Creating HDR Photos using the Canon AEB feature & Darktable

It is very disappointing when you are shooting mixed scenarios where there are dark and light areas all over it. Photos are not right, bright parts are overexposed if you want that the dark ones to appear or dark areas are underexposed because bright parts are looking good. For example a sunset, a moon landscape or even a Christmas tree. Our eyes are used to see in HDR mode but the camera doesn't capture what we see, after all, it is just a sensor.

HDR images are the kind of images that have managed to let you enjoy the dark and bright parts of a scene. They are the product of a post-edition.

In this article, I will explain how to produce an HDR photo taking advance of the AEB capability of modern digital cameras and post-editing with Darktable. Please note I am a Canon user, if I use their terms just translate them to other brands. I am also an open-source advocate myself, do not expect I write for any other commercial proprietary software.

These photos were taken using a Canon 90D using a prime lens 50mm f/1.8. The camera had the D+ enabled (a personal preference; thus, ISO 200 is the minimum I could use). The EXIF information as follows: 1/10s, f/1.8, 50mm, ISO 200.

Shooting with Auto Exposure Bracketing Enabled

Here is the tricky part. You must take three identical photos with different exposure. You will need:

• A tripod or a very steady hand, and
• A remote shooter or use your cellphone if your camera allows you to link it through the bluethood/wifi.

The first thing is to enable the AEB on your camera. There is not an exact formula to know how wide to do the bracket; you may want to make it wider if there is a lot of contrast (too much darkness and brightness) in the same photo.

Configure your camera to shoot remotely and shoot. You will get three photos. Please save the files in RAW format, you will save a lot of headaches when post-editing.

Creating the HDR Image in Darktable

After importing the images, within the lightroom section, just select them and press on the "create HDR" button.

Darktable will create a DNG file with a -hdr postfix. That is the image you want to edit.

Postediting an HDR DNG file Created with Darktable

This is the fun part. Your new HDR file has all the information from the three photos, it just needs to be edited. Here is what I did.

1. Edit the exposition.
   
   The idea here is to make the graph wide enough to cover all the colour areas. Use the exposition bar to increase it. You may also want to use the black correction to move the darkest available colour to the right of the graph. Find a balance where all the areas of the image are clear (without losing details because of the brightness or the darkness). If the photo is still too dark, do not worry.
2. Apply the global tone map module using the Drago operator. A good point to start is keeping the default settings.
   
3. Apply your first contrast module. In this case, use the contrast equalization. You may use the sharpness preset if you do not have noise (usually because you shot using ISO100ish), if you do have visible noise in your picture you may want to use the noise reduction & accentuation preset. In my case, I used the first one as the photo was taken using ISO 200 and that value doesn't provide noise that spoils the photo.
   
4. Apply the second contrast module. The default settings are good, but you may want to play with the detail and increase it a little.
    
5. Next, let's add more life. One of the ways to do this is by adding saturation. Again, play with the values. In my case, a +50  was enough.
   
   You may also want to add some temperature using the white balance. I didn't do it.
6. Finally, apply the tones curve tool. This is a very complex tool. It will allow you to make a range of tones brighter than others. I decided to use a preset of my own that pops up red, blue and green colours.
      

We are done. Here is my final image. What do you think?

Good luck!