- RAW editor such as Digital Photo Professional from Canon, Capture NX from Nikon, Camera RAW, Aperture, RawShooter, or Photoshop.
- HDR software, for this tutorial I use Photomatix.
Step 1: Source images
To create HDR images, we need more than one image file to combine in HDR 32 bit format. Usually, I use three images to generate the HDR image with a different exposure for each source images.
There are two main ways to create the source images needed for HDR. You can either use AEB (auto exposure bracketing), on your camera to take 3 images automatically or you can use single RAW image and use a RAW editor to produce 3 shots back at your computer.
This tutorial will show you how to create HDR image with auto exposure bracketing.
Auto Exposure Bracketing (AEB)
The main advantage with AEB is that you can get better source images with less noise. For example, a sunset. You would normally get really dark shadows and enhancing them later from 1 single RAW file would increase the noise.
With AEB you can take a completely seperate image for the shadows and one for the highlights to preseve the detail and keep the noise to a minimum. The disadvantge to this approach is that anything moving in the image will become blurred and repeated as it moves across the 3 images. To start with you will need a camera that has the AEB mode and a tripod. You will also need a tripod so that the 3 shots you take can be perfectly aligned later.
Go to the menu on your camera and set the AEB mode to -2 0 +2 stops. (I usually set this exposure). Compose your shot, and set the camera up as your normally would to take a picture. Now after you take a picture you will see the exposure compensation level drop down to -2. Take another picture and you will see it goes up to +2. You will notice the shutter speed or aperture changes too. This allows you to get the three shots for the shadows, a balanced image and for the highlights. You now have the 3 shots required to produce a HDR image.
Step 2: Generating a HDR image
Now, open your Photomatix software, and from the HDR menu select “Generate” then “browse” to open 3 source images and click “ok”.
Because you are using 3 source images with AEB, Photomatix will detect the exposure for each image. And now you need to choose the option for merging the source images to HDR. Let Photomatix aligns the images for you. Or you can check the “Attempt to reduce ghosting artifact”, this is to reduce the moving object in your images from ghosting effect.
Click ok and after a few minutes you will see your HDR image. It won’t look exactly right just yet. Some areas will be slightly over-exposed and it’ll look odd.
Step 3: Tone Mapping
Tone mapping is the magic part of the HDR image. It will convert your HDR image into something usable from 32 bit mode into 16 bit or 8 bit mode. Go to the HDR menu and select Tone Mapping. And select “Details Enhancer”, good technique in HDR tone mapping.
You will see how your photo looks more like a standard HDR image. The sky will be nicely exposed, as will the ground. The trick now is to adjust the settings to get a nice balanced image. You could be creative and go for something a little more fun if you feel like it. For the image in this guide I wanted something special and yet not too far from the real world. I’ll start with a quick run down of the various options.
Luminosity:
Adjusts the brightness of the shadows. Moving the slider to the right has the effect of boosting shadow details and brightening the image. Moving it to the left gives a more natural look to the tone mapped image. The optimal value depends on the image and the effect you want to achieve.
Strength:
Controls the strength of local contrast enhancements. A value of 100% gives the maximum increase in local contrast.
The optimal value depends on the image and the effect you want to achieve.
Color Saturation:
Controls the saturation of the RGB color channels. The greater the saturation, the more intense the color. The value affects each color channel equally.
White Clip - Black Clip:
From watching the way the histogram changes, the white clip adjusts the highlight contrast and the black clip adjusts the shadow contrast.
Micro-smoothing:
Basically this setting should be called “How arty do you want your shot?” At 0 you can get the cool arty style HDR images with all the detail in everything from walls to clouds you didn’t know where there.
However, if you want a nice simple blended exposure photo set it to 30. 95% of the image should be perfectly exposed as if you spent hours putting them together in Photoshop. This is a great new addition to Photomatix as it allows people to use the software as they see fit.
If they want a nice photo that is perfectly exposed then they can get that just as if they used ND Gradient filters on their lens. However, if like me they want something a bit more unique they can drop the micro-smoothing down and get something dramatic.
Light smoothing:
Never set this below 0 as you will get horrible results.
Microcontrast:
Controls the accentuation of local details. The default value (High) is the optimal value in most cases. However, this control may be useful in the case of a noisy image or when the accentuation of local details is not desirable (e.g. seams of a stitched pano in a uniform area may become visible when local details are too much enhanced).
As you can see, when you increase the strength, luminosity and clipping you increase the visible detail in the image. You can see more detail in the building and the clouds.
Three figures above, was setting with different value of Tone Mapping variables. Being creative with your own style! Choose the best tone mapping for your image. Remember, every image will can not be set with the same value.
Step 4: Final Touch
Now, after you create the HDR image with Tone Mapping, you can select the 16bit output to get the better detail on your image. And save it in TIFF image again.
The final touch is using Photoshop. You will need a little bit adjustment in Photoshop like adjust the level, curve, shadow/highlight, color balance (if needed), saturation (depend on your image) and sharpness tools to get more sharpness from HDR image.
When adjusting your image in Photoshop, remember to see your image histogram. Choose a good histogram from your image.
Issues
- Halo effects around buildings and people can occur too. I’ve read that this can be due to lowering the luminosity below 0.
- Don’t even think about ISO800 or 1600 unless you are desperate and have a great noise reduction technique. Use between ISO100 and 400 to reduce noise effect.
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