If you are shooting for high dynamic range photos, then your camera should be capable of providing the dynamic range necessary. But how much dynamic range is really needed?
Since the goal in photography is to capture what you see, how much dynamic range can you see? You can see a maximum of about 13 – 14 stops (13 – 14 EV) when viewing any scene. So, you would want your camera to provide something close to this if you hope to capture what you saw. But digital cameras don’t provide as much range as your eyes, and they tend to come in at around 9 EV for the JPEG files they output.
But, if you shoot in RAW, you have an advantage – the RAW files always contain more data than the JPEG files and therefore more dynamic range. Just how much more range is dependent on your camera, but in general it is about 1.0 – 1.5 EV more on the highlight end and 1.0 – 1.5 more in the shadow end, with a total not usually exceeding around 2 EV more dynamic range. Here’s a list of dynamic ranges:
- Eyes: 13 – 14 EV maximum
- JPEG from Camera: 9 EV maximum
- RAW from Camera: 13 EV typical (some are higher and some lower)
- Monitors: about 8 EV
Why is it important to have more dynamic range in the RAW file if the JPEG file doesn’t show it? Because you can post-process to get that extra data in the RAW file to translate to your completed JPEG. Lightroom allows adjustments of shadows and highlights, relying on the extra data in the RAW file to make those adjustments possible. HDR software allows even more adjustment to get you to where you were when you saw the scene and took the photo. If starting with a photo showing 9 EV of range, then software could adjust the RAW file as follows:
- Lightroom adjustments on RAW file: 9.5 EV to 10.5 EV (note that not all photos demand going to 13 – 14 EV based on the amount of dynamic range in the scene itself)
- HDR adjustments on RAW file: up to 15 EV! (that’s more than your eyes can see)
Even though LCDs and monitors can only display about 8 EV worth of image, the HDR process can tone map the wider EV information into that 8 EV space. So hopefully you can see that HDR software will take you to that level where it is as close to what you actually saw in person when you took the photo. It can even push this beyond what you saw to show greater details, but that is getting past the realistic stage and you could risk having a photo look false at that point.
Most reviews of cameras will not let you know how much dynamic range your camera is capable of producing, but there are a few sites worth mentioning that will do the job for you and give you that vital information:
- DxO Mark – see their camera sensor section and find your camera there to see the graph of dynamic range
- DP Review – find your camera review, the newer reviews have tests of dynamic range
Here are some dynamic range charts taken from DxO Mark for the cameras I own:
You can see that the larger and CMOS-based sensor in the Canon T1i DSLR has higher dynamic range. However at the low ISO of 100, it is nearly equivalent with the high-end compact Canon G12. Both are just over 11 EV. But, the G12 drops off faster at the higher ISOs as expected.
The earlier technology of the Canon G9 shows as it starts at a maximum of just under 10 EV – more than a full 1 EV lower than its successor G12.
Going back to what your eyes can see, if you can see 13 – 14 EV does it always mean that there is this much range to see? No. All scenes vary, but the maximum you could see is 13 – 14 EV. A flat scene for example may not have more than a few EV of range (fog, mist, etc.). But, you should plan for reproducing the most range rather than limit yourself to a small range.
With the goal of photography to reproduce what is seen, a good awareness of the amount of dynamic range that you are seeing and that you are capturing is important. I think you would agree that you want to capture as much dynamic range as possible in order to be able to show that in your photos later.
The closer you are in your photos to the range that the eye can see, the better and more realistic your photos will look. Lightroom adjustments and HDR techniques can help push your photos to that level that reproduces what your eyes see. This should always be the goal!