What is dynamic range?

The Photocritic Photography Fundamentals series continues with dynamic range. No, we're not talking about high dynamic range (HDR) photography here, we're going back a step. Dynamic range and HDR are linked but before you can have HDR you need to have dynamic range, and whilst HDR is a tool, dynamic range is a basic principle that underpins photography.

Not just about photography

Dynamic range isn't a concept that's restricted to photography. It's something that we make use of every day, with our eyes and our ears. It's what allows us to hear someone mounting the stairs at the same time as listening to the radio, or be able to see both the sunny and shady areas of a garden simultaneously. Being a 'range' it does have its limits, though: when you're in a dark room that has a brightly lit window, you won't be able to see the view through the window and the room interior simultaneously. One will be over- or under-exposed when the other is properly exposed. The tipping point is the extent of your eyes' dynamic range.

Dynamic range is the maximum difference between bright and dark or high and low that you're able to absorb simultaneously.

So it relates to photography how?

In photography terms, dynamic range is how much difference in contrast your camera is able to record. If you imagine a landscape picture with bright white clouds that are almost over-exposed, the more detail you are able to detect in the shadows is indicative of a wider dynamic range. It follows then that a camera with a wider dynamic range will be of more use than a camera with a narrower dynamic range: it has the ability to record more data and therefore produce images with more detail.

Being able to see highlight and shadow detail is down to dynamic range

Measuring dynamic range

There's no strict measurement for dynamic range in cameras. Sometimes you'll see it referred to as 'EV', sometimes as 'stops'–as in ƒ/stops–and even as 'bits'. In fact, you often won't find it referred to on a camera's specification and you have to go to independent testing and review websites to get a dynamic range measurement.

If you're anything like Team Photocritic and like amassing geeky facts, you'll want to know that the dynamic range of the human eye is approximately 24 stops; cameras have a dynamic range of between ten and 15 stops.

Making the most of your camera's dynamic range

The huge caveat to dynamic range is that you can only make the best of it if you shoot in Raw. Shooting in Raw records vast amounts more data than if you shoot in JPEG and allow your camera to make decisions about what information should be kept and what should be discarded. The bucket-loads of data and the accompanying flexibility that comes in a Raw file is as a result of your camera's dynamic range. Shoot in JPEG and you'll miss out.

TL;DR

  • Dynamic range is the maximum difference between bright and dark (or high and low acoustically) that you can absorb simultaneously
  • Photographically, dynamic range is the maximum degree of contrast that your camera can record
  • Dynamic range can be measured in 'EV', sometimes as 'stops'–as in ƒ/stops–and even as 'bits'
  • To make the most of your camera's dynamic range, you need to shoot in Raw

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