topic Re: T8i: Let's assume I'm in Manual Auto ISO, too dark and too light exposure issues in EOS DSLR & Mirrorless Cameras

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

stevet1 — Sun, 25 Jan 2026 03:56:39 GMT

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

Re: Let's assume I'm in Manual..

rdominy — Sun, 25 Jan 2026 03:23:55 GMT

You can change your shutter speed, but the camera will increase or decrease the ISO in response to match its metering. That shouldn’t change what you see in the viewfinder. If you feel the metering is off (too light or dark), you need to change the exposure compensation.

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

Waddizzle — Sun, 25 Jan 2026 05:02:06 GMT

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

Good question. Excellent question!

I don’t think that there’s any objective answer to it. The best answer probably falls somewhere between personal preference and shooting conditions. But, I will tell you how I resolved this situation with DSLRs. I use a different strategy with MILC bodies

I have used several Canon DSLRs released since the late 2000s. The Canon DSLRs seemed to have a small amount of exposure compensation baked into the metering system. I began to have this suspicion once I began shooting in M mode with ISO Auto. Canon bodies seemed to slightly overexpose. This could give better performance in shadow areas, but it could also raise the risks of saturation in the highlight areas.

[EDIT] I “confirmed” that suspicion with a light meter.. At least so I thought. Always doubt your conclusions.

So, I dialed in AEC at -1/3 EV for my exposure setting. I used to compensate for this apparent bias using my LR import profiles. I felt getting right in “in camera” gave me better results.

MILC bodies. I have used the RO. I wound up buying the R6ii. I no longer have -1/3 EV if AEC dialed in.

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

stevet1 — Sun, 25 Jan 2026 05:25:42 GMT

Waddizzle,

You wrote, "The Canon DSLRs seemed to have a small amount of exposure compensation baked into the metering system. I began to have this suspicion once I began shooting in M mode with ISO Auto. Canon bodies seemed to slightly overexpose."

I've been having the same suspicion. At first I was blaming the use of Auto White Balance. Then I started blaming the use of Aperture Priority. Now I'm wondering if it's not just inherent in the system.

Steve Thomas

Re: Let's assume I'm in Manual..

stevet1 — Sun, 25 Jan 2026 05:29:26 GMT

rdominy,

This makes sense. My scenario would only work if my ISO were fixed.

Steve Thomas

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

Waddizzle — Sun, 25 Jan 2026 05:40:10 GMT

For numerous subjective and objective reasons, Canon DSLRs have had a reputation for not having the best performance in the shadow areas. Upping the exposure slightly reduces that noise, but it also increases the potential for saturating the highlights. I am willing to trade under exposed shadows instead of over exposed highlights.

Re: Let's assume I'm in Manual..

ebiggs1 — Sun, 25 Jan 2026 16:35:10 GMT

"... I'm in Manual with Auto ISO." ... "This makes sense. My scenario would only work if my ISO were fixed."

You are not really in 'Manual ' mode are you? A pseudo manual mode perhaps but not manual.

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

ebiggs1 — Sun, 25 Jan 2026 16:43:14 GMT

"The Canon DSLRs seemed to have a small amount of exposure compensation baked into the metering system."

Not buying that for a second. There are way too many variables to make a statement like that. Wide aperture lenses, exposure mode how much contrast is on the scene or how bright, WB settings, etc., and way many more.

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

Waddizzle — Sun, 25 Jan 2026 16:49:39 GMT

“ I've been having the same suspicion. At first I was blaming the use of Auto White Balance. Then I started blaming the use of Aperture Priority. Now I'm wondering if it's not just inherent in the system. “

I am certain that books were being cooked. Test it for yourself. Take a variety of shots with -1/3 Ev of AEC. I am not concerned about darker areas in the photo. Colors seem more true to life.

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

Waddizzle — Sun, 25 Jan 2026 18:23:34 GMT

“ Not buying that for a second. There are way too many variables to make a statement like that. Wide aperture lenses, exposure mode how much contrast is on the scene or how. “

It seems to be baked into the cameras. You can see signs of it in histograms. There’s even a name for it. ETTR.

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

stevet1 — Sun, 25 Jan 2026 19:39:03 GMT

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

Back then, I wrote,

"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

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

Waddizzle — Sun, 25 Jan 2026 21:35:11 GMT

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.

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

ebiggs1 — Mon, 26 Jan 2026 15:23:29 GMT

"There’s even a name for it. ETTR."

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

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

kvbarkley — Mon, 26 Jan 2026 15:44:38 GMT

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