EOS R Image doesn't get darker or brighter in Av mode

[Twisted118]

So for some reason today in AV mode when I adjust the ISO or Fstop I don't see it adjust as I adjust it. Before today I can higher and lower the ISO and see the picture go darker or lighter... I'm really confused as to why suddenly it doesnt do it anymore ? 

For people that say you cant see the manual adjustment your wrong I definitely could see it as I adjusted 

Many thanks for the help 

Any help appreciated 

[deebatman316]

If Auto ISO is set you can't see it. Or if your using flash it won't work either.

[Twisted118]

Hi I'm sliding the iso bar back and forth and still not seeing adjustments ? 

[deebatman316]

Is exposure simulation turned on?

[Twisted118]

Yes it is and when it wasn't it wouldn't show in manual mode. And now it's on it shows in manual mode but still doesn't want to show in AV mode 

[p4pictures]

With exposure simulation on

• Manual mode - changes to shutter speed, aperture, ISO are reflected in the display as long as ISO Auto is not used
• M mode with auto ISO - exposure compensation will be displayed, changing the brightness of the screen.
• Av, P, Tv modes - changes to ISO are compensated by the camera changing one of the other parameters - eg shutter speed while in Av mode - and the displayed brightness is much the same
• Av, P, TV modes - changes to exposure compensation result in darker or brighter display to reflect the requested under or overexposure

Exposure simulation off

• M mode - no changes affect the displayed brightness 
• Av, P, Tv modes - no changes even exposure compensation affect the displayed brightness

If you use Fv mode, then it depends what of the possible parameters you are controlling.

[Tronhard]

Hi and welcome to the forum:

The measure of exposure is given in Exposure Values or Stops, each being a doubling or halving of the light being transmitted.  The camera meters the light from the subject and attempts to give the correct exposure based on what you tell it to change, using the three main control elements:   Aperture (Av), Shutter speed (Tv) and ISO. 

These three form what is called the Trinity of Exposure, they work together to provide the exposure with many variations in settings giving the same exposure, depending on the initial value you set, but with different impacts on other aspects of the image, such as how much is in focus (Av) , camera or subject movement (Tv), or noise and dynamic range (ISO).

The point of Av mode is to allow you to choose an aperture and the camera will choose one or both of the following based on what it things the correct exposure should be: The shutter speed and, If Auto ISO is active, also the ISO value.  In Av mode, if I change the aperture by one stop then the metering system will compensate automatically with one of the other two settings to get the same exposure.  You can reduce that set of variables to one, by turning off auto-ISO, and setting a numerical value, in which case the camera will change only the shutter speed to give the same exposure for any aperture value within the camera's limits.   If you want to fully control both, especially to override the exposure set by the camera then use the EV compensation dial, or shoot in manual M mode.

If you are not familiar with the exposure triangle, then I recommend checking out some You Tube videos on the subject - there are heaps to choose from.