Welcome to the article on HDR. In this article you’ll learn all about HDR images – What are they? How to set various settings in your camera to click HDR image(s)? How to take HDR shots? Step by step process to produce final HDR image and the important Do’s and Don’t’s of producing HDR images.
1. What is HDR?
HDR stands for High Dynamic Range. Technically speaking, HDR is the difference between the lightest vs darkest colour tone in a photograph. Producing an HDR image means the range of contrast and colours of a picture are enhanced. To understand it more, let’s understand briefly about a few concepts.
Highlight area in a photograph is the area that is lit well (or bright). Shadow (or Lowlight) area is the area that isn’t lit well (or dark). Contrast is the difference between the highlights and shadows in the image. Higher the contrast the difference between these elements is projected well. Lower the contrast means they both don’t differ much and end up looking almost merged or similar.
Similarly, the color tones appearing in a photograph of a usual shot (read as, single click) fall in a range lower than an HDR image.
HDR picture is not shot by a single click of the camera. Typically, 3 (or 5 or even more) shots are taken and post-processed to come up with a final HDR image. The main difference across these shots is exposure. To be able to enhance the dynamic range, the same scene (frame) is captured in different exposures. It ranges from keeping it in low exposure, (almost) correct exposure, and high exposure in several steps/F-stops. In a way, this is also called “Bracketing”.
2. How to set HDR mode in Camera?
The first step to create an HDR image starts with setting your camera to HDR mode.
If you own an iPhone (or iPad), the default camera application has the option to enable “HDR Mode”.
If you own an Android phone, check if the default camera application has this option. If not, you can download a slew of camera applications (such as ‘HDR Camera’) which support taking HDR shots.
If you own a compact or bridge or any other camera, check the camera manual as to how to enable HDR mode.
Finally, if you own a DSLR or Mirrorless camera, the menu settings will help enable HDR mode. I’ve given below the menu settings to enable HDR in a Canon DSLR. Other models/manufacturers have similar settings.
This button on the top left is a shortcut button to enable HDR and other options. Once you click it, select the HDR button on-screen as indicated by the arrows.
The same setting can be invoked from the usual menu screens as given in the picture above. The “HDR Mode” submenu option is the one we’re looking for.
Both the menu options indicated in 2 images above, will lead us to the menu indicated in the picture above. Let’s understand these options briefly.
- To enable the HDR mode, you’ll be asked to choose “Exposure Variation” across the shots, as shown in the menu above. EV value must be set in conjunction with a number of bracketed shots. I typically use 3 brackets and +/- 2 EV. This is found to work better. If the number of brackets is 5 or more, +/- 1 EV works well. +/- 1 will take the shots with less difference in exposure across shots vs +/- 3 will show more difference.
- Secondly, the effect menu option shows various choices as shown above. This option is important only if you’re letting DSLR itself create the final HDR image. Else if you’re going to use Photo Editing Software (like Adobe Lightroom) to create an HDR image, then you can ignore this option. “Art Vivid” is a neutral choice here. “Art Standard” is very subtle. “Art Bold” is way too sharp, may not look good. “Art Embossed” feels like a film negative style. I always leave it as “Art Vivid” and use Lightroom to post-process.
- “Continuous HDR” menu option: I use this option wisely – if I plan to take quite a few HDR shots consecutively, I set it to “Every shot” or if I plan to take HDR shot just once I set it to “One shot”.
- “Auto Image Align”: Again, it’s needed only if you use the HDR image created by the DSLR. It instructs the camera to handle the alignment of all exposure shots automatically. Don’t bother if you plan to create an HDR image through post-processing yourself.
- “Save source images”: To post-process yourself, it’s just to keep source images. Only then you can use those to create HDR images through photo editing software. Else, if you use camera created HDR shot, you can choose to keep source images as well or not.
You need to remember a few points before taking HDR shots.
- Since the camera is going to click more than one shot in a short interval, ensure that there wouldn’t be any moving object in the frame. Else it’ll form ghosting effect (more about it later).
- You need to ensure the camera is held steadily while clicking. If held in hand, ensure the shutter speed is high enough to not cause shake and ensure not to shake the camera while pressing the shutter button. If you must take HDR shots during low light situations (E.g., sunset), please ensure to mount the camera in a tripod. This will prevent shaky shots.
- The focal length and depth of the field must remain the same across all the shots. Thus, do not attempt to zoom in or out during the shots. Similarly, leave the aperture and ISO the same as well. When the camera takes the HDR shots, it’ll change mainly the shutter speed across the different (bracketed) shots. If you’re taking the shots manually by yourself, remember to do the same.
3. How to take shots for HDR?
After setting up the camera as described above, press the shutter button just once as you do for a normal (non-HDR) capture. Now the camera will take as many shots as many numbers of bracketed shots you’ve set up for. How fast or how slow will the camera take these shots in the sequence depends on the shutter speed you’ve set up, the number of bracketed shots to be taken, and the range of F-stops setup through EV setting.
This will produce source images of all shots. They could be RAW files or JPEG as per your setting for an individual (non-HDR) shot.
For the easy understanding, let’s say it produced 3 RAW files.
4. How to post-process to create an HDR image?
Now let’s learn how to produce HDR images.
For the explanation, I’m taking the Adobe Lightroom Software as an example. Most photo editing software applications have the HDR option.
After you upload all the source files, select all those files and click the menu option: Photo Photo Merge HDR Merge.
This will bring up a window where it’ll start the merging process. Until it completes, let’s understand a few concepts.
The final HDR image is produced by taking the best-exposed portions from each of the source images. Thus, the highlights and shadows are both covered well in the final image making the dynamic range to be high. Therefore, to be able to use the best portions from each source image, they all must carry the same field of view.
As I mentioned before, if there’re any moving objects in the field of view, it’ll create a ghosting effect. Ghosting means, the blurry and multiple images of the same object will appear in the final image.
Consider a situation that a person is walking across the field when you take the shots. He’ll appear in different locations in the field across the different source files. Thus, the final image will end up showing a blurry/multiple images of him/her.
Luckily, photo editing applications provide an option called “Deghosting”. It’ll attempt to reduce/smoothen such a ghosting effect. They also provide different levels of de-ghosting – such as high, medium, low, etc. In Lightroom, in the HDR merge screen, there’s a slider for choosing this level as shown in the picture below.
You can try each value and check the preview. You can choose the optimal setting which results in a better output. There’s another option “Show Deghosting Overlay”. If you select it, it’ll highlight the ghosting areas in the image with a red colour overlay. This is seen in the picture above and below.
This indicates how much de-ghosting will be done (based on the slider selection). Based on that, you can choose the optimal level in the slider. Check how the aesthetics and quality of the final picture is benefited or affected by the de-ghosting level selected and whichever setting looks comfortable, you can choose the same.
“Auto Align” is another option in the HDR merge. This helps align the source images if the frames are (even slightly) different. If the field of view remained the same, the alignment wouldn’t be a big problem. Still choosing this “Auto Align” option doesn’t affect anything. It’ll help automatic adjustments so you can leave it turned on almost always.
Alright, the merging process must have been completed now. See the preview image to confirm it looks good.
If the de-ghosting and auto adjustments look good to you, click “Merge”. Lightroom will take some time to perform the merge.
Then it’ll create a final image file (typically xxx-HDR.dng file). This DNG file is a “Digital Negative” file, which is a RAW file. Thus, it carries all advantages of a RAW file (over JPEG). The important benefit is, even if the source files are JPEG, the HDR file will still be created as a DNG file.
After the HDR file is created, you can still post-process it further by making various changes as you would do to a usual RAW file – color tone, other effects, etc.
When you view all your photos (catalogs) in Lightroom in the “Square Grid” view. On each image, file Lightroom shows a caption about the type of the file – CR2, JPG, DNG, like that. Additionally, for the HDR (final) image it also shows the caption “HDR”. Both these are pointed out in the image below. This is handy when you glance through all your images in Grid view to identify which of them are HDR images vs normal images.
5. Example HDR images
Let’s see some example HDR images I’ve captured and created. I have set up the camera for 3 bracketed shots and +/- 2EV to take these shots.
The following images are the three bracketed shots captured by the camera as I clicked once.
This is the normal exposure (meter level 0). f/11, 1/200, ISO-100 were the settings. These were the settings I set up before taking the (HDR) shot.
This is the underexposed shot (meter level -2). f/11, 1/800, ISO-100 were the settings camera chose to capture this shot. As I mentioned before, the camera chooses to change the shutter speed. Since this exposure was set as -2, the number of F-stops in reducing the exposure must be 2. The levels for shutter speed are 1/200, 1/400, and 1/800, going from slow to fast speed. So, it’s going from more light to less light to underexpose. Hence camera chose 1/800 which is 2 steps down from the default 1/200 for the shot.
This is the overexposed shot (meter level +2). f/11, 1/50, ISO-100 were the settings camera chose to capture this shot. As explained above, since 1/200, 1/100, and 1/50 are the F-stops of shutter speed, going from fast to slow (i.e., less light to more light), the camera chose to capture it as 1/50 for the 2 steps up.
This was the final HDR image I created after post-processing. Of course, the tone is a bit heavy but for this scene, I preferred this tone. The rainbow is also projected prominently very well, as compared to the normal exposure shot.
These are many more examples of HDR images I’ve created.
6. Important Do’s and Don’t’s
Professional photographers sometimes avoid HDR images for the reasons that those images are over post-processed, oversaturated, and over toned. Let’s understand some important Do’s and Don’t’s of creating HDR images.
These are the situations when you can think of creating HDR image instead of the usual image.
- Landscapes: When the sunlight is brighter than the subject (or) when there are a lot of colour elements in the frame, HDR shots are beneficial. They bring out better tones and colours.
- Low-light situations: In low-light situations on the field, HDR images will help highlight and project the scene better. This will brighten the shot. However, default (normal exposure) must be captured with ‘not-so-slow’ shutter speed, else HDR won’t help.
- The subject under shadow but the background is bright: In this situation, normal shots will make foreground dark or background too bright, losing details of one of these two elements. HDR shot can help here exactly.
There’s no free lunch in the world. HDR shot isn’t a universal hammer for all the nails. There’re situations when HDR shot can’t and shouldn’t be used, else it’ll ruin the image.
- Movement in the scene: As I mentioned before, if there’s any movement in the scene then the HDR shot won’t show up well due to ghosting.
- Long exposure situations: During long exposure situations like Sunrise or Sunset, HDR shot will become ‘double-edged-sword’. If the shutter speed is good enough (something more than 1/100, as an indicative example) then HDR shot will bring out your best “Sunset/Sunrise” shot ever. Otherwise, if the shutter speed is already low, then taking bracketed shots will be challenging and hence HDR shot will be tricky. Tripod is something that can help but despite using a tripod if there’ll be any movements in the frame due to low shutter speeds across bracketed shots, it’ll ruin the shot.
- Excess Colour Processing: HDR shots are known to enhance the colours of objects in the shot. If your situation demands real colours to be captured “as they’re”, it’s advisable to avoid HDR shots.
Hope the article explained well about how to take HDR shots, how to post-process the shots to create a final HDR image, and in what situations HDR shots will help vs not.
Happy Photographing !!
Author “SathyaSri” in an avid photographer. Check out his profile in WPC at https://www.worldphotographersclub.com/sathyasri/photos. Follow his handle https://www.instagram.com/craving.visuals/ to see his shots.