In Parts One and Two, we discussed what dynamic range is and why dynamic range numbers only tell you a part of the story.
It’s also worth noting that JPEG files don’t even use a camera’s full dynamic range; they typically include only nine or so stops of DR. So, if dynamic range numbers don’t tell you much about a camera’s image quality, and your JPEGs only use a portion of it anyway, why do we try to examine cameras’ dynamic range, and of what use is it?
Which HDR: wide DR display or just wide scene DR?Unhelpfully, the term ‘High Dynamic Range’ can refer to two things: tone-mapped photos that try to convey a wide DR scene on an SDR display, which develop a rather ‘distinctive’ look if there’s an attempt to include too wide a dynamic range, or wide DR images shot for playback on HDR displays, which can present this wider dynamic range in a more realistic, life-like manner. |
When you’ve hit the JPEG limit
The most obvious case when you want more dynamic range is when you’re trying to photograph a scene that has more than ~9EV of dynamic range. The standard JPEG tone curve is designed to work for most photos, but sometimes you want to capture something like a sunrise or sunset that has more tones than the JPEG handles, and either the highlight detail clips or the shadow detail disappears to near black.
This is a good argument for shooting Raw, which gives you the option to reduce the exposure and brighten the shadows of your files to cope with dramatic lighting. In these circumstances, a camera with wider dynamic range will provide more usable latitude, especially in the shadows.
But the era of the ~9EV JPEG could be coming to an end.
Displaying wide DR images
The latest HDR displays can show a wider range of tones than conventional ‘standard dynamic range’ (SDR) monitors and TVs. They provide an opportunity to represent scenes with brighter highlights and less clogged-up shadows in a more naturalistic manner, meaning they can show dramatic sunrises and sunsets, or sunshine glowing through the petals of a flower, without the strange, circus-like look that exaggerated ‘HDR’ imagery can show. As HDR displays, 10-bit file formats that make the most of them and editing software that understands them become more commonplace, the ability of a camera to capture a wider dynamic range may become increasingly valuable.
Overall, then, while one shouldn’t use DR numbers as a catch-all summary of a camera’s performance, dynamic range itself remains an important part of image capture technology, and one that looks to become even more useful in the near future.
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This article comes from DP Review and can be read on the original site.
