Previous page Next page

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 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.

Picture Style options

As with previous Nikons the D5000 uses different tone curves for each of its Picture Control styles, giving more or less contrast. The highlight dynamic range is identical in each but the more contrasty styles, such as Vivid and Landscape, clip to black earlier, to give more punchy images. The similarity to recent Nikons shouldn't be a surprise, since the Picture Control presets can be swapped between most contemporary Nikon DSLRs.

Active D-lighting

A feature that now appears in all Nikon DSLRs is Active D-lighting - a system that modifies metering and adjust contrast at a local level in order to maximize the amount of dynamic range information squeezed into the JPEG file. Because the image-processing side of that equation depends on the image being shot, our test may not reflect the effect you'll see (we've also conducted some real-world tests), but they do help show what the camera's doing.

ISO Sensitivity and Dynamic Range

The base sensitivity of the sensor used in the D5000 is ISO200. There is also a Lo 1.0 mode that attempts to mimic ISO 100 but it's effectively just ISO 200 over-exposed by a stop. The result is that the sensor becomes saturated and clips to white quite easily, limiting that mode's dynamic range. For most applications, you'd be better off buying a neutral density filter if you need slower shutter speeds than ISO 200 will allow.

Beyond ISO 200 the highlight dynamic range remains a fairly stable 4 stops above middle gray. The shadow range appears to increase but this is most likely to be a result of noise reduction dropping noise to below our cut-off threshold. Even so, around 9 EV of dynamic range with 4 stops above middle gray is an impressive result. To put this in context it's worth remembering that the D40 (a well-loved camera that has only just disappeared from the market and was built around a sensor that had already appeared in four generations of Nikon DSLRs - allowing plenty of time for the JPEG engine to be optimized), captured a whole stop less of dynamic range, all of it in the highlights.

Sensitivity Shadow range Highlight range Usable range
ISO 100 equiv. -5.1 EV 3.2 EV 8.3 EV
ISO 200 -4.8 EV 4.0 EV 8.8 EV
ISO 400 -5.1 EV 4.0 EV 9.2 EV
ISO 800 -5.1 EV 4.0 EV 9.1 EV
ISO 1600 -5.4 EV 3.9 EV 9.3 EV
ISO 3200 -5.7 EV 3.9 EV 9.6 EV

Dynamic Range compared

The D5000's performance is certainly in keeping with its peers, capturing four stops of information above middle gray. It clips to black a little earlier than the others, though the bottom end of its tone curve is so similar to that of the Canons, we suspect the results in the shadows will be virtually indistinguishable (it'll clip to black slightly earlier, so is likely to look less noisy). Either way, it's a considerable step forward from the D60 in terms of dynamic range, offering another two-thirds of a stop in the highlights. Leaving Active D-Lighting at its default setting the camera will intentionally underexpose and pull-up the brightness to bring even more dynamic range into your JPEGs if it detects the need for it.

Camera (base ISO)
Shadow range
Highlight range
Usable range
Nikon D5000 -4.8 EV 4.0 EV 8.8 EV
Canon EOS 500D -5.1 EV 3.4 EV 8.5 EV
Olympus E-620 -5.4 EV 3.9 EV 9.2 EV
Nikon D60 -5.7 EV 3.3 EV 9.0 EV
Sony Alpha A350 -4.9 EV 3.7 EV 8.5 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).





Previous page Next page
215
I own it
3
I want it
125
I had it
Discuss in the forums

Comments