) and “H3” (equivalent to ISO 102400) 
cannot be set (p.215).
Using a high ISO speed or shooting in high-temperature conditions may 
result in more grainy images. Long exposures can also cause irregular 
colors in the image.
When you shoot at high ISO speeds, noise (horizontal banding, dots of 
light, etc.) or irregular colors may appear. Also, if you shoot with the ISO 
speed range upper limit expanded to H1, H2 or H3 with [8C.Fn I -3: Set 
ISO speed range
] (p.208), noise and irregular colors may become more 
With [8C.Fn I -3: Set ISO speed range], the ISO speed range can be 
expanded from ISO 50 (L) to ISO 102400 (H3).