Our new 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 cameras) black to clipped white (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' 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 the camera can capture before it clips to white. Shadow range is more complicated, in our test we stop measuring values below middle gray 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.
Active D-Lighting feature
We've already covered the visible effect of Active D-Lighting on a simple test scene earlier in this review, below you can see a graphical representation of the curve produced by each mode. As you can see none of these modes actually extend highlight range, they do improve shadow range somewhat and also the response from middle gray upwards.
Picture Control presets
The graph below shows the dynamic range response from each of the D300's three Picture Control presets (excluding monochrome). As you can see each has a slightly different tone curve but none achieves any better highlight range. Arguably the best overall range (because of its lighter and hence extended shadow range) comes from the Neutral setting.
ISO Sensitivity and Dynamic Range
The D300 has an indicated base sensitivity of ISO 200, sensitivities below this (ISO 160, 125 and 100) are indicated as L0.3, L0.7 and L1.0 respectively. The same is true above ISO 3200 with ISO 6400 indicated as H1.0. As you can see from graph below the compromise at ISO 100 is highlight range which falls just over two thirds of a stop (0.7 EV) short of the highlight range seen from ISO 200 upwards.
From ISO 200 upwards the D300 demonstrates excellent dynamic range, around nine stops in total with a useful four stops of that above middle gray (what we call highlight range). This is a significant improvement over the D200 which had a highlight range of around three and a third EV. Shadow range is slightly better at ISO 400 and 800 because of increased noise reduction (not specifically an improvement in actual range).
|Sensitivity||Shadow range||Highlight range||Usable range|
|ISO 100*||-5.2 EV||3.3 EV||8.5 EV|
|ISO 200||-4.7 EV||4.1 EV||8.8 EV|
|ISO 400||-5.1 EV||4.1 EV||9.2 EV|
|ISO 800||-5.1 EV||4.1 EV||9.2 EV|
|ISO 1600||-4.3 EV||4.1 EV||8.4 EV|
|ISO 3200||-4.0 EV||4.0 EV||8.0 EV|
|ISO 6400*||-3.7 EV||3.9 EV||7.6 EV|
* Non-standard sensitivities
Dynamic Range compared
All of the current crop of 'advanced amateur / semi-professional' digital SLRs (D300, A700, 40D and E-3) deliver around nine stops of dynamic range. The biggest difference is in the balance of the range, the D300 and A700 both deliver around four stops of highlight range (above middle gray) where as the 40D around three and a half and the E-3 around three. Both the 40D and E-3 deliver more shadow range.
|Nikon D300 (ISO 200)||-4.7 EV||4.1 EV||8.8 EV|
|Sony DSLR-A700 (ISO 200)||-4.9 EV||3.9 EV||8.8 EV|
|Canon EOS 40D (ISO 100)||-5.7 EV||3.4 EV||9.1 EV|
|Olympus E-3 (ISO 100)||-5.7 EV||3.0 EV||8.8 EV|
|Nikon D200 (ISO 100)||-5.0 EV||3.2 EV||8.2 EV|
The wedges below 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).
Experience has told us that there is typically around 1 EV (one stop) of extra information available at the highlight end in RAW files and that a negative digital exposure compensation when converting such files can recover detail lost to over-exposure. As with previous reviews we settled on Adobe Camera RAW for conversion to retrieve the maximum dynamic range from our test shots.
As you can see the default Adobe Camera RAW conversion delivers less dynamic range than JPEG from the camera (a more contrasty tone curve and less noise reduction in shadows). The best we could achieve was just under ten stops (10 EV) of total dynamic range - at the optimum ISO 200, more importantly almost a stop of that is in highlights (although with no guarantee of color accuracy).
It's also worth noting that we are indeed plotting both 12-bit and 14-bit RAW modes on the graphs below but that because their results were absolutely identical you can't really distinguish one from the other. 14-bit RAW in theory provides you with more 'data points' between the maximum and minimum brightness (the dynamic range) which could be useful for level-type adjustments.
- ACR Default: Exp. 0.0 EV, Blacks 5, Contrast +25, Curve Medium
- ACR Best: Exp. -1.5 EV, Blacks 1, Brightness + 50, Contrast -50, Curve Linear
WARNING: Although ACR was able to retrieve the 'luminance' (brightness) of wedge steps which were previously clipped there's no guarantee of color accuracy as individual channels may clip before others. This can be seen fairly clearly in the examples below, on the right the negative digital exposure compensation has revealed some more detail but this soon turns into gray as one or more of the color channels clips.
|Adobe Camera RAW default conversion||Adobe Camera RAW with -2.5 EV digital comp.|
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