Workflow Tips For Creating Realistic HDR Images with Photomatix
by Eric Leslie
HDR is a very polarizing subject filled with very strong emotions. People seem to either hate it or love it. The haters tend to say things like, "I like HDR when it's done right" or "I like HDR when you can't tell it's HDR" with no real qualifications for what that really means. Unfortunately the term HDR seems inexorably linked to those images that are processed with a very grungy and cinematic feel to them. I like to think of HDR more broadly and include all images that have a greater dynamic range of light than the camera can capture in a single frame. I go as far as to include images that are shot with a GND filter.
I'm not normally thought of as a HDR photographer, but I use many of the same techniques HDR photographers use to achieve more "natural" or "realistic" results. In this post I'm going to go through my whole thought process for how I shot and processed one my favorite images, Date Night.
Creating the BracketsAfter finding this composition, I had to made decision about how I was going to take this shot. 3/4s of the time I will double process a single RAW file or take two exposures and manually blend them together with layer masks in Photoshop. Neither of those would have worked here for a couple reasons. Using your histogram, you can capture the entire dynamic range in two frames most of the time. This shot would have needed at least three because it was very dark throughout most of the scene, yet the sun was still very bright behind the oak trees. Blending with more than two shots is much more time consuming and I'm lazy. Not having a clean line to divide the two exposures makes the blend even more difficult. Back lit trees are about as hard as it gets and I'm just not good enough to make that blend look natural.
Running that all through my brain in a few cycles, I knew I would have to bracket this shot for an HDR. The traditional thing most people do is auto bracketing at least three shots from -2EV to +2EV. If your camera supports five shots, then having more intermediate shots helps. But I don't use auto-bracketing because I think it's the same thing as bringing a canon to a deer hunt. It's too broad lacking the precision I want. I use my histogram to shoot my brackets and that determines how many frames I get. Starting with the sky getting the fastest (darkest) exposure, I shoot until I get the highlights in the histogram all the way to right hand side without clipping. Most DSLRs have a clipping indicator which highlights the pixels that are either over exposed in the highlights or under exposed in the shadows. Once I get that exposure dialed in, I repeatedly shoot longer exposures 3-stops (1EV) apart until the shadows are exposed properly without clipping. This shot needed 6 frames.
Processing the BracketsLightroom 4 is my homebase and my first step for everything I do. After the RAW files are imported, the first thing I like to do when I know they are going to get merged together, is correct the color fringes and barrel distortion. This particular lens, the Nikkor 18-105mm, has a built in lens correction profile so it's as easy as checking a box to correct. Once the files leave Lightroom and return as a TIFF, I can't use the automatic lens correction.
There are many different choices today for creating the HDR, but what I keep coming back to is HDRsoft's Photomatix (Look for a special deal at the end). The exposure fusion mode is really amazing and that's what I'm going to walk you through here. Photomatix has an export plugin for Lightroom which allows me to set parameters in Photomatix like how to remove ghosting and if I want it to remove chromatic aberrations.
I like it to align the images by matching features just in case I bumped the tripod and I let it crop the the image for me if needed. I also let it automatically try to remove ghosting artifacts using high detection. This helps remove blurry leaves that might be blowing in the breeze. I let it detect and remove chromatic aberrations. Last, I have it re-import the final image back into Lightroom stacked on top of the other images in the bracket.
If this is your first time in Photomatix, it will default to the "Tone Mapping" option at the top of the Adjustment Panel. Click the radio button to switch it into "Exposure Fusion". Right off the bat the default settings don't look to far off for this shot. As I step through how I set each of these sliders, keep in mind that each photo is going to require different inputs that meet your taste. That said, I almost always take the Accentuation slider and nearly max it out. This really makes the photo pop. The rest of the sliders I adjust to balance out the Accentuation slider.
The Blending Point slider basically sets where in the bracket the center of the exposure should be. Most of the time this is on the left hand side of the shot, but in this case, the shot is very dark to begin with. So by sliding it to the right, I am allowing some of the detail right around the sun behind the oak trees to go away in favor of bring out the shadow detail through out the rest of the frame. Again, adjust this to suite your taste. If at this point the shadows are still too dark, you can manipulate the the Shadow slider to bring out more detail in just the shadows. In this shot, I moved it to 1.8 which added texture and drama to the clouds.
You can add sharpening here, but I rarely do. Same thing with color saturation. That said, since this shot was pretty dark, I did boost the Saturation two points to liven it up. The White and Black Clip sliders are really important and are often overlooked. If the colors flat and have a kind of dirty feel, you'll want to start with boosting the White Clip. If they're dull and shallow, adding Black will really add depth and saturation to the shot. What you are doing here is basically setting a custom white and black point like you would on the tone curve or levels adjustment.
Last is the Midtone slider which can help open up the exposure for the midtones and I really don't care for the results. It just looks terrible. So I will usually leave this slider alone. That's it! I do want to reemphasize to experiment with different slider combinations. I've found they are much easier to master and are much more predictable than the controls in the tone-mapping side of Photomatix. If you like what you see, click "Save and Re-import".
Finish in Lightroom and Bring it All TogetherNow we're on the 1 yard line and just need a few more tweaks. I always set a custom white balance and tint. I am a bit of a stickler for perfect color and there's really no quick way to get there in the camera. I wanted even more color than what I pushed out of the image from Photomatix, so I boosted the Vibrance slider. I also set the Clarity to +3 to give the light on the reeds more definition. There you have it!
It should be noted that most of the ease processing this HDR image came from the way I bracketed the shot. I am a firm believer that just taking three auto-bracketed shots is too generic. I know people auto bracket because it's easier, but is it really? I'm spending a little extra effort up front to save later in post processing. Not only is it easier for me, but I think the quality of the image is enhanced too. You didn't see me having to deal with halos around the trees and the settings in Photomatix were not hard to find. It all came together quickly and the results look great! No one has ever accused me of HDR malpractice because I consistently achieve results like this.
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What are some of the challenges you have faced shooting HDR?