Does ISO really mean much in a digital context?

I see that the Olympus OM-D E-M5 doesn't have an ISO mode lower than
200. What does ISO really mean for a digital camera, though?

 

There was always 3 wasn;t there. I remmeber buying HP3 because it was
400 ASA/ISO
I wanted to photograph the stars so reciprocity was a slight concern
to me.
DOF wasn;t relivant but shutter speed was.

In the days of film a lower ASA/ISO meant finer grain and usually less
contrasty images.

Not sure how the modern DSLR is arrcted by setting a low ISO, btu I
still assume a lower
ISO setting is linked to better image quality than a higher ISO could
produce given the same conditions.

 

Sigh. I've just been so conditioned to the idea that you *must* use
ISO 100 for bright, sunny outdoor photography. Heck, maybe I should
just set ISO to "Auto" and think of it no more. :-(

 

Nikon, maybe. Canon, not so much.

-Wolfgang

 

Depends on the specific sensor and how the camera maker has handled
the lowest ISOs in a particular camera. ISO 50 is often handled as
Alan suggests, being "bodged" in simply to give you more latitude in
shutter and aperture selection, but not in all cases. For example,
according to DXO's tests, the Sony A77 has it's top dynamic range and
least noise at ISO 50.

 

Canon usually has the native ISO between 50 and 100, as in "50
does cost dynamic range in the highlights (and is therefore an
extended ISO setting" and "100 doesn't". Which sorta bites
the "150-200" claim.

Nikon, AFAIK, usually start their normal range at 200 ... so
there the claim may work out.

-Wolfgang

 

The Sony R1 had its base ISO at 160, which was where it was at its
best. The next up was 200, then 400, etc..

I get the impression the camera makers know what the best ISO for
their sensor is, but they also know the howls of protest and confusion
and ignorant criticism and salesdriod superstition that would
inevitably follow releasing a camera with a base ISO of say 87 or
163. So they simply stick to the old film-based ISO steps so as not to
alarm the collective brain of the market.