Iso Auto - Canon EOS-1DX Instruction Manual

As H1 (equivalent to ISO 102400) and H2 (equivalent to ISO 204800) are
expanded ISO speed settings, noise (such as dots of light and banding) and
irregular colors will be more noticeable, and the resolution will be lower than usual.
If you use a high ISO speed and flash to shoot a close subject, overexposure may result.
If [ISO speed range] is set to [Maximum: 51200] and you shoot a movie
while ISO 32000/40000/51200 is set, the ISO speed will switch to ISO 25600
(during manual-exposure movie shooting). Even if you switch to still photo
shooting, the ISO speed will not switch back to the previous ISO speed.
If L (equivalent to ISO 50) is set and you shoot a movie, the ISO speed
will switch to ISO 100 (during manual-exposure movie shooting). Even if
you switch to still photo shooting, the ISO speed will not switch back to L.
If ISO 32000 or higher (when the camera's internal temperature is low,
ISO 20000 or higher) is set, the maximum continuous shooting speed
with <o> will be approx. 10 shots/sec.
Under [z2: ISO speed settings], you can use [ISO speed range] to
expand the settable ISO speed range from equivalent to ISO 50 (L) to
equivalent to ISO 204800 (H2) (p.132).

ISO Auto

If the ISO speed is set to "A" (Auto), the actual ISO speed to be set will be
displayed when you press the shutter button halfway. As indicated below,
the ISO speed will be set automatically to suit the shooting mode.
Shooting Mode
d/s/f/a
Bulb
With flash
*1: The actual ISO speed range depends on the [Minimum] and [Maximum]
settings set in [Auto ISO range].
*2: If fill flash results in overexposure, ISO 100 or a higher ISO will be set.
*3: When using bounce flash with an external Speedlite in the <d> mode, the ISO
speed will be set automatically within ISO 400 - 1600.
If [Auto ISO range]'s [Maximum] is set to [51200] (p.133) and ISO 32000 or higher
(when the camera's internal temperature is low, ISO 20000 or higher) is set automatically,
the maximum continuous shooting speed with <o> will be approx. 10 shots/sec.
ISO Speed Setting
Automatically set within ISO 100 - 51200*
Fixed at ISO 400*
1
Fixed at ISO 400*
1
i: Setting the ISO Speed
* *
2 3
1
131