ISO: Changing the ISO Speed to Suit the Light Level (EOS Rebel T7)

Article ID: ART173770 | Date published: 02/28/2019 | Date last updated: 02/28/2019


ISO: Changing the ISO Speed to Suit the Light Level  (EOS Rebel T7)


Set the ISO speed (image sensor’s sensitivity to light) to suit the ambient light level. In Basic Zone modes, the ISO speed is set automatically
Press the button.
  • [ISO speed] will appear.
Set the ISO speed.
  • Press the keys or turn the  dial to select the desired ISO speed, then press .
  • With [AUTO] selected, the ISO speed will be set automatically

  • Under [3: Custom Functions (C.Fn)], if [2: ISO expansion] is set to [1: On], “H” (equivalent to ISO 12800) can also be selected.
  • Under [3: Custom Functions (C.Fn)], if [10: Flash button function] is set to [1: ISO speed], you can set the ISO speed with the <D> button.
  • Under [3: Custom Functions (C.Fn)], if [6: Highlight tone priority] is set to [1: Enable], ISO 100 and “H” (equivalent to ISO 12800) cannot be selected.
  • Shooting in high temperatures may result in images that look grainier. Long exposures can also cause irregular colors in the image.
  •  When you shoot at high ISO speeds, noise (such as dots of light and banding) may become noticeable. 
  • If you use a high ISO speed and flash to shoot a close subject, overexposure may result. 
  • As “H” (equivalent to ISO 12800) is an expanded ISO speed setting, noise (such as dots of light and banding) and irregular colors will be more noticeable, and the resolution will be lower than usual.

If the ISO speed is set to [AUTO], the actual ISO speed setting will be displayed when you press the shutter button halfway. As indicated on the next page, the ISO speed will be set automatically to suit the shooting mode.

*1: Depends on the maximum ISO speed limit set.
*2: If fill-in flash will cause overexposure, ISO speed may be reduced, down to a possible minimum of ISO 100.
*3: If bounce flash is used with an external Speedlite in a Basic Zone (except <>) mode or <P>, ISO 800 - ISO 1600 (or up to the maximum limit) will be set automatically.
*4: Fixed at ISO 400 in <> mode. If bounce flash is used with an external Speedlite in <> mode, ISO 400 - ISO 1600 will be set automatically.
*5: Fixed at ISO 400 if the maximum limit is ISO 400.
  • When [AUTO] is set, the ISO speed is indicated in whole-stop increments. However, the ISO speed is actually set in finer increments. Therefore, in the image’s shooting information, you may find an ISO speed such as ISO 125 or ISO 640 displayed as the ISO speed. 
  • In the <2> mode, an ISO speed other than ISO 100 may be displayed, but the actual ISO speed used is the one shown in the table above.

Setting the Maximum ISO Speed for [AUTO]
For ISO Auto, you can set the maximum ISO speed limit within ISO 400 - ISO 6400.
Under the tab, select [ISO Auto], then press . Select the ISO speed, then press

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