Learn exactly what dynamic range is with this complete guide.
Often, you’ll find yourself shooting in a situation where there’s lots of light, or in a place where there’s very little. What do you do if you find yourself in a situation where there’s a lot of light and shadows? Things can get tricky at this point, but thankfully something called dynamic range can help you out and assist you in creating the photos you want to get.
How Can Dynamic Range Help You?
Dynamic range refers to the total amount of light the camera captures in a given scene. Low contrast images tend to have an even spread of light over the scene, and no parts are too light or too dark. These are said to have a low dynamic range as there isn’t much tonal difference between the lightest and darkest parts of the image.
If you are shooting an image with lots of bright areas and lots of shadow areas, then it would be a high contrast scene with a high dynamic range as there are large tonal differences between the lightest and darkest areas of the scene.
It’s not necessarily a bad thing to take images like these, but only if it was your intention to take them like this. Knowing about dynamic range will help you take the lighting conditions into account and learn to control the scene to get the shot you actually want, instead of the one where you’re at the mercy of the lighting conditions.
The Histogram is Your Friend
The histogram that you can look at on the back of your camera will tell you if the shot you just took has a high or low dynamic range. As a rule, the far left side of the histogram contains the darkest shadows data, and the far right side contains the brightest highlight data.
If a lot of the image data is gathered to the right and left sides of the histogram, this means that the scene contains both very dark and very bright areas, which means that it has a high dynamic range. This isn’t always a bad thing, though. A lot of photographers like high dynamic ranges because they mean there’s a lot of contrast and pop in the image compared to low dynamic range images, which have a more even, flat light.
If you use live view on your camera, you can look at the histogram in real-time as you are shooting, and take steps to change it if you don’t like what it’s telling you. If you want less contrast, you may have to move your subject to an area where there are less highlights and shadows, and if you want more contrast, try moving your subject to an area that has stronger contrasts between light and shadow.
You may remember that we touched on HDR photography a few articles back, but if you’ve just joined us, or simply forgotten, here’s a brief overview.
HDR stands for High Dynamic Range. It’s a technique that allows photographers to combine multiple exposures into one single image. At its simplest, you would take 3 different exposures of the same scene, at the same aperture and ISO. You would adjust your shutter speed and bracket your exposures so you have one underexposed, one correctly exposed, and one overexposed.
This means that when you combine all three images in a HDR processing program like the one in Photoshop or a stand-alone program, it will take the highlight and shadow information from all three images to provide you with a single image that has the entire dynamic range in it, with no burnt-out highlights and no dark black shadows.
When it’s done well, HDR is great. If you go too far, you end up with really over-saturated, fake looking images. Less is often more!
Camera Sensors, RAW files and Dynamic Range
With the improvements in technology, today’s DSLR cameras are able to capture a far wider dynamic range than they used to. To take advantage of this, you need to shoot in RAW file format, and have access to a RAW file converter like Lightroom to post-process it.
If you shoot a difficult scene, such as a sunrise or sunset in RAW format, you can choose to expose either for the bright sky, or the dark foreground. Exposing the sky or the brightest part of your image is the most important, because as you will see, tonal information in the shadow parts of your image can be recovered.
If your highlights are completely blown out, you cannot recover as much information from them in post-processing. Always err on the side of exposing for the brightest part of your image if you wish to change things in post.
You will find that Lightroom or another RAW converter will have sliders for shadows, highlights etc. Pull up the shadow slider, and you’ll see those formerly dark areas become lighter, but without changing any other areas of your image. You can pull the highlights slider down a little to darken them, but it tends to look strange and obvious if you go too far. It’s always best to move the sliders only as far as you need and no further.
Hopefully, this article will have enlightened you on dynamic range and one of the uses for the histogram. Do you use your histogram to help you make decisions while shooting? Have you tried doing HDR, or adjusting a RAW file for shadows and highlights?
In the next article, we’re going to look at shooting fast-moving objects, and how to do it.