WHAT IS HDR PHOTOGRAPHY?

I have received a lot of questions lately from people wanting to know what HDR photography is and why it looks so much different than a normal photograph. I figured I would write a blog post about it and explain from my point of view why HDR is so amazing and what makes an image an HDR image.

HDR stands for “High Dynamic Range.” An HDR image combines all the available light in a scene into one image. You may have noticed that when you take a picture on vacation (I used to do this all the time), it never quite does justice to your memory of that scene. I specifically remember driving to Table Rock Lake in Missouri back when I was knee high to a grass hopper. We drove up to a place on the side of the road marked “Photo Opportunity” and from that point you could see for literally miles. The lake looked as if it went on forever. The sky was bright blue with dramatic clouds. The scenery went on forever. I grabbed my camera and snapped off a picture before driving to our destination.

I remember getting my film developed at Wal-Mart and eagerly anticipating that one picture. I could still remember it so vividly in my head. I grabbed my pouch of images from the desk and opened it with great anticipation, but when my eyes finally found the image a frown came across my face. “That’s not what it looked like at all,” I muttered to myself. My camera could not capture the full dynamic range of light in that scene. It was just too great a spectrum: The intense light coming from the sun, the reflection off the water combined with the deep blues and greens of the lake. The bright greens of the trees along with the dark shadows cast by them.

HDR processing fixes this problem! Now I can take an image and capture the exact emotions and mood of the scene on that very day! I can bring in the dramatic tones of the clouds and the streaks they make across the sky, as well as the captivating textures of the water crashing against the shore line, and at the same time get every detail in the greenery. But how is this possible you might ask? Is there some new camera out on the market that nobody knows about yet? Hardly! HDR processing starts with the same camera I use to shoot weddings, families, seniors, etc. The difference is the set up of the shot and the post processing of the image after-wards.

An HDR image starts with taking multiple shots of the same scene. It is ideal (and required in some cases) that you use a tripod for this step. Any movement of the camera can cause more work in post or ruin the image completely in low light situations. In most cases, three images of the scene are enough to capture the full range of light in a scene. However is some cases it may require five, or seven even. After composing the scene, simply take three images: one at the “correct” exposure for that scene, one 2 stops under-exposed, and one 2 stop over-exposed. So -2, 0, +2. In rare instances, like shooting into the sun; -2, -1, 0, +1, +2 and so on. Some people even take 9 exposures but I’m not sure my computer would like that! Your images will look something like this:

SO WHAT’S WRONG WITH THOSE THREE IMAGES

Glad you asked! If we start with the first one (underexposed) you will notice that the detail is primarily in the sky behind the aircraft (C-1 Trader) as well as the front of the aircraft. In photography you don’t want to lose any detail in the image. So if parts of an image are too dark, that part of the image turns pure black, which is BAD! We call it “blowing your shadows,” or “blowing your highlights” if you are referring to pure white being present. Pure black or white means parts of the subject are lost. In the under exposed image the shadows are consumed by pure black inside the engine and around the letters on the side of the plane. Since it is pure black, there is nothing to see!

In the middle image, the properly exposed image, the plane is exposed for the most part. There are some blown highlights at the top of the plane due to it’s finish and the harsh sun light from that day. You notice a lot more detail in the plane itself, but there’s one thing missing. One thing that will make you think, “Well that’s not what it looked like.” The sky! Because there was such a big difference between the light falling on the plane and the bright sky, the sky has been nearly lost in this image. The is barely any detail in the clouds at all. But the clouds were so beautiful that day, I guess you just had to be there .

The third image is 2 stops overexposed. This means two steps brighter than what the camera thinks the image should be. I should also note that when shooting a scene for HDR, you cannot be using your camera in an automatic mode! Stay away from the green box on your camera! When you take a picture in automatic you aren’t really taking a picture, Canon is, or Nikon is! You are letting your camera decide how to create the look of the image. You let the camera decide your depth of field, your sensitivity to light, your white balance, your shutter speed, your metering, etc. You are just the middle man who holds the camera for them! If you really want to become a creative photographer you must learn to work in the creative modes. And HDR is done best in “Aperture Value” mode, or “Aperture Priority.” This means you set aperture (depth of field) to one place and that setting never changes during your three images. In manual, shutter priority, or automatic the depth of field would change in every frame and that would mess everything up. But I digress: You will see in this third image that the sky is completely lost. No detail at all, just pure white. In fact, the majority of the image is lost. The plane almost seamlessly blends into the sky behind it, as well as the ground beneath it. But there is a few parts of the image that I captured brilliantly. Look at the incredible detail in of the propellars and mainly the details of the engine! You can see everything in there! There is also great detail in the tires of the C-1 and the inner workings around the landing gears. This image would be great if all I remembered was the engine.

But I remember the beautiful, dramatic sky with slightly present storm clouds appearing. I remember the shiny finish of the C-1 Trader and beautiful curves of the planes body. I remember seeing the city of San Diego behind the aircraft carrier and how the ocean was just to the right of us. I remember there were dummy’s dressed up in flight suits sitting in the cockpits of every plane, and how that kind of bugged me sometimes. It seemed to ruin a couple of shots I wanted to get.

After reading Trey Ratcliffs book on HDR photography, I completely agree that we remember scenes in a sort of fantasy-like way. Some things are slightly exaggerated; colors, saturation, details, etc. The further away from the present the event becomes, the more captivating that fleeting moment becomes. So what if you want to capture every part of that image? The details of the C-1 Traders motor and it’s inner workings, the slightly intrusive dummy in the cockpit, the brilliant finish of the aircraft and it’s curves, the incredible drama of the clouds in the sky as well as the Pacific Ocean to the west of the scene…that’s where HDR processing can bring to us an image like this:

SO HOW DO YOU COMBINE THE MULTIPLE EXPOSURES TO GET THESE RESULTS

HDR is a ground breaking process. HDR software crunches your multiple images using advanced algorithms and scans the photos on a pixel to pixel basis in an attempt to find the best light sources from each image. There are a number of programs out there that you can use, but the most widely used (and best in my opinion) is Photomatix. I believe it costs somewhere around $120 for the bundle for Lightroom or Aperture.

Now I find that Photomatix usually give me a “rough draft” to start with. The real magic happens in photoshop. Photomatix is not a perfect program and runs into issues with things like movement in the scene. If you are shooting a beach with waves or a flag blowing in the wind, the software will fail at the part of the image and produce what’s called “ghosting.” It also causes a side effect called “haloing” around high contrast areas. Halos can be very hard to fix sometimes but it can be done. Once I have the image in photoshop I bring in all three images from the camera, the “RAW” files. If Photomatix failed anywhere in the image, I can mask in the parts of the image I want to bring back or remove. I would say that this part of the HDR process takes the most skill. There are a lot of things in photoshop that require a lot of training and additional hours to become used to. If this overview of HDR receives feedback from my readers I will elaborate on the steps in photoshop at that point.

The last step once I work my magic in photoshop is to run it through a filter. The filters in photoshop are nice, but they just aren’t enough sometimes. My favorite plug in for HDR filters is by Topaz Labs. I would suggest buying the photoshop bundle package for a little more. It comes with a whole suit of filters to help make your image stand out. It also includes a noise reduction filter which is essential for HDR. The HDR process can bring a lot of digital noise into a picture, even taken at ISO 50.

I hope this brief overview has shed some light on what HDR photography is. Since diving into it, I can never look at a landscape image the same way if it’s not HDR. A normal photograph just doesn’t do it justice in almost all cases. There are always exceptions though. Like I said, depending on the feedback I get from this I will be more than happy to dive deeper into the details of my workflow. If you have any questions, leave a comment below. If you follow me there are a number of ways to contact me besides here, via facebook or twitter. Thanks for digging my work and God bless!