32 bit HDR

When we take a photograph the camera does it’s best to capture the full dynamic range but most cameras only capture a range of around 6 to 10 f-stops at best. On the other hand our eyes are extremely adaptive, they’re more sensitive to intensity rather than colour and it’s estimated that our eye can see over a dynamic range of nearly 24 f-stops. So what the camera captures is not exactly what we are seeing.

Take for example this image. Taken as the sun was setting, I remember that there was colour and definition in the clouds and I could see perfectly clearly the inside of the shelter, including underneath that bench. Yet, the camera struggles to give me what I saw.

Our eyes see details in the Shadows as well as the details in the Highlights. But a camera with its limited dynamic range struggles to capture the same amount of detail in the scene. In the end we are left with the choice of – the image (+2 Ev) to get details in the Shadows or under-exposing (-2 Ev) to get details in the Highlights. But we won’t get both the same way our eyes can.

Alternatively we could try to fix the image by Dodging or Burning but there is simply not enough detail in the picture to cover the whole tonal range.

And this is where HDR or High Dynamic Range comes in. If we could combine all the exposures into one image, using the best detail from both the Shadows and Highlights, we would have enough dynamic range to display the image as we saw it.

Over the years HDR has been used to give those surreal images that many photographers decry with a vengeance. Personally I have nothing against the surreal images, there are some great ones out there, I’ve even done some myself. The way I look at it is, if an HDR image is good enough to be hung in the Smithsonian, and one has, then HDR can’t be all wrong. So much so that many camera manufacturers include HDR settings in their camera menus these days. My Pentax K-30 has four HDR settings, from Natural to Surreal, each setting taking a bracket of three images. However, as I mainly photograph land and seascapes I tend to go for the more natural look in my HDR images.

I have used many of the HDR programs available, some well-known, some not so. PhotoMatix, SNS-HDR Pro, NIK HDR EFEX, Dynamic Photo HDR and currently my main weapon of choice, Machinery HDR Effects. In all cases the programs mentioned can deliver a natural looking HDR image, You just have to make sure that you go easy with the various sliders and settings in each program.

Recently I watched a video about some of the new capabilities of Adobe Lightroom 4.1, which I use to develop all of my RAW files. I don’t really use Photoshop much these days as most of my post processing is also done in Lightroom. One of the great new features is the ability to process 32 bit HDR files directly in Lightroom, just as though we were developing a RAW file, and the great thing is the process is quite simple.

Obviously you need Lightroom 4.1. Adobe would recommend Photoshop to do the HDR bit but not everyone can afford the high cost of Photoshop, including myself. Fortunately the makers of PhotoMatix, HDRSoft have created a low cost plugin for Lightroom that allows you to create the 32 bit file and then bring it back into Lightroom automatically for final editing.

How does it work. First you need some bracketed photographs. Select them all within Lightroom, right click, choose Export and then Merge to 32-bit HDR. Lightroom and the plugin will do their thin and at the end Lightroom will add the new 32 bit file to the catalogue

Now comes the hard bit. Choose the Develop module in Lightroom and do the following;

Highlights –100
Shadows + 100
Clarity + 100

That’s it, nothing else to do. In reality sometimes you don’t need the Clarity set to +100, or the Shadows so high.

The best way to check is with the Histogram to make sure you are getting the full Dynamic Range

So what sort of results do you get.This bracket of 5 images from –2 to +2 was taken at Weston-super-Mare and processed using the Lightroom method. Compare it to the same image at the top of the page which was taken at the same time, but only one photograph was taken.

I think you will agree with me that the HDR image shows definition in the Shadows as well as the Highlights and does not resemble the surreal images that are so often associated with HDR Processing.

I’d like to leave you with a couple of more images processed the Lightroom way. The first one is a 3 exposure bracket, –2 to +2 photographed in the cloisters of Gloucester Cathedral. It was early morning (07:30) and very dark outside because of heavy rain. The spotlights were turned on to pick out some of the details in the roof and the alcoves

The second one was taken on the beach at Prestatyn just as the sun was setting. Once again it was a bracket of 3 images from –2 to +2.

This process using Lightroom has been getting very good reviews in HDR circles and I can understand why after trying it for myself. I am impressed with the simplicity of the process. I spend less time creating the final image the results look far more natural. Noise levels, which have always been a by-product of HDR processing, are substantially less in the images I have processed so far using this method.

Related articles

• HDR photography (andrewyun50.wordpress.com)
• Rick Sammon: Realistic HDR images (dpreview.com)