T8i: Let's assume I'm in Manual Auto ISO, too dark and too light exposure issues

[stevet1]

Let's assume I'm in Manual with Auto ISO.

The scene is stationary, so there's no danger of motion blur.

I meter the scene and it hits 0. I'm properly exposed, but I think the picture is a little too dark or too light for my tastes.

My focal length is around 50 or 60mm, and my shutter speed is up around 1/250, so I've got some wiggle room before I risk camera shake.

My ISO is around 320-400, so I'm not too much danger of introducing objectionable noise.

The conventional wisdom to darken or lighten my picture by 1/3 or 2/3 of a stop is to use exposure compensation, whIch In Manual plus Auto ISO is going to raise or lower my ISO.

Why should I do that instead of just slowing or speeding up my shutter speed by 1/3 or 2/3rds of a stop?

On my camera (a T8i), using exposure compensation requires two simultaneous actions - pressing the set button whiie turning the main control wheel.

Changing the shutter speed only requires the one action of turning the control wheel.

Steve Thomas

[stevet1]

I expressed the same puzzlement back at the end of 2025 on a thread entitled, "T8i ISO too high".

Back then, I wrote,

"

In response to SignifDigits

‎12-31-2025 12:50 PM

"SignifDigits,

In researching this issue, I discovered that it is not an uncommon phenomenon.

If you do a Google search for Overexposure and Auto ISO, you see entry after entry of people who experience the same thing. I even read one person who said that with Auto anything, Canon lands on the side of caution and has a tendency to lighten things up as opposed to underexposing."

Steve Thomas

[stevet1]

"SignifDigits,

In researching this issue, I discovered that it is not an uncommon phenomenon.

If you do a Google search for Overexposure and Auto ISO, you see entry after entry of people who experience the same thing. I even read one person who said that with Auto anything, Canon lands on the side of caution and has a tendency to lighten things up as opposed to underexposing."

Steve Thomas

[Waddizzle]

Despite what metering in a DSLR shows, the cameras seem to have +1/3 Ev of compensation baked into them.  

This behavior does not seem to be used in the full frame R Series bodies. Dialing the small amount of negative compensation results in a photo that looks a little under exposed. 

[ebiggs1]

"There’s even a name for it. ETTR."

That's not "baked" in unless you the operator bake it.

[kvbarkley]

I know I have seen him discuss it elsewhere, but Ken Rockwell seems to dial in a -1/3 ev compensation on his Canon DSLRs:

https://www.kenrockwell.com/trips/2012-04-slo/index.htm