"HDR" | How to Create High Dynamic Range Images
August 12, 2018.
Multnomah Falls, Oregon | Multiple-exposure HDR | Nikon D750 + Nikkor 18-35mm f/3.5-4.5G
WHAT IS "HDR"?
The term "HDR" stands for "high dynamic range". HDR is a form of photography where a photographer will take multiple exposures of the same scene going from light to dark or dark to light, and then combines them into one image using specialized post-processing software. That single image can then be manipulated within the program to contain information from all of the exposures, taking the best parts from each. The goal is to take a high contrast scene where very bright highlights and dark shadows are present, and retain details and proper exposure in both.
For example maybe you've found yourself in front of a beautiful sunset landscape, took the picture, but had a hard time capturing what your eyes can see. Your camera either exposed for the highlights which left your shadows too dark, or it exposed for the shadow areas, which blew out your highlights and washed out the sunset completely. HDR photography is one way of overcoming that hurdle.
Some newer cameras have an HDR feature built in. Most will allow you to shoot up to three frames of varied exposure and will automatically combine them in-camera to give you a high dynamic range image. Unfortunately, some models will only allow you to export such an image as a JPEG file, which may limit the post-processing options for the more demanding photographers. If you want more control and you like my results, here are some tips I can offer you;
Munson Creek, Oregon | Nikon D750 + Nikkor 18-35mm f/3.5-4.5G
While the following tools are not absolutely necessary for creating HDR images, they will certainly make your job easier and you will yield better results when you use them. HDR photography demands a little bit of extra work to get the best results, and that means you may have to carry extra weight and exercise some patience. Here's what you need;
Make sure you use a quality-built, sturdy tripod that is rated for the weight of your camera + lens. It also helps if the tripod allows you to position the camera + lens at odd and low angles. You want to have options when it comes to framing your shot, because composition is important.
I often find myself being lazy, so I don't always bring my tripod on a hike, or even a short walk. I simply hand-hold the camera as still as possible to get those five or nine exposures, but I always regret it when I get home.
Unless you're super-human, it is impossible to remain as steady as a tripod for all of the exposures. Usually I have to use higher ISO values in order to be able to use higher shutter speeds to keep motion blur at bay, and I find myself shifting to one side or the other during the exposure sequence, even if just by a fraction of an inch. That means the images are not lined up perfectly.
While post-processing software has the ability to align the images to a good degree, it's not always going to be perfect. You will end up hurting the image quality hand-holding, especially with the longer exposures that require a very slow shutter speed. Using high ISO to get those last couple of overexposed shots means that you sacrificed some fine details you can't get back. In other words, don't be lazy and bring a sturdy tripod with you.
REMOTE SHUTTER RELEASE
Again, a remote shutter release is not an absolute requirement for HDR, but it can help prevent you from introducing camera shake, and therefore motion blur into your photos. You want to produce the sharpest results possible for the best results, and that means as little movement as possible.
Some cameras have a timer and when the camera is also set to the "bracketing" option, it will automatically take all the exposures once the shutter button is pressed and released, without you having to touch the camera again (this is a Nikon feature and I am not sure if other camera makes have this option as well).
I am a lazy photographer and I often just use the timer. I set it to 10 seconds to give the camera and tripod plenty of time to stop any vibration that may be caused by my touching the shutter button and pressing it. It also gives me enough time to get away from the camera and tripod, so that I don't accidentally kick or nudge them as I'm getting up.
However, if you are shooting in the dark (star trails for example, etc.), if you want to control the exposure time of your bracketing sequence instead of leaving it to auto, if you want more bracketed images than your camera model allows in auto mode and if you require a longer exposure than 30 seconds, a remote shutter release is a must, so that you can use your camera in "bulb" mode. Bulb mode with a wired or wireless shutter release will allow you to expose for many minutes at a time.
HDR POST-PROCESSING SOFTWARE
There are several HDR post-processing programs available, some more expensive than others. You may need to download trial versions of them and try them out, so that you can decide which one is right for your needs. More expensive doesn't necessarily mean "better" and that is why using a trial version for a time is the best way to make up your mind.
Personally I like to use Photomatix Pro and Easy HDR. Both are good programs, but I do favor Photomatix Pro. I'm not going to sugar-coat it,... it will take some time to get familiar with each program and get the best out of it. Patience is your friend.
If you have a subscription to Adobe Lightroom Classic and/or Photoshop, these two programs give you the possibility of creating HDR images automatically. Both can do a good job, but personally I think Photomatix Pro and Easy HDR do it better.
Here are links to some HDR programs in no particular order:
All of these programs should have a 30 day free trial that you may download and use. As you can imagine, it would take me forever to walk you through each of these programs step-by-step. Luckily I don't need to! All of them should have tutorial videos available on their websites for your viewing pleasure, and even if you don't watch any tutorials, most of them will be easy enough to figure out on your own.
Joshua Tree National Park | Nikon D750 + Nikkor 18-35mm f/3.5-4.5G
Let's assume that you have found the perfect subject for your first HDR image and you want the best results possible. You have your tripod, camera, lens and remote shutter release ready, but there is still the matter of settings.
If your camera contains this feature, it makes the process much easier than having to figure out each exposure yourself. Consult your camera manual for instructions on how to turn it on and how to customize it to your preference. Most manufacturers have online manuals that explain the process step-by-step.
IF YOU OWN A NIKON DSLR SUCH AS THE D750
Push the "Menu" button on your Nikon camera and go to the "Custom Setting Menu", scroll down to "e" for "Bracketing/Flash" and press the "OK" button to enter the menu. Scroll down to "e6" for the "Auto bracketing set" and select "EA Only". You may then exit the menu.
Next, look on the left side of your camera body. You will see a button marked as "BKT". Press the button, hold it down and look on the LCD screen. You will see the markings "0F" on the left side of the screen and "0.3" on the right side of the screen.
While holding down the "BKT" button, use the rear command dial to change the number of bracketed images you wish to take. For example, you may select between 3 to 9 frames on the D750, or 2 to 9 frames on a D850. Your options can vary with each camera model. You may notice that as soon as you turn the rear command dial, a small "BKT" icon will appear on the bottom of the LCD screen to let you know that you have turned bracketing on.
While holding down the "BKT" button, use the front command dial to change the value of the exposure compensation, or if you are happy with 0.3, you may keep it there. The smaller the number, the smaller the difference you will see in exposure between your selected number of bracketed shots. The larger the number you select, the larger the exposure difference will be between each shot. You may choose 0.3 (smallest difference), 0.7, 1.0, 2.0 or 3.0 (largest difference).
You may need to experiment with the number of shots and amount of exposure compensation to determine what works best for you. Personally I usually shoot 9 bracketed shots with exposure compensation set to 0.7, but to each his own!
If shooting with bracketing turned on, Aperture Priority is my personal mode of choice for HDR photography. I can control the aperture and ISO, while the camera determines the shutter speed needed for each exposure.
If your camera does not have a bracketing option, you can use Manual or Aperture mode and adjust the exposure compensation in Aperture Priority, or shutter speed in Manual mode between shots yourself. Your goal is to create between two and nine shots that vary in exposure from dark to light, so that you capture all the dark, mid-tone and bright details in your scene.
If you are shooting in Manual mode and doing the bracketing manually, you do not need to worry about selecting a metering mode, because your ISO and aperture should be constant while you adjust the shutter speed between shots yourself.
If you are shooting with an auto bracketing mode in aperture priority, you should set your metering accordingly. The metering option you select will depend on the camera make you own.
Newer Nikon cameras have options between Matrix, Highlight-weighed, Spot and Center-weighed metering. Personally I prefer to use either Matrix or Highlight-weighed metering. Matrix metering will take the entire scene into consideration and expose accordingly, while highlight-weighed metering will prioritize the highlights in a scene.
Your aperture settings will depend on your preference for how much DOF (depth of field) you need or want. For landscapes, narrow apertures are ideal if you want most (if not everything) in your frame in focus.
Depending on how wide your lens is and what type of camera you're using, you will have to figure out what aperture will produce the best combination of sharpness and DOF. Personally I like to use f/16 with my D750 + 18-35mm f/3.5-4.5G and I like to use f/8 or f/10 at the most with my IRIX 11mm f/4. Any aperture beyond that, and I run into diffraction, which will end up giving me more depth of field, but softer, less sharp results.
Depending on your camera make or model, ideally you want to use your base ISO, which produces the best image quality. Why? Because these values contain the most dynamic range and least amount of noise.
Some models may have a base ISO of 64, others will have a base ISO of 100 or 200. Whatever it is, that is what you want to stick to. The less noise is introduced into your images during the multiple exposure, the more detail you will be able to capture in your scene.
Shooting in RAW format (preferably 12 or 14bit RAW, if your camera model allows it) is not a requirement, but it will yield you the best results possible. Why? Because it gives you more control over what you upload to your HDR software when you're done.
You can choose to upload the original RAW files to your program of choice, or you can process the RAW files in your favorite editing program by adjusting the sharpness, white balance, saturation and so forth, export your final edit as the highest quality JPEGs or TIFFs, and upload them to your HDR program.
SOOC (or "straight out of camera") JPEGs are a lot less flexible in some ways during post-processing, because your in-camera color and white balance settings get baked into them forever. If you over-sharpened or over-saturated your photos in-camera, you won't be able to pull back on those settings after, and you are stuck using what you have. The results may still be great in the end, but they probably could have been better!
The Grand Tetons in Early Morning Light | Nikon D750 + Nikkor 18-35mm f/3.5-4.5G
PROCESSING YOUR PHOTOS
After a day of shooting, you come home with a loaded SD card. Full of anticipation, you download your RAW files, open up your software of choice and enthusiastically start working on your shots. Suddenly your software asks you whether or not you want to remove "ghosts". Huh? What does this mean???
When you take a bracketed sequence of a bridge with people walking by, or you take a sequence of a forest with a breeze blowing the leaves around, naturally each exposure will be just a little bit different from the one before it.
When you combine them into one image, you can either choose to have these differences overlap each other equally, overlap at a custom-set percentage, or you can choose one of your photos as the main exposure, which means those differences from all your other exposures will be erased. Sometimes neither choice will seem perfect and you'll have to make a compromise. Experiment and see what you prefer.
Once you've gone past the shot selection, alignment, ghost removal and so forth, your bracketed sequence will be combined into one image. You'll see that whatever program you choose to use, it will have sliders that change different aspects of your image. You will also see that the program contains some presets. You can choose to start with a preset that looks best to you, or experiment on your own to see what each slider does. In my opinion it is best if you play around with your image until you see a result you like. Sometimes that might take anywhere between 10 to 30 minutes until you have explored all the options!
Your very first HDR images might not be the best, but the more you use the program, the better you will become, and your results will improve over time.
Most post-processing programs will give you the option of viewing the histogram. Paying attention to the histogram can be of value in almost any type of photography. It can tell you whether your final image contains overexposed highlights, or underexposed shadows.
Since we aim to retain details in the shadows and highlights, we want to make sure that the histogram is not leaning too far to the right (overexposed), or too far to the left (underexposed). A more centered histogram is ideal, but don't expect every photo to produce a perfect histogram. As long as it is not touching one wall or the other to a large degree, you're probably OK. Use your eyes to judge the image and use the histogram as a useful guide if need be.
If you do not have a color-calibrated monitor, the histogram can be even more useful. Why? Because your monitor may not be showing you the true color values of your photos. While the image might appear very bright to you, other people viewing your work on their monitors may see a much darker image on their side, and vice versa. The histogram may give you a clue as to how color-accurate your monitor really is.
SAVING YOUR IMAGES
When I'm finished with all of the HDR adjustments and I'm ready to export my file, personally I prefer to save it as a high quality 16bit TIFF, so that I can then import it into my processing software of choice (in my case that's usually DxO PhotoLab Elite, Photoshop, or Lightroom) to make additional corrections.
Specialty HDR programs are usually limited in certain ways, so I prefer to do my sharpening, contrast, saturation, distortion correction and so forth with a more capable software. It's also what I prefer to use to export the image to JPEG. You don't have to do what I do, but it is an option.
Banska Stiavnica, Slovakia | Nikon D750 + Nikkor 85mm f/1.8G
HOW MUCH IS TOO MUCH?
HDR photography gives you a lot of power and flexibility as a photographer and artist. Beauty will always be in the eye of the beholder, therefore it may be hard to gauge what people will find aesthetically pleasing and where exactly that aesthetic will reach its limits.
As far as I'm concerned, my goal in HDR photography is to reveal all the fine details without destroying that great light-induced 3D volume of the scene. I don't want to even out the shadows and highlights to such a degree, that it flattens the image and begins to resemble a 2D drawing or painting. I don't claim to always succeed, but that is what I generally strive for.
You may find that some people are opposed to anything HDR, while others might love that extreme HDR look. You just never know what type of reaction your photo will elicit from one person to the next. It's my opinion that the more natural it looks, the more compliments you will likely receive. In the end it's all about what makes YOU happy. Have fun with it, experiment and keep shooting!