HDR Photography – The Guide
High Dynamic Range photography or HDR photography is an advanced set of photography techniques that play on image’s dynamic range in exposures. HDR Photography allows photographers to capture a greater range of tonal detail than any camera could capture thru a single photo.
While many imaging experts regard HDR photography as the future of digital photography, the discipline has long been in existence.
HDR photography is present in many pictures taken through modern day digital cameras. The truth is, if you are a real photography enthusiast then there is a great chance that you have taken at least one photo exemplifying HDR photography.
The real functions or even executions of HDR photography may be debatable. But no matter which website or source you consult they will always say it is a technique that employs the great use of exposure range to get distinct values between light and dark areas of the image. Its real intention is to create an image that accurately characterizes the intensity levels found in natural scenes. If you ever wondered why the picture you took was different from the scenery you actually saw, then maybe it’s time for you to learn HDR photography.
HDR Photography is the technique used to capture and represent the full (as possible) DR found in a scene with high perceptual accuracy and precision. To remember things better, think of the 3S: sunlight, shadows and subjects. These are the things that make an ordinary picture an HDR image.
The history of HDR Photography
While the technique is more commonly used now to create astounding images of art, fashion and landscape photography, HDR photography’s humble beginning is ironically designed to capture a rather fearing, shocking and destructive image – nuclear explosion.
Charles Wyckoff developed HDR photography in 1930s to 1940s. He is genius who took the 1940s Life magazine cover of nuclear explosions – an image that would later change the world. Of course the technique didn’t have the acronym HDR before, but the principles remained the same.
A deeper and perhaps more scientific understanding of HDR photography and imaging was first introduced in 1993. This was done by playing on two established photography elements: tone mapping and bracketing. A complex mathematical theory regarding differently exposed images of the same subject matter was then released two years after. Paul Debevec, a computer graphic researcher, applied this theory and combined several differently exposed images to produce a single HDR image was accomplished. Talk about putting a lot of science and even math to discipline.
Today, things are a lot easier. Thanks to the wide selection of portable and digital cameras as well as easy-to-use software, HDR is no longer limited to people studying nuclear explosion and computer graphics technology. But the technology on image capture, storage, editing and printing devices still has some limitations. And since each of these elements affect the DR of image; we need to study them if we want to get an HDR image with superb quality.
Theory Behind HDR photography
There are two theories behind HDR photography. And as the technology around HDR photography evolves so is the discipline itself. But if one wants to take HDR imagery seriously then he must first understand the concepts and theories that make up this discipline.
The most fundamental of all HDR photography theories is to take multiple shots at varying exposure levels of a particular subject. A special computer program will then combine the images together into a single image. This is just an incarnation of the original theory during the time when there are no digital cameras and advanced computers and programs were nothing more than a work of science-fiction.
The second theory is the one that capitalizes on the RAW processing software to create various exposure levels of the same image. Modern Digital SLR camera and a lot of the Point and Shoot models allow photographers to capture RAW images. A RAW image or file is the data captured by your Camera’s sensor that is not processed yet and therefore does have color information. You can manipulate this file, adjust its color, lighting or while balance.
How to gather data for HDR photographs
Taking the images is the first stage in HDR photography. You can use a simple point and shoot camera or a fully configurable digital SLR camera camera.
In both techniques you will need a camera with configurable exposure settings. All DSLRs and most point and shoot cameras have this. Certain SLR cameras have bracketing function which makes it easier for photographers to change exposure settings.
For starters, you can use the following setting: ISO 200 and Aperture Priority Mode. And as they say good things come in threes, you can take picture with three different exposure settings: EV 0, EV -2 and EV +2. You can experiment more on these but generally speaking, the more exposure versions you can have, the better your final image will be.
Oh, and obviously, It is recommended to use a tripod when taking HDR photo. This is because tripod stabilizes the camera and you need to get the clearest image you can get since you are experimenting on exposure values. The best way to do this is to use a shutter remote or if your camera doesn’t have one, just make sure you press the shutter button lightly.
Incredibly, the above photo is an Infra-Red HDR photo. Awesome, eh?
|Post processing is the last stage in HDR photography that you can really control. This is where technical skills merge with creative sensibility. And with the introduction of advanced digital cameras and photo editing software, HDR image post-processing is made a lot easier. However, this does not guarantee that having an excellent HDR image will be as easy as clicking the shutter button. There may be times that the three or more images you took with varying exposure values are simply not enough. With this, the only chance you are left with is to do a post-processing of the image.|
Post-processing generally involves color correction, saturation, contrast and brightness and darkness adjustment and other image element manipulation. But in HDR photography we need to concentrate on contrast and brightness and darkness adjustment. Brightness and darkness adjustment is the direct digital translation of exposure manipulation in the picture taking stage. If in the camera you adjust exposure settings, in the post-processing stage you will adjust the brightness.
The main advantage of process is surpassing the limitation of actually configuring your camera in different exposure levels. While some cameras may have eight exposure settings and therefore 8 different images, post-processing can simply give you a limitless number.
After the shoot, transfer the images to your computer. There is a merge to HDR feature in many photo editing software including Adobe Photoshop and above, Photomatix Pro, Dynamic Photo HDR and others.
Post-processing software also allows you to blend photographs with different exposures. This clearly increases the dynamic range of the final output photo. There is also tone mapping which reveals highlight and shadow details in an HDR image made from multiple exposures.
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