Friday, May 18, 2012

More HDR into the light

typical camera phone phto into the sunThere is one photo that almost all basic photographic advice says never to take “Don’t point your camera at the sun” (or  perhaps a bit more gently advice like, avoid taking you photo directly into strong light). Not only do you risk serious lens flare. The scene in front of the strong light will also be very difficult to expose correctly, because there are likely to be some features blocking the light and therefore in deep shadow producing a very high contrast scene. Most cameras will not be able to capture all the light intensities so their inbuilt light meters will try to find the best compromise exposure. Sometimes that will mean a very dark photo with nice show detail but bleached out areas in the light. alternatively you might get a high key detail in a washed out manner but murky darks,
There is however a photographic technique, available to digital photographers, that can help give decent photos into the light. The technique is HDRi (High Dynamic Range) where by exposures are combined from more than photo taken with different exposure. Probably the easiest way to do this is using a camera phone ap, like HDR Camera+, because the processing of the image will be done in the phone. The apps will take a series of photos, typically 3, at different exposures, then merge the images.Normally you will have preselect the tone mapping options, number and range of exposures before you have the photos. .Make sure you don’t have direct light on the lens, mainly to avoid lens flare, but it will also avoids bleached out areas in your final image. 
HDR Camera+ Bracket Set 2012-05-17_14-33-26_HDR Camera+ 
For those that want more control, there is a lot of specialized HDRi software. I have found Picturenaut a nice utility because it can handle images that are not perfectly aligned (ie they have been taken hand held, rather than forcing you to use a tripod to ensure the images where registered) and gives you several options in how to control the tone mapping into the final image. For a more natural look I prefer to use 5 exposures in my bracketing but with smaller steps between each exposure. The tone mapping method is more flexible, for the image below I used PhtotoReceptor method in Picturenaut.
  Pentax Bracket SetHDR with Photoreceprot tone mapping using Picturenaut
You might have seen some radical surreal HDR effects and been put off by the lurid colours, but HDRi is a technique that can help deliver beautiful photos in otherwise tough lighting situations.
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