As I first read here, Exposing to the right is an interesting theory. I had to test it.
I posted this at mu-43.com and decided to make it more publicly available.
Coming from a film training background, and shooting in raw ever since my 20d seven years ago; I first learned of Exposing to the right via mu-43.com and pekkapotka.
No way, I thought. That can’t be true. I liked the grit of my old TMAX3200 at concerts in Los Angeles. I always underexposed. It worked.
I was determined to prove someone wrong about ETTR. It turns out, I only proved myself wrong.
I performed this test on a stairway at home.
I did this test handheld, at night, with one light source at ISO 1600. Given my one week of experience with the PEN system so far, I expect lots of chunky grainy noise as the ISO is pushed higher.
Under these circumstances, ETTR shines as the way to shoot RAW for: low light, handheld, high iso. Feel free to click through and check my EXIF data.
And yes, my focus point changed for the correctly metered image, giving a softness to the detail area, but for the purpose of illustrating ETTR, it wasn’t necessary to shoot again.
All of these images have zero post processing other than adjusting 1 exposure to compensate for the over / underexposure in ACR. No sharpening, nothing.
First, exposed to the left:
Just like I learned on my first Olympus OM-1 in grade school. Sometimes you gotta under expose. And the result:

Ah the noise, so familiar.
Second: Exposed like a meter reader must:

Not bad. Not sharp either. But were looking at detail here.
Third: Exposed to the right like a mad scientist:

What the What? That worked?
What, you say? You want detail? OK.
100 percent crop of all three are here for your review
Exposed to the left:

Exposed center:

Exposed to the right:

Just a reminder, to make it more clear.
These were 3 different raw files. I used the same aperture and adjusted shutter speed to expose to the right and the left of correct exposure — according to meter — by one stop.
Each file was then pushed or pulled one stop in Adobe Camera Raw, depending on which direction it needed to go, to return to what normal would have been. The then correctly exposed image remains unmodified.
Proof enough for me. Won’t use it all the time. But this experiment was well worth it for me. Certainly a test worth trying for yourself if you have an Olympus PEN system.