Panasonic DMC-GF2 Dynamic Range (JPEG)
Our Dynamic Range measurement system involves shooting a calibrated Stouffer Step Wedge (13 stops total range) which is backlit using a daylight balanced lamp (98 CRI). A single shot of this produces a gray scale wedge from the camera's clipped white point down to black (example below). Each step of the scale is equivalent to 1/3 EV (a third of a stop), we select one step as 'middle gray' (defined as 50% luminance) and measure outwards to define the dynamic range. Hence there are 'two sides' to our results, the amount of shadow range (below middle gray) and the amount of highlight range (above middle gray).
To most people highlight range is the first thing they think about when talking about dynamic range, that is the amount of highlight detail above middle gray the camera can capture before it clips to white. Shadow range is more complicated; in our test the line on the graph stops as soon as the luminance value drops below our defined 'black point' (about 2% luminance) or the signal-to-noise ratio drops below a predefined value (where shadow detail would be swamped by noise), whichever comes first.
Dynamic Range compared
The GF2 uses essentially the same tone curve as previous Panasonic G-series cameras, that affords a little over three stops of highlight dynamic range from middle grey to clipped white. The roll-off to the highlights is relatively steep, meaning there can be quite stark transition from near-white areas to completely blown-out areas. This is pretty similar to the Olympus E-PL2 using its Gradation Normal mode, but can't quite compete with the APS-C cameras here (the Nikon's default 'Active D-Lighting On' setting gives it nearly a stop of additional highlight dynamic range). It's by no means a bad performance, but it's struggling to keep up with the NEX's highlight rendition. All four cameras in this comparison behave very similarly in the shadows.
In these particular controlled tests, Panasonic's iDynamic mode doesn't have any obvious effect. In real-world shooting it's relatively subtle too, lifting the shadows (at the expense of extra noise) but doing little or nothing to tame the highlights. This is disappointing compared to what Olympus is achieving with its Gradation Auto setting, which can do a great job of balancing high-contrast scenes without losing local contrast and leaving washed-out images.