Originally Posted by GSNfan
That image is shot at ISO400, but with -1.3EV and a shutter speed of 1/30. So in other words that is also an ISO 200 photo.
Surely not. It's shot with a higher sensitivity, but with less light shot onto it (which might further affect s/n). I don't think your statement works.
To use a film analogy, if I use faster film, but underexpose, it's still fast film. Correct me if I'm wrong.