Wednesday, 9 November 2011

HDR Photography Tutorial

You either love “High Dynamic Range (HDR)” photography or you hate it. There seems to be no middle ground when it comes to people opinions. My thought is that the mention of HDR conjures up thoughts of grungy, high contrast, unrealistic photos that look more like an artistic rendering of a scene rather than a photograph.

When I decide to use HDR in a photograph, the purpose is to produce a quality photo which is better than that of a normal photo. I use it to attempt to overcome the limitations of my camera and allow for a full range of exposure and colour to “POP” out of my image. The result is a more vibrant image.

The real advantages to HDR photography are as follows:

HDR photography captures higher dynamic range
Let's imagine a situation where one photographs (without a flash) a high contrast scene where the subject is against the sky. Typically there is a problem in the result. Either the sky is over exposed, or the subject is under exposed. This end result does not produce a scene that your eyes actually saw as you stood there behind the camera. Your eyes can clearly see details in both the subject and the sky. However, the digital camera isn't able to see as high contrast as a human eye does. Enter HDR in post processing…
Awhhhh, my son, God luv him. We had climbed up Mount Dumyat in Scotland and he had to pee. So, he decided to pee right off the side of the mountain versus going over in the bushes.

In photography, the goal is often to capture the view and the mood that was seen and experienced. Unfortunately, because of the limitations of digital cameras, some details are often missing in photos. In high contrast scenes, a digital camera isn't able to capture both the brightest and the darkest areas simultaneously. HDR photography offers a solution to this problem.

The high dynamic range and the way HDR photo saves image information, give new possibilities to digital image processing. One can do very strong digital image processing operations to an HDR photo without losing any image information. A properly created HDR photo can include very large amount of image information and therefore give the photographer a possibility to create exactly the kind of photo he or she wants.

HDR photography Can Produce Noise Free Photos
An HDR photo is created by merging several photos that are taken with different exposures. If there are enough exposures, each part of the photo has optimal exposure in several shots. I don't know the merging algorithms of HDR programs but presumably they take best parts of the photos and / or do some averaging between the pixels in different shots and therefore noise is reduced effectively. Anyway, according to my tests HDR makes it possible to produce photos that are noise free even in the darkest shadows.
This is an HDR photo taken at night on Michigan Ave in Chicago. This was one of the first HDR images I ever did. When I saw it I was hooked, minimal noise, nice colours and the detail was impressive.

For the landscape photography the process can really enhance an image and separate your photo from the others. The software options are abundant. Personally, I use Photomatix. I have used NIK software , Topaz Adjust and used HDR in CS5, but I always find myself reverting back to old faithful, Photomatix 4.

Here is a list of HDR programs that you can consider:
HDR Express
Topaz Adjust
Lightroom Enfuse
Photomatix 4
Nik HDR Efex Pro
HDR Darkroom
Adobe Photoshop CS5 HDR Pro
To see a complete review of each program please visit HDR Software’s website once you finish reading about the possibilities of HDR photography here.

OK, now on to the process of creating an HDR image. In this tutorial I will be using a combination of Abobe CS5 and Photomatix 4.0 to get the end result.

The original images
You can use anywhere between 1 to 5, 7 and sometimes 9 photos. It all depends on you really, and occasionally it will depend on the scene. The harsher the contrast, the more photos used seems to produce a better image.

I tend to shoot 3 to 5 RAW images in the field and range the exposure by +/- 1EV. If you shoot one image and decide when you get home that you want to produce an HDR image from the single photo. Your choices are to do HDR rendering on the single image, or, produce 3 to 5 images from the original in jpg or TIFF with a range of exposure. I simply RAW edit the original and use the exposure slider in the RAW editor to produce photos of varying degrees of exposure.

Here are the original images we are going to start with for this example. I tend to shoot a balanced photo and then over expose a few images and then under expose a few images.
As you can see there are 5 images down the left. To the right is the minor RAW edits I made. The larger photo is the original photo I took before I over and under exposed the other four images

RAW Editing
The RAW editing is just simple color adjustments, eliminate any sensor or lens dust, a few tonal adjustments, minor clarity adjustments, a bit of balancing and that’s about it. I do not sharpen the images or prepare them for printing just yet… this is just a cleanup of the original 5 images before I open them up in Photomatix.

Please note that sharpening the images too much in this step will lead to issues once you perform your HDR editing. Leave that to the end when you import the Photomatix document back into CS5.

HDR Processing
Here you have the photomatix screen when you first load the original images. Make sure you check off the box to eliminate ghosting if there is moving objects like clouds in the image.

As you can see down the left side of the screen shot, my settings are there. I generally do not deviate too far from these settings when I am applying HDR on a landscape photograph.
for this image i chose exposure fusion. You can also set the editing mode to tone mapping. I tend to do that with a photo with less contrasting foregrounds adn backgrounds.


Final Processing in CS5
Once I have finished the final editing in Photomatix I reopen the jpg or TIFF document in the RAW editor one final time. This time I run through my final steps of checking balance, colour, clarity, saturation, camera lens correction etc.

I then open up the image in CS5 and perform my final edits to finish the photograph. For this image I felt I had to perform some cloning for the bad ghosting in the clouds, I colour adjusted the green to make it pop a bit more and i played with the exposure levels to get the overall tonal look I wanted.

Final Image
As you can see below there are two images, the first photo is the original properly exposed image and the second one is the final HDR image.


Now, here are a few more HDR Images from that morning on Puslinch Lake near Cambridge, Ontario.



Everyone has their own method of producing an HDR image and they may use different software than I do.

Find out what works for you, master the technique, and enjoy the end results.

Happy Shooting,

Kev