High Dynamic Range (HDR) Tutorial – How to make stunning HDR images with your camera and Photomatix
What is a HDR Image?
A high dynamic range image is a digital photograph that is displays much more tonal range that a traditional photo can. It captures detail in the extreme shadows and highlights that would normally be shown as pure black or pure white. In essence, it creates an image that is similar to what our natural vision and brain are capable of interpreting.
This tutorial assumes that you have the following essentials:
A Tripod.
A Digital Camera with bracketing feature or at least a manual exposure function
A basic understanding of how your camera works and basic photographic ideas such as shutter speeds and f-stops and how they effect exposure.
Photomatix by HDRSoft (or similar).
The Process:
Begin by setting up your tripod and camera. Scenes that traditionally translate into amazing HDR images are those that would be difficult to photograph using standard methods, such as sunsets, brightly lit landscapes, etc etc. Note that moving objects can be your worse enemy when creating HDR photos. If you are shooting outdoors and it is windy or even a little breezy, you may get some odd looking results.
Set your camera to shoot in its RAW format if available. (Nikon NEF, Canon CR2) or to your hightest JPEG settings possible. RAW formatted images are preferred as they contain the highest amount of information possible from your camera’s sensor.
Set your camera to use it’s bracketing function. You are going to want to take at least 5 images at .7EV to 1EV increments apart. For HDR, I typically take 7 shots in 1EV increments. In the example photos below, my camera metered the scene at 1/40 sec @ f3.5 at ISO 400. (click for larger version). If your camera does not have a bracketing program, you can still accomplish the exact same thing using your manual exposure settings. It is just a little more time consuming and tedious. Check out your camera’s manual on how to shoot in manual modes.
It is best to put your camera in continuous shooting mode so that you can capture the necessary frames as quickly as possible and with as little camera shake as possible.
If depth of field is not an issue in your final image, place your camera in is auto or “program” shooting mode. this will likely give you the fastest shutter speeds possible, therefore reducing blur. If depth of field IS an issue, you should place your camera in its “A” or aperture priority shooting mode while bracketing. That way your f-stop will remain constant, while the camera varies the shutter speeds.
Shoot away! You should get 7 images (or however many you chose to bracket) like the ones below, varying from dark to light, light to dark, or some other order depending on your camera and settings.
Download the images to your computer. When working with HDR, I tend to try to keep everything in one working folder. It makes my life easier since we are dealing with multiple files.
Fire up Photomatix
Once open,
1. Click HDR
2. Click GENERATE
3. Click BROWSE
4. Navigate to the photos you just took
5. Leave settings at their default and click OK
7. After some time, you will be shown your converted raw HDR Image
Pretty ugly. Right? The actual HDR image that you will be shown is usually quite unflattering. That is because there is SO much data there (we’re talking about a 32 bit image here), your monitor is completely incapable of displaying all of it.
This shortcoming is what leads us into the key part of creating an attractive HDR image. It’s called Tone Mapping.
The easiest way to think of tone mapping is that you are condensing (remapping) the tones in a gigantic histogram, (a histogram that contains tones that are way out of the range and capability of your monitor) into a smaller space that your monitor, color space, and computer are capable of showing.
Look at this crude demonstration. Think of this as the histogram for a newly converted HDR image out of Photomatix.
Tones that fall in the HDR range of the histogram are tones that are inpossible to display on your monitor and therefore appear as blown out or completely stopped up spots in an image. When you tonemap your HDR image, it takes those values that are out of range, and it remaps them into a new histogram that your computer is capable of displaying. Think of it as photoshop’s “levels” tool on steroids.
To tonemap your image using Photomatix:
Go to the HDR menu and click Tone Mapping.
You will be presented with a filter looking dialog box with several options and a preview that approximates what your tonemapped image will look like. I say approximates because apparently, tonemapping is such a mathmetically intensive procedure, that there is no way, (as of yet) to truely and accuratly preview the results of tone mapping. Often times, your preview will look way better than your final results. Sad but true.
The best way to learn this part of the application is to play around with the settings. If you think you like what you see, and click OK, and then decide you hate it, you can always use the “Undo Tone Mapping” in the HDR menu.
Successfully tone mapping your image will shrink all of those hidden tones and place them into a more understandable histogram. Remember that histogram example? Here is the same image, after tone mapping.
A general Starting point for tone mapping in Photomatix might be:
Strength 70-100
Saturation 40-50
Light Smoothing High or Very High (interestingly, the lower the setting here, the more dramatic the HDR effect appears)
Luminosity 8-10
The rest is up to you and your preferences.
Once you have a tone mapped HDR image that you really like, your not done! Tone mapping is just the beginning of the story. Save your image as a TIF (jpeg is a lousy format to save in for this type of work) and open in Photoshop or your favorite image editor and do your normal tweaks… curves, levels, etc etc.
Best of luck!
Original image out of camera:
End Result after HDR conversion and Tone Mapping:
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