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Basic HDR Tutorial

UPDATE IN PROGRESS. Please stayed tuned!

Introduction

HDR is an acronym for high dynamic range, and makes for some pretty wild images. Your camera can only capture one lighting situation, even though our eyes can quickly compensate for too much or too little light when scanning a scene. So whereas our camera records a beautiful orange sunset with a pitch-black beach right in front of us, our eyes are able to catch detail in both the sunset and the beach. This is what HDR allows us to accomplish.

Let’s Get Right Down To It!

1. There are different ways to create an HDR, depending on whether or not you’ve got a single exposure or many. We’ll start by creating an HDR from a single exposure, since that’s probably how you’ll be starting out, too :) Download the original 5MBRAW file of a picture of an old Corvette, as shot from my camera, here. (If you have problems downloading this, try right-clicking, selecting Save As and ensuring that its extension is .nef instead of tif .) We’ll be running this through Photomatix to produce this image!

2. Download and install Photomatix from http://www.hdrsoft.com/download.html. They have a standalone application, which is what I use, as well as a Photoshop plug-in. The trial version is fully functional, although it watermarks each image that it creates. But that’s perfectly fine for this tutorial.

3. Open Photomatix, go to File->Open, and select my RAW file you’ve downloaded:

File->Open dialogue

You’ll see a ‘preview’ of the image on screen. Don’t worry if it appears too dark, this is not anything like what the final image will look like.

4. Go to Process->Tone Mapping:

Process->Tone Mapping window

This is where all the fun takes place! I’ve never played with the options under Tone Compressor, so everything you need to fiddle with is available under the Details Enhancertab.

5. The first options we’ll adjust are StrengthColor SaturationLight Smoothing and Luminosity. I want the Strength at 100% to really bring out the picture, and leave Color Saturation around 60%, as we don’t want the red of the Corvette to betoo strong. The lower you set Light Smoothing, the more exaggerated all the details of your picture will become. We don’t want this to look like something completely out of a comic book, so let’s set it to the second highest option. Luminositycontrols the tones in your image. Moving the slider to the left gives a more natural look, but for this example we want the opposite. Set it to the max! Your options should now look like this:

Details Enhancer

6. I usually like to max out the White Point, then adjust the Black Point until the histogram has a relatively good looking balance of black (toward the left side of the histogram) versus white (toward the right side of the histogram), but this image might look better if it’s a little on the dark side, so set these options as shown below:

Tone curve adjustments

You see the histogram? There’s an incline to the left, which means there’s more darks than whites in this image, thanks to the settings we chose for the White and Black points.

7. Select the Color tab. The picture looks too cold and blue with the Temperature set to 0, so we’ll set it to 4 for this example. Saturation Hightlights and Saturation Shadows control the strength of each respective level (for highlights and shadows, duh ;) ), neither of which would be very strong for this picture, so leave it at 0. Your settings should look like the following:

Color tab

8. Click the Micro tab. According to the manual, Micro-contrast “sets the level of accentuation of local details”. I have no idea what that means, but I like its results, so I always set it to the max at 10. Your mileage may vary, but for this example it’s perfect. Micro-smoothing cleans up the details created by Micro-contrast, so if you notice lots of noise, start sliding it to the right. You will notice a slight difference when looking at the preview as we set Micro-smoothing to 2 for this example. Your settings should appear as below:

Micro tab

9. Click the S/H tab. Highlights Smoothing reduces the contrast enhancements made to the highlights (your bright areas) from all the previous settings we’ve adjusted. You’ll mainly see the difference this makes if your picture in the Photomatix window has some noticeable ‘halos’; increasing the setting helps to reduce this, but for this example it’s not applicable. Since our picture instead contains lots of dark, shadowy areas, we do care about the Shadows Smoothingoption, which will help cover up some of the noise. Take a closer look behind the wheel in the Photomatix preview:

Shadow noise

See all the white specs? That’s noise that we have to get rid of, so let’s pump up the Shadows Smoothing slider to 95. Check out the difference below:

Increased shadow detail

10. Shadow Clipping will also help to reduce any leftover noise, but it doesn’t look like we have much more to worry about for this picture, so click Process:

Process

11. After the changes are applied, the final picture will appear on screen. Now, go to File->Save As, save as a JPEG or TIFF, and do with it what you please.

Some Tips:
To make the resulting HDR look as cool as possible:

  • Shoot RAW to catch all the necessary detail. RAW images are uncompressed, and allow more ‘play’ (adjusting exposure, changing color temperture, etc.) than do JPEGs.
  • Shoot at the lowest ISO possible for your camera to reduce any noise, which will be greatly enhanced when creating an HDR. The RAW picture from this example was shot at the lowest my camera allows, which is ISO200, and we still saw some noise in the shadows.
  • Shoot on a tripod! This is not a requirement, but will allow for greater details in your HDR as you can capture multiple exposures of the same scene but at different shutter speeds to capture more shadow up to more light, which allows for even more detail in your HDR. I rarely shoot on a tripod during the day, but it’s definitely necessary at night.
  • Run the HDR you’ve created through some post-processing, mainly to sharpen the image (Unsharp Mask in Photoshop) or to adjust curves and stuff. I also like to give my HDRs a cross-processed appearance, which would make this picture look even cooler, and which is exactly what I did with the final image.

Thanks for reading! Any questions or comments? Please e-mail me! 
chris@daifukusensei.com