JPEG Tone Curves / dynamic range
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.
Note: this page features our new interactive dynamic range comparison widget. The wedges below the graph are created by our measurement system from the values read from the step wedge, the red lines indicate approximate shadow and highlight range (the dotted line indicating middle gray).
At its default Active D-Lighting setting of 'ADL Off', the D600 exhibits a tone curve that is extremely similar to previous Nikon DSLRs like the Nikon D7000 and the more recent D800. This is entirely to be expected and simply shows that Nikon's engineers have 'designed-in' a tone curve for JPEGs that is consistent across its range of DSLRs. What this means in practise is that at identical exposure settings, presented with the same scene, a D600 will give you basically the same picture as a D3200, or a D7000, or a D4. Total JPEG dynamic range is roughly 8.5EV, with about 3.5EV in the highlights, with a relatively smooth 'roll-out' at the top end. Shooting in Raw mode will give you more 'headroom', allowing you to recover those really bright tones that might be clipped in the D600's default JPEG mode.
The D600 offers six different 'Picture Controls', which are essentially color response presets applied to in-camera JPEGs. They all offer the same highlight range but vary image contrast by adjusting the shadow tones to provide either richer blacks or maintain more shadow detail.
The default mode is 'Standard', which yields almost four stops of highlight range from middle gray to clipped white. The 'Vivid' and 'Landscape' options boost image contrast and give deeper shadows, which results in earlier clipping to black. 'Portrait' mode, on the other hand, protects shadows by maintaining detail at the darker end of the tonal range.
The D600 offers five discrete settings for Active D-Lighting (ADL) in addition to an 'Auto' option. Nikon's ADL modes seek to retain highlight and shadow detail in high contrast scenes by combining under-exposure (via a shutter speed adjustment) with manipulation of the image's tone curve.
Comparing the effects of ADL at its extremes - Off and Extra High - you can see that in our studio test scene the highlights are extended by as much as 1 stop EV, albeit with a very abrupt transition between clipped whites and highlight detail. Overall scene brightness is reduced by perhaps 1/3 stop EV in 'Normal', 'High' and 'Extra High' ADL modes in order to expand the highlight range.