HDR Photography explained

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What is it? Well HDR is the abbreviation for High Dynamic Range photography. Its a rapid developing technique that enables photographers to record an extremely wide range of tonal detail than any given camera could capture. With the help of software (Photomatix Pro, Photoshop CS2 etc.) its a technique that allows the photographer to combine/super-impose a series of bracketed exposures into a single image which encompasses the entire tonal detail of the entire series. Of course the software uses several algorythms that has been specifically developed, but I won't go into the detail of the maths in this article. Here is an example: Your standing under the arch with amazing detailed architecture and you want to photograph your family sitting at a coffee shop table in direct sunlight a few meters away. You have two choices: You go for a fast shutter speed to prevent your family being completely blown/burned, but then you loose the detail of the arch, normally it will come out completely black. Of course if you go for a slower shutter speed, the arch detail will be captured, but the family will be overexposed. Damn, what do you do!? The reason for this? Real-world conditions contain light ranges that exceed a 50,000:1 dynamic range. Your camera is usually limited to around a 300:1 dynamic range. The solution is to take more than one exposure and then super-impose the images...But, here is where the fun starts. You can use HDR imaging techniques on any subject or under many different conditions (not just the example I've mentioned above). The MOST important criteria is that the subject must be STATIC! You can generate some pretty exciting photgraphic effects from a normal scene, some bordering on the surrealistic! Now I will give you a step-by-step guide of how to take HDR images: You will need the following few simple things: A digital camera, preferably a DSLR but a good point and shoot will do the job. Remember, you need to be able to change the shutter speed manually. The focus can stay auto but if you can set it on manual do so A tripod; to function correctly, HDR needs to take different pictures of the same scene. If you do not want any motion flow, take pictures of stationary objects. Software requirement. Latest edition of Photoshop (its quite expensive) or Photomatix, (available free download for Windows, http://www.hdrsoft.com/download.html). When all this is in place do the following: Put your camera on the tripod. Place it firmly because you’ll have to touch the camera to change the speed and this can make you move it, and then, well you wont be able to get the HDR you were hoping for. Its also advisable here to get yourself a remote to activate the shutter release for your camare, as this significantly reduces any possible movement. Together with the remote and the automatic bracketing exposure function of modern SLR cameras, this becomes quite easy. After selecting the subject you wish to shoot, prepare everything as if you were only going to take one picture. Prepare it to your taste or what ever is you want to acomplish. Set your primary exposure and speed. We are going to call this master setting 0. After this is complete and you have everything set up you are going to take let’s say 7 pictures (3 pictures up from 0 and 3 pictures down from zero). Don’t panic is quite easy. Here is an example: If the settings for picture 0 is: 1/125 and f/4.5 The settings for the remaining pictures are as follows: * Picture +3: 1/250 f/4.5 * Picture +2: 1/200 f/4.5 * Picture +1: 1/160 f/4.5 * Picture 0: 1/125 f/4.5 (YOUR MASTER SETTING) * Picture -1: 1/100 f/4.5 * Picture -2: 1/80 f/4.5 * Picture -3: 1/60 f/4.5 Notice that the aperture setting (F/) stays the same. This is quite simple: if that value changes also will you Depth of Field which will cause you focus to change also. Now that you have taken all your pictures you use Photomatix to make HDR version and do the tone-mapping! To see some examples of HDR photography visit my photoblog @ http://memyselfandmyslr.blogspot.com/