How I created this HDR image of the Qutub Minar

In this brief tutorial, I’ll outline the post processing steps I employed on an image I shot in Delhi recently.

Before I get into the steps, let me answer the question – why HDR? The primary goal of an HDR image is to show a dynamic range greater than what can be captured by a camera sensor under normal circumstances. This means, to show a tonal range of beyond 5 stops. Even though I reached the Qutub early in the morning, it was 10 am by the time I started shooting.  Sunny mornings generally present challenges to the camera sensor. I used a 5D Mark III, whose dynamic range I am not at all pleased with. I loved the scene here – yellow/green lawn and the majestic Qutub MInar against a blue sky. I really wanted to do justice to what I was seeing in front of me, so I decided to shoot a HDR.

But how would have the shot looked like without a HDR? Here is the output of a single exposure, without any processing:

Qutub Minar by Pratap

Here are the steps I followed:

Step 1: Auto-bracket 5 shots. With the 5D Mark III, Canon has finally given us an option to bracket more than 3 photographs in a non 1D body. I have the default bracketing set to 5 exposures. Of course, tripods aren’t allowed inside, so I set the camera to burst mode and took 5 auto-bracketed exposures in one go. Ideally, you should use a tripod to auto-bracket exposures meant for HDR processing.

Auto-bracketing for HDR

Step 2: Merge to HDR in Photoshop. For this step, I obviously was back at home in my digital darkroom. Yes, I could have done it on a laptop on the road as well, but I prefer working on my Hackintosh with 16GB RAM and 24″ calibrated monitor.  But why Photoshop? Well, the choice of post processing software is just a matter of personal preference. I generally use Photomatix. But for this image, I wanted to try out HDR Efex Pro by Nik software. Also, Photoshop does a pretty good job of aligning the source images at the time of merging. This was important, because these exposures were made hand-held.

I imported the files to Lightroom, and choose Edit In > Merge to HDR Pro in Photoshop.

Edit-in-PS

Step 3: Saving as 32 bit in Photoshop. By default, Photoshop prepares a 32bit version of the merged HDR image. If you decide not to use a third party plugin like HDR Efex Pro, you can use Photoshop itself to tonemap the image within the Merge to HDR Pro dialog. In this case, since I decided to use the Nik plugin, just clicked on OK after Photoshop did its thing of aligning images and creating a 32 bit image. If you think the 32 bit photograph in the screenshot below seems a little weird, that is how it is supposed to look like!

What is tonemapping btw? Here is the definition from Wikipedia: Tone mapping is a technique used in image processing and computer graphics to map one set of colors to another in order to approximate the appearance of high dynamic range images in a medium that has a more limited dynamic range. 

To put it simply, the resulting 32 bit image looked flat simply because it had a dynamic range far greater than what could be reproduced by the monitor. So to get a usable image that you can actually appreciate on display or print, you need to covert the high dynamic range into something more limited – and hence you tonemap.

Merge-to-HDR-Pro

Step 4: Use HDR Efex Pro. It is important to understand what happens when you open a 32 bit image in Photoshop. Not all plugins and features of Photoshop are available for 32 bit images. Photoshop works best with 16 and 8 bit images. However, Nik HDR Efex Pro works on 32 bit files. When you run the plugin, you see various tonemapping styles based on image presets. I picked one I liked and used it as a base to make further enhancements within the plugin. After finishing with HDR Efex Pro, I clicked on OK and the resulting HDR tonemapped 32 bit image opened again in Photoshop where I converted to 16 bit, and saved it as a PSD.

HDR-Efex-Pro

Step 5: Finishing off in Lightroom. Once the image was saved, LR imported the PSD file. I made minor tonal corrections in the Develop module of Lightroom to finish off the processing. This step is purely optional, but I found it necessary to increase sharpening, and decrease the highlights a little. I exported the PSD to a JPG file to be able to display it here.

So there you go – an HDR image in 5 easy steps!

Photograph of the Qutub by Pratap

A photograph of Qutub Minar processed using Nik HDR Efex Pro.

Update: I reprocessed the final image after some of you pointed out halos around the Qutub in the previous version. Yes, halos in HDR images are a problem and one must be careful while editing. Someone also pointed out that I coulud have achieved a similar result with just a single exposure. While it is true to an extent in with respect to this photograph, it is not always the case.

One Response to How I created this HDR image of the Qutub Minar
  1. Vinay Reply

    Good one

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