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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).

Cameras Compared

Interestingly, the Coolpix A's tone curve is rather different to those employed by Nikon's DSLRs. The curve is an elongated 's' shape, giving a slightly lower-contrast response than the DSLRs but incorporating more tonal range in the highlights.

Color Modes

The Coolpix A uses a slightly different tone curve for each of its Picture Control presets. As you might expect, the Neutral and Portrait settings have slightly less contrast, while the Vivid setting has most. The camera allows you to tweak the behavior of each preset and displays each preset on a grid, showing their contrast and saturation in relation to one another.

Active D-Lighting

The Coolpix A makes use of the Active D-Lighting system that Nikon has used in its DSLRs since the D300. Depending on the setting applied, this will reduce the exposure to increase the amount of highlight range captured. The camera then analyses the image and selectively brightens it, so that the final output represents the expected overall brightness, but with more tonal detail in the highlight regions, balanced shadow regions and a retention of local contrast.

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Total comments: 6

Just bought one from BH Photo including the electronic viewfinder for $490.00. Quite a camera for that price.


Frankly, how you can let yourself be disappointed by autofocus when the camera has manual focus is beyond me. Pre-focus and snap away!


I see what looks like the same Coolpix A offered on for about 1000 dollars and for about 650 dollars. The latter is marked "import". Anybody able to explain the difference?


Any deeply discounted price indicates that it is likely an import. Nikon will not service it if you have a problem. You can take the risk, but if you experience a problem do not give Nikon a bad review. Don't say I knew but...

Also note that you will not be able to download firmware updates for the camera. I would not touch an imported camera. If you want to save money, then wait about a year and hope they are coming out with a newer version - and that is when they offer great discounts. For example, Nikon just dropped the price on the camera for only $699.


That price!

Comment edited 20 seconds after posting

Over $1,000 for a DX sensor with a fixed 28mm lens? I get that it is for "enthusiasts", but that seems like quite a bit of enthusiasm to me.

Total comments: 6