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 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).

Cameras Compared

This chart shows the Nikon D610's default dynamic range performance against a range of competitors - the Canon EOS 6D, Sony Alpha 7 and Nikon D800.

With Active D-Lighting on the default setting of 'ADL Off', the D610 produces a tone curve that is very similar to the D800 and its big brother the D4. Compared to Canon's 6D, the D610 has a slightly more abrupt transition to highlights and clips at about the same point. However, versus the Sony Alpha 7, the D610 clips about 2/3 of a stop sooner.

DR Modes

The D610 offers five settings for Active D-Lighting (ADL) -- Off, Low, Normal, High, Extra High, in addition to an Auto option. Nikon's ADL modes retains 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 extreme ends of ADL -- Off and Extra High -- you can see that highlights are extended by as much as 1 stop.

In the real-world example below, the D610 takes on a high contrast scene showing how ADL has a greater effect on shadow tones than highlights. As you can see in the building windows, shadows are lightened as you step up progressively from Low to Extra High, while highlights are only slightly affected. In our real-world tests, the D610 generally chose the 'Normal' setting when ADL was set to 'Auto'.

ADL Auto
ADL Normal
ADL High
ADL Extra High