Does the E-10s split prism design cause a “loss of light”?
Yes, the E-10s split prism diverts approximately 50% of the light away from the CCD, hence the ratings. The CCD is calibrated for normal 100, 200, 400 ISOs in non-prism cameras, and the original E-series prototype had ISO ratings of 50, 100, and 200. Olympus later boosted these ratings to 80, 160, and 320. Some theorize that this sensitivity “bump” raised the level of noise in E-series images. Does this make the viewfinder dark? No. Even in low lighting. Believe it or not, it’s actually as bright if not a tad bit brighter than my standard-mirror film SLR. How does that work? I don’t know!
