Dynamic Range

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.

D-Range settings (ISO 100, 12MP)

Of course Dynamic range is the S5 Pro's big selling point, and we were very interested to see if the reality could live up to the marketing hype. The S5 Pro now offers seven D-Range settings (the S3 Pro had four) including the default 'Auto' setting, from 100% to 400% (2 stops greater). I'm not sure how much of an advantage it is to be able to choose your D-Range in such fine steps and I imagine most users will leave it set on Auto most of the time unless they are looking for a particular effect (a natural consequence of increased DR is a loss of contrast) or need to increase continuous shooting speed. The auto setting tends to default to 400% unless shooting on a cloudy day or indoors in dull light.

The S5 Pro's screen isn't really good enough to show the subtle differences between one setting and the next, and the safest option is to shoot raw and use the FinePix Studio or Hyper-Utility to set the D-Range when you've got a proper screen to work on (raw files contain all the S and R pixel information at all settings except 100%).

So does it work? The answer, as the graphs, charts and examples below show is emphatically yes, and it seems to work better than the S3 Pro. There is a clear 2.0 EV difference in total dynamic range between the 100% and 400% settings, and it's possible, with careful exposure, to get almost 12EV out of a JPEG - this puts the S5 Pro streets ahead of all its competitors. As the examples at the bottom of the page show the extra range does give you considerably more exposure latitude than you would normally expect from a digital SLR, particularly if shooting raw.

It's also nice to see that the higher D-range options have a smooth, clean roll-off in both highlights and shadows and it really is rare to see harsh clipping at all in well-exposed S5 Pro JPEGs. Kudos.

Film Simulation modes (D-range AUTO)

As the graphs below show the slightly different tone curves applied to the various film modes have a direct impact on the dynamic range of the final result, with F2 in particular sacrificing over 5.0 of dynamic range to get 'punchier' more contrasty results (all the more reason to use it carefully unless you're shooting raw).

ISO Sensitivity and Dynamic Range (D-range AUTO)

As is to be expected the dynamic range falls as you increase ISO - this is totally normal, but in the special case of the S5 Pro it's mainly because at a certain point (over ISO 1000) the smaller R pixels (which have very low sensitivity) are no longer used. Since you're unlikely to be shooting anything with a very wide dynamic range at ISO 1250 or over this is unlikely to be an issue.

Dynamic Range compared

The graph below really does speak for itself; the S5 Pro's dynamic range advantage over the Canon EOS 5D and Nikon D200 is clear, and substantial.

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).

D-Range settings compared (JPEG)

1/285s F9 ISO100, -0.3 EV	50% crop
D-RANGE 100% (maximum)
D-RANGE 400% (maximum)

The example above shows clearly that the difference between 100% and 400% is the difference between clipped highlights and non-clipped highlights. This is exactly why the S5 Pro and its predecessor have found their niche with wedding photographers (trying to get a white wedding dress and a black suit correctly exposed with most cameras is a trial).

RAW headroom

Experience tells 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.

The S5 Pro is unusual in that there is very little 'extra' dynamic range in raw files - a tribute to the excellent in-camera processing that already - in best case scenario shooting conditions - squeezes 11.8 EV into a single shot.

The most we could achieve using Adobe Camera RAW was a total dynamic range of 12.1 EV, interestingly this was using the 'Auto' setting, so though it's not at all well optimized to get the best resolution out of S5 Pro files, ACR 4.1 has no trouble getting the best dynamic range. It's worth noting (as shown at the bottom of the page) that there is a little more headroom in the highlights than the auto setting uses, but this contains nothing really usable (channel clipping means a strong magenta cast appears in all highlights). Even the auto setting added a small, but manageable amount of magenta to highlights (and with a little tweaking you can recover a surprising amount of highlight detail with no color issues).

• ACR Default: Exp. 0.0 EV, Blacks 5, Brightness +50, Contrast +25, Curve Medium
• ACR Auto: Exp. -0.35 EV, Blacks 0, Brightness 0, Contrast 0, Curve Medium

The example below shows just how much exposure latitude you can - if needed - get out of the S5 Pro's raw files if you exposure for the shadows (i.e. slightly over expose compared to when using any other SLR). The JPEG shows totally burnt highlights but ACR manages to pull back detail that would simply be lost forever with most cameras. Pulling back the highlights in this way does eventually new problems, with a magenta cast appearing if you go too far, but with a little experimentation it's possible to get a huge dynamic range - over 12 EV - out of a single exposure, which is pretty impressive stuff.

Out of camera JPEG	100% crop
ACR 4.1 (RAW) - Auto Setting (exp -0.7)	100% crop
ACR 4.1 (RAW) - Manual Setting (exp -2.6)	100% crop