Everyone knows I love doing HDR photography, so several people have asked me write an article on it. Actually, there are numerous books, so rather than try to do this as a single article, this will be a multipart article. First I’ll explain what HDR is, why to use it, and the basics of shooting for HDR. In the next articles I’ll discuss various programs and methods for creating HDR images, and how to apply the finishing touches in Photoshop.
What is HDR
HDR stands for High Dynamic Range Photography. Our eyes are capable of seeing more than 20 stops of dynamic range. That means we see into the shadows and still can see detail in the highlights. On the other hand, our cameras can see only 10 or 12 stops of dynamic range. We can improve that somewhat with post processing, but still detail will either be lacking in the shadows, or highlights or if the contrast is extreme, both.
In HDR photography we “bracket” by taking several images over a range of exposure from underexposed to record highlight detail to normal and then to overexposed to record shadow detail. We use software to combine and process all of these images into one image that has a greater dynamic range than is possible straight from the camera. There are several software options for processing HDR and each has its own advantages, disadvantages and “look”.
Figure 1A normal exposure has dark shadows and blown out highlights in the window
Figure 2 The HDR image has good detail in both the shadows and the window.
In addition to HDR, Rick Sammon talks about “EDR” or extended dynamic range. This is processing a single image to lighten the shadows and lower the brightness of the highlights. It is an improvement over the straight image, but it still can’t handle the extremes that HDR can.
Figure 3 An “EDR”. This is a single image with the shadows lightened as far as possible and highlights decreased as much as possible in Lightroom. It’s better than a normal image, but still doesn’t have the range of a true HDR image.
Why shoot HDR
HDR is absolutely the best way to maintain detail in extreme contrast. Typical examples are shooting inside a church and trying to maintain detail inside and in the stained glass windows, shooting a subject in heavy shade when the bright sky is also visible and trying to maintain detail in the subject and also in the sky. I often shoot HDR when the range of contrast doesn’t demand it, but I like the “look” of HDR which seems to intensify and exaggerate textures, and make colors pop.
Figure 4 No single exposure could capture the dark interior, bright ceiling lights and very bright exterior in the windows. Bill Mueller convinced me to try my first ever HDR on this 2010 field trip. He had no idea of the monster he was about to create.
Figure 5 Contrast wasn’t too bad this day and this single image has pretty good detail throughout.
Figure 6 This is the HDR version. While it wasn’t necessary to control contrast, I prefer it for the overall feel and snap particularly the sky. You may prefer the original.
Figure 7 HDR wasn’t necessary for the contrast range here.
Figure 8 But again, I prefer the texture and pop of the HDR.
What to shoot in HDR
So if you ask “what subjects can I shoot in HDR?” I, being the HDR fanatic that I am would answer almost anything you want to. Typically, most people think of hard subjects like machinery and old buildings, but give it a try with flowers and other soft subjects. The two main subjects that don’t work well are people and moving subjects. Small areas of movement like a fluttering flag cause ghosting that can usually be corrected by software. Large movements like people walking, cars and bikes moving, birds in flight won’t work. And HDR is rarely good for people photography; nobody wants all of the detail and texture in their skin enhanced.
Figure 9 What can we shoot – grungy old buildings
Figure 10 Or we can shoot beautiful buildings
Figure 11We can shoot hard industrial equipment
Figure 12 Or the softness of a water lily in rain.
Figure 13We can shoot dark stormy skies
Figure 14 Or postcard blue skies
When do we shoot HDR?
The short answer is anytime. Night, sunset, sunrise, midday, good skies, bad skies, high contrast light, dappled uneven light, even low contrast all work. I was taught not to shoot between 10AM and 2PM, because the light was too contrasty with unpleasant shadows. Now with HDR, we can even work around that.
Figure 15 Nighttime
Figure 16 Sunrise
Figure 17 Midday bright sun
Figure 18 Sunset
Figure 19 How about HDR for people?
Figure 20 Probably not if you ever want to photograph them again. HDR is not flattering to skin.
We can even do HDR Panoramas
The trick here is to make your brackets in manual mode. Once you have your brackets shift over leaving about 20% overlap, then repeat for as many sequences as it takes to cover your panorama area. Then you must process each of the HDR sequences exactly the same way, so the images will blend well when merged into a panorama.
Figure 21 5 HDR images were stitched to create this panorama
How to Bracket
There are a couple of ways to bracket. The most important thing is to keep the aperture constant and bracket by varying time. If the aperture changes, it will slightly alter the look of each image and they will not line up properly when combining the images for HDR. Shoot in either aperture priority or manual mode. Also focus must stay constant. Either use manual focus, or set your camera for back button focus, focus once and don’t change it for any of the shots in the bracket series.
I prefer to shoot all of my brackets on a tripod. Some of the software programs will align images that are slightly off from being hand held. But unless you are in very bright light, you will run into issues with slow shutter speed and camera movement. Also I find it best to turn off image stabilization (IS, VR, OS). And shoot at the lowest possible ISO. HDR photography often seems to work best at small apertures, so you will sometimes have to increase ISO. Just be aware that HDR tends to increase noise.
Whichever mode you use, take a meter reading and shoot exposures below that, at the meter reading and above the meter reading. You can manually adjust your exposures by changing your shutter speed. You decrease exposure by setting faster shutter speed, and increase exposure with slower shutter speed. In a dark room, it’s very common for the slow exposures to be 30 sec or longer.
Most current cameras can be set to bracket automatically. On my Canon 5D Mark III and 7D Mark II I can set the camera to shoot 2, 3, 5, 7 or 9 brackets up to 3 stops apart. Nikon I believe only lets you set up to 1 stop apart. On most cameras once you set the bracketing, set the drive to high speed and press and hold the shutter and the camera will shoot the set number of brackets and stop. On my Canon I can set the drive to 2 sec self timer, press the shutter and after 2 seconds it will shoot the whole sequence. That way I don’t need a cable release, but I don’t get vibration from pressing the shutter.
Every camera is different, so read the manual to find out how to set bracketing and practice it before going out to shoot.
How Much to Bracket
Look at your bracketed images and make sure the darkest image has good detail in the brightest highlights that are important and the brightest image has good detail in the darkest shadows. If they don’t, then either increase the number of brackets, the stops between brackets or both.
I usually bracket in 2 stop intervals. In average or low contrast light such as cloudy days 3 brackets is usually enough. Bright contrasty sunny days may require 5 brackets. And situations with vary dark areas and extreme bright may require 7 or even 9 brackets. This would typically be shooting inside a dimly lit building (or car) where you also can see out windows in bright daylight.
Here is a less technical way of looking at it. It’s always better to have more brackets than you need, than not have enough. You can delete that solid black image and the solid white image in a second. But what if you traveled 700 miles, paid for a workshop or rented a location and come home to process and realize you don’t have enough brackets to cover the shadows and highlights? When will you ever be there again, and how much would it cost to go back and reshoot? If you look at it that way a few extra brackets are cheap insurance.
Here is a 5 shot bracket and the resulting image. Notice the detail in shadows and highlights at each end.
Figure 22 -4 Stops to get detail in the clouds
Figure 23 -2 stops
Figure 24 normal exposure
Figure 25 +2 sops
Figure 26 +4 stops for detail in the shadow under the dash
Figure 27 the HDR assembled from 5 brackets.
Below you can see what happens when you don’t have enough brackets. The software is forced to try to bring out detail where very little exists. In dark areas this results in poor detail with lots of noise.
Figure 28 The same image processed using only the three middle exposures. Notice the noise and loss of detail under the dash.
A Little Known Secret
Everyone assumes I shoot everything in HDR, and for the most part they’re right. I do shoot HDR brackets for almost every inanimate subject. The secret is I don’t always use them to create an HDR image. If I see that I can get all of the detail I want in a single image, I’ll process the one image in the sequence that has the best exposure and the feel I’m after. The nice part is that even if I wind up not doing an HDR, I have a range of exposures from which to choose.
In the next few articles I’ll discuss how to process an HDR image in NIK HDR Efex II, Lightroom, Photoshop, and Photomatix. And in the last article I’ll explain how to finish and fine-tune the image in Photoshop.
I have converted all of my old articles into web format and put them on my website under the “Articles” heading. I’ll be adding this and all future articles so that my followers (both of them) can find everything in one location.
