Yes, the E-system will tend to "under-expose" very slightly--but that's
because of the design intent to protect the highlights. However, unlike
some other brands of digital cameras, the E-system files can be pulled back
up with nasty artifacts in the shadows. Specifically my E-1 has enough bits
assigned to the lower registers to provide boostability without solarization
and awkward noise patterns.
I'm quite leary of dialing in exposure-compensation on the E-1 to counter
this underexposure as I almost always run into two issues when I do:
1. The highlights will get weird out-of-gammut color shifts.
2. The midtones don't have the right tonal separations.
Each camera manufacturer takes the A/D data from the sensor and maps it to a
"response-curve". This response-curve is essentially the "type of film"
being shot. This is PRE-RAW and a vital part of the secret-sauce that
separates one brand from another.
Olympus apparently maps more bit depth into the mid-range than Canon does.
The "common wisdom" that 1/2 of the bits are associated with the top stop is
actually quite false. That would only be true of the bits were totally
mapped in a linear fashion with no bit-bending going on.
When I meter for mid-tones, my mid-tones are more naturally saturated and
smoother than if I "expose to the right" and have to pull exposure during
RAW Conversion.
I also suspect, and this is based on studying Kodak's published response
curves of their sensors, that the sensor itself is not a linear device and
in the case of the E-1, E-300 and E-500, there is a actually a similar
hockey-stick shaped toe and shoulder.
AG
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