Panasonic Lumix DMC-G3 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.
The G3 uses a tone curve very similar to those found in previous Panasonic G-series cameras. It provides 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 a rather abrupt transition from near-white pixels to clipped data. This behavior is a very close match to that of the Samsung NX100 sensor but can't quite compete with a high performing entry-level APS-C DSLR like the D3100 which manages to capture slightly more highlight information. With Nikon's 'Active D-Lighting' engaged, however, the G3 falls much further behind. The D3100 not only surpasses the G3 with nearly 2/3 EV more detail in both highlights and shadows, it also has a gentler roll-of into the highlights, yielding a more gradual transition from near-whites to maximum white.
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.