Dynamic range and Gamut
The Olympus E-620 has a maximum dynamic range of around 12.5EV at ISO 200. Interestingly, though, at ISO 100 dynamic range decreases by 1EV to 11.5EV, which confirms my suspicions that ISO 100 is effectively an extension setting. The fact that the true ‘native’ ISO range is not indicated anywhere on the camera or in the E-620’s handbook is disappointing.
It means, after all, that anyone following the normal ‘good practice’ of shooting at the lowest standard ISO setting available is unwittingly risking burnt-out highlights. With this in mind, I would recommend treating ISO 200 as the minimum ISO setting with the E-620 (and the E-30), at which point, with ESP or highlight/shadow spot metering activated, images contain an excellent tonal range.
This graph shows the brightness values recorded by the test camera when it is used to photograph a stepped graduation wedge. The wedge has transmission values in 1⁄2EV steps ranging from 0 to 12EV.
The camera’s exposure is set so the 12EV section in the wedge has a brightness value of 255. Software analysis of the image then determines the recorded brightness values of all the other steps and calculates the camera’s dynamic range.
Olympus E-620 Gamut
This graphic indicates that when set to the Adobe RGB colourspace, the Olympus E-620 produces JPEG images that exceed the sRGB gamut, and even the Adobe RGB colourspace in some areas, notably in delicate pink and blue tones. As usual, however, the full range of emerald greens in the Adobe RGB gamut are not recorded.
