Shooting and Editing Photos Part 2: Capturing High Dynamic Range (HDR) Images
When one shot isn’t enough…
It’s not always possible to capture all the brights and darks of a scene in a single image (see Part 1). Take a picture into the sun and you’ll quickly see the brights are too bright and the darks are too dark, and no amount of Photoshop or Lightroom will ever help. The picture below demonstrates the problem.
The scene holds too much information for my camera to be able to capture with a single shot. Attempting to photoshop this image will result in noisy and muddied shadows with highlights that are lost forever.
In short, quality suffers tremendously when you don’t record all the light a scene has to offer. The answer is High Dynamic Range (HDR) photography.
Here’s what this image looks like as an HDR photo:
The difference is huge! The brights are displayed nicely without being clipped, and the shaded areas are showing details and colors that just weren’t there before. With HDR, it’s suddenly possible to capture ALL the light data a scene has to offer.
Capturing high dynamic range scenes with your camera.
HDR is a two step process: shooting and editing. When you shoot an HDR scene, your goal is to capture as much data as possible by taking multiple pictures of the same thing – some bright, some dark, and one that’s right in the middle. Editing involves merging those pictures together on your computer. The end result is a sort of super-image that allows the viewer to see more brights and darks than a single image would normally allow.
Here’s one of the “too bright” images I used in the above HDR photo:
Everything is horribly blown out except the darkest rocks which actually look pretty good – you can see colors and details in those areas. The final HDR image will include those details.
And one of the “too dark” images:
The rocks and shadows are basically invisible, but the clouds are showing up nicely. The final image will feature colors and details in the clouds thanks to this capture.
Using Auto Exposure Bracketing
The goal of shooting HDR is always the same: capture the light data from the scene. The easiest way to set your camera to do that is by using a feature called Auto Exposure Bracketing (AEB). Depending on your camera, you may be able to bracket 3, 5, or 7 exposures with AEB. Three is usually enough – one dark, one bright, and one that’s just right.
You need to tell your camera just how dark and just how bright your bracketed exposures should be. When I shoot a three exposure HDR I use +-3 EV. That means one photo is shot at -3, one is shot at 0, and one is shot at +3. When I shoot a five exposure HDR I use +-5 EV. These settings work in nearly all situations.
I’ve blacked out the things that don’t matter to show you what a nice setup looks like for an HDR shoot:
- Av (aperture priority) mode is being used
- In this case, aperture and ISO are locked in at f4.0 and ISO 100
- AEB is set to +-3 EV with the “0” exposure set to +1/3 (exposing to the right)
- A time delay of 2 seconds is used
- I am shooting in RAW mode and recording to the memory card
Aperture Priority mode should be used with AEB – this locks in your aperture which keeps depth of field the same for all of your exposures. AEB will automatically change the shutter speed as you take the pictures. The time delay will force the camera to wait 2 seconds then fire all 3 exposures in sequence without further button pressing from you – it’s the best way to avoid camera shake when using a tripod.
After you shoot, ensure you’ve captured all the data by checking the histograms for your darkest and brightest images (check out Part 1 for more on histograms.) Make sure the shadows are exposed well in the brightest shot, and check that the highlights aren’t clipping in your darkest shot. If you didn’t capture all the data, you’ll need to expand your auto exposure bracketing to a wider EV range and reshoot. As you move beyond +-3 EV it becomes more important to use five or more exposures instead of just three. This ensures you’re capturing all the data in a high quality way.
As an alternative to Auto Exposure Bracketing, you can manually bracket your exposures with exposure compensation or full manual mode, but that’s more work and rarely necessary.
Use a tripod. Or don’t…
You’ll eventually blend the images back together in post processing, so it’s important that your exposures are aligned. For the most consistently high quality you should use a tripod, but here’s what to do if you don’t have one handy:
- Set Auto Exposure Bracketing to no more than 5 exposures
- Set your camera for high speed continuous shooting
- Keep your camera as steady as possible and take your series of photos
There is always going to be camera movement when you shoot by hand, but if you can keep the camera steady enough, computer software can do some basic alignment. Here’s a 5 shot handheld HDR exposure from Iceland that worked well:
Why I don’t use my camera’s Auto-HDR feature.
My camera has a built in HDR feature that I never use. Auto-HDR is good in theory; my camera takes the 3, 5, or 7 exposures and merges them together automatically “in-camera”. But by doing everything for me, auto-HDR prevents me from making the creative decisions that drastically alter the look of the final image.
HDR pictures of moving things
Here’s a handheld, +-3 EV HDR shot I took in Brussels, Belgium. It’s dramatic, it’s detailed, and it wouldn’t have been possible without HDR:
The biggest challenge with this shot? The moving people! The editing side of HDR photography gets a lot more complicated when moving objects are introduced, but the important thing for now is the photographic technique is exactly the same.
If you liked this article, take a look at the others in this series: