For Realistic Images and Maximum Tone Control
In this article, I'm going to walk you through what you need to know to shoot bracketed exposures for HDR properly and process them using the Merge to HDR function in Lightroom. Follow along with me if you like the idea of getting maximum detail in your images, having full tonal control of bright highlights, and having realistic looking finished image that sings.
What is HDR?
HDR stands for high dynamic range. Put simply, that means the range of contrast in a given scene is high. So high in fact that your camera cannot render detail in both the highlight and shadow areas. You're forced to make a choice of how to expose and where you keep detail unless you do some special techniques which have also become known as HDR. It gets a bit confusing because the term is really about the contrast range of your scene, but it's become synonymous with a particular process as well.
HDR has been around for a long time, and I don't just mean since Trey Ratcliff made it popular a few years ago. No, I mean since the days of Ansel Adams, long before digital photography was even an idea. It's gone through a few phases and I think HDR has finally come around to where most people want a more realistic look once again (thank heavens!). That is as opposed to the heavily saturated, halo in the sky, a funky looking style that was all the rage for a while. Okay, I'll admit it, I'm guilty of that too, but I've come to my senses at last.
I've talked about the importance of actually having shadows in your images in the past in this article: 5 Tips for Using Shadows to Create Dramatic Images. When you eliminate all shadows completely and pull them down to mid-tones, then do the same with the highlights – you're left with a mushy mess with no contrast. To me, that is NOT the point of doing HDR.
Here is an example of what I suggest NOT to do:
The other end of the spectrum is more a natural looking result. This is where the process is used only for tone control to pull detail out of both ends of the histogram. Here is an example of a more natural and realistic looking HDR. We'll use this as our example for the rest of the article.
One important thing to remember here is (write this down, save it, tweet it, and memorize it):
Doing HDR will not save a badly composed, poorly lit or boring image!
NOTE: However, if you do like the highly stylized, saturated HDR look then I say go for it. Who cares what I or anyone else think if you are happy with your images! But just remember to keep the basic elements of great photography in mind as well: good lighting, composition and a centre of interest.
Camera settings for shooting HDR
How far apart to bracket your shots is up for debate, but there are a few things most photographers agree on.
- Shoot RAW format if possible.
- Adjust ONLY the shutter speed when doing HDR brackets. If you bracket using aperture you'll have a mess when they merge due to the changing depth of field.
- Use the lowest ISO possible (ideally 100 or 200). The process introduces noise so keeping the ISO low helps.
- Use a tripod whenever possible. You need to make sure the bracketed images will align perfectly in processing.
- Use focus lock, back-button focus or manual focus when shooting. You don't want the focus to shift between brackets.
I personally also recommend the following:
- Shoot in manual mode when possible (when you're using a tripod). You can also use Auto Exposure Bracketing but if your camera doesn't bracket 2-stops apart, or do at least 5 images I'd suggest manual so you get more range.
- Use your histogram to review the exposures.
- Turn on highlight warnings (they will blink when you review the images on the camera).
- Use AEB (auto exposure bracketing) when shooting without a tripod, set to 2 stops apart (if your camera only goes one stop apart maximum, just shoot more frames like 7 or 9).
Shooting the bracketed images
I highly recommend bracketing shots 2-stops apart – RAW files carry data at least 2 stops either way (under and overexposed) so if you shoot 1-stop apart you are getting a LOT of overlap. More than you need in my opinion, and you can't cover the same range of exposures in say 5 shots. One stop apart gets you: -2, -1, 0, +1, +2 for a 4-stop range. Two stops apart gets you: -4, -2, 0, +2, +4 for an 8-stop range. See the difference?
Shoot a series of images from the darkest (no highlights are off the chart and the histogram is mostly to the left) to the lightest (no shadows off the chart and the histogram is mostly to the right) changing the shutter speed in increments of 2 stops apart. Here is a set of five images I shot to get details at both ends of the full range of this scene. Shooting from an indoor location and including windows is one of the highest contrast scenarios you could encounter. It works perfectly for this example.
What you want to take note of in the five images above is that the darkest one has NO clipped highlight areas, notice the windows and spot on the floor. Conversely, the brightest image has no clipped shadows (not touching the left of the histogram). It will have a lot of blinkies and clipped highlights – that's what you want! See how much detail there is in the black wood stove in that image.
NOTE: Remember that ONE STOP is double the amount of light and 2 stops is 2×2 or 4x more light. So if you are in Manual Mode make sure you are adjusting far enough in between brackets and keeping the increments consistent, Most cameras are set to adjust shutter speed in ⅓ stop increments so if that is true of yours, you need six clicks of the dial to go 2-stops.
Tip: Take a photo of your hand in front of the lens after each series so the beginning and end of each series are easy to spot later in Lightroom.
Processing your HDR images in Lightroom
Once you're back to home base import your bracketed images into Lightroom. I use the color flags in the Library module to mark all my bracketed shots so I can easily pick them out later for processing. You can see I've tagged them all with red here. Find a method that works for you, it doesn't have to be color flags.
Select your brackets and merge to HDR
Next select all the images in your bracketed set, in this case, I shot five. Make sure you get them all and don't get any extras. It looks really odd, or Lightroom will give you an error message if you select one that isn't the same and it can't merge them. With all the bracketed images highlighted, right-click and choose: Photo Merge > HDR.
You will get a popup dialog box that looks like this. If you shot a scene where nothing was moving, don't worry about using the deghosting options. Check off the “Auto Align” one. Even if you shot using a tripod things can shift so it doesn't hurt to have Lightroom check that for you. I usually leave the “Auto Tone” option unchecked, it most often doesn't do what I want with the image. But you can try it, and if you don't like it just hit Reset once the image is opened in LR.
Click Merge and Lightroom will do its thing combining your bracketed images. It may take a while depending on how many shots you took, and the speed and processing power of your computer. (Another good reason for shooting 2 stops apart, I'd have needed seven images instead of four to cover the same scene.)
Finishing it up in Lightroom Develop module
You're not done yet! This is where the magic just begins. What Lightroom does with your bracketed images is combines them into one 32-bit DNG file, which it automatically imports for you (if it doesn't you may need to check your LR preferences). I won't get into the math but just know that it's like a “super-mega file” that can hold all the colors and details from all the other images combined. You just have to massage it a bit to get it to sing!
This is how the image shows up in LR before any extra processing. Doesn't look any more special than one of the originals right? But look what you can pull out of it when you know how.
See how there are now details in both the darkest areas in the shadows, like around the stove, and in the brightest ones like the windows and spot of light on the floor. BUT also notice that there are still shadows and highlights. I've processed it to maintain a full range from pure black to pure white and even bumped the contrast a bit using the Curves panel. Here are the global settings I applied.
Don't forget to do local adjustments too
But I still haven't pulled out maximum detail from this file yet. To do that I applied a few local adjustments using the Adjustment Brush. The windows had the highlights pulled down, the stove had a slight exposure increase and shadow lift. In the doorway itself, I did an exposure decrease and slight highlight decrease. The door good a clarity bump to bring out all the peeling paint.
This is bordering on too much processing for me and I would probably back off the local adjustments in the windows a bit more a more pleasing look to my eyes.
Compare the result to a single raw file
Just for the heck of it, I decided to see if I could pull out the same amount of detail from just one single raw file. These are from the Canon 5D Mark III so it's decent but an older model now. I may have more luck with a raw file from my newer, but smaller sensor, Fuji mirrorless X-T1 camera.
For comparison sake here is one raw file which I processed the one below from.
This is what I got from one raw file:
At first glance, it's not bad. But look closely at the spot on the floor and the windows. They're sort of turned into grey blobs with no detail. Compare the image above to the final version from the HDR merge (I pulled back on the local adjustments a bit).
If you must know, these are the settings I used on the single raw file. No local adjustments were applied.
Take a closer look at the shadows
Anytime you pull an image to its limits you run the risk of introducing noise or getting artifacts. When we view these two images at 100% (1:1 in Lightroom) you can see how much noise there is in the single raw file version. Click on the images to open larger versions in a new tab.
Notice the door looks relatively the same, but the detail and noise in the shadows is much better in the HDR image. Do this comparison on some of your brackets shots and see how your camera performs when you pull one image to the limits. This is the ultimate test of the range and capability of the camera (assuming a good exposure, to begin with).
Here is another set of bracketed images. Once again shooting from inside with a window in the room showing.This one required only four images (shot 2 stops apart) to get the full range.
Here is the final version after doing Merge to HDR in Lightroom and a few local adjustments.
I added a slight split tone to warm up the shadows and give it a gentle antique look and feel. See how much detail has been retained in all areas, yet it doesn't look unnatural.
Once again I processed a single raw file to see how it would come out. Notice there is a lot of detail in the shadows but the windows are a big blog of epic failure in my mind.
I'd rather leave the windows bright and blown out (maybe even add a blur to make them glow) than to have them go all muddy like the image above. How about a graduated filter added in the upper left corner that pulls the Clarity way down, exposure up, and adds a yellow tint? Like this:
I MUCH prefer this to the one above! Can't you just feel the sun here? Keep in mind that you do not always need to have detail everywhere. You get to decide based on the feel you want for the image.
Finally, compare to this version which I did about four years ago using Photomatix. That was a transition phase for me. Lightroom hadn't yet added the Merge to HDR function and Photomatix was still the best choice on the market for doing HDR.
It's not bad or too over the top and there are things about each finished version that I like.
Bottom line and your turn
The bottom line here is that I encourage you to experiment and play around. By pushing things to the edges of what you feel is even acceptable you may just find something you like. So for you, find the method that works for you and style you like and go with that.
Please post any questions in the comments section below and I'd love to see your images done with LR Merge to HDR.