Monday, July 18, 2016

PhotoProject :: Dynamic Range & capturing what you saw

Cruise Ship in the last of the day

As I waited for the sunset, I watched a cruise ship on its way north along the inland passage. _IGP8201 - original exposureThe white ship was catching the golden light, but a long way away. The distance was very hazy but there were a few clouds. Should make a great photo right! Well not really, and its a little complex but the camera auto exposure  is trying to get an average (grey) exposure. However the scene as seen by our eyes has some very bright things like the ship and some heavier darks amongst the foliage. If you like histogramsimage you can see rather than being a nice bell curve, the tones peak and trough. Further the camera hasn’t really recorded the brightest golden light and the darkest dark. _IGP8201 - Over Processed LookThey are instead “blown out” or clipped(meaning they are just either totally white or totally black). The result of averaging the exposure across this wide range is most often a flat and murky image, and generally disappointing colour.So what can you do about it. The lighting clearly was richer and more colourful, so the tendency is to go for the brightness (or exposure) slide and then also increase saturation. However this usually makes for a very fake look (to the layman its over “photoshopped” even though photoshop was never used).


There are better ways, _IGP8201 - RAW image with tonal adjustmentIf you have a camera that can record in RAW, which simply means the actual sensor illumination reading and all the camera settings. If you also have suitable software to render the image, such as lightroom you might be able access the greater range of light.  However you will be limited to the range of light and colour you are able to reproduce on your screen or printer. You have to stretch the exposure to get all the levels of tone and colour into that range. I once created my own pre-set call SDR+ (Standard Dynamic Range Plus) but I find it just as easy to tweak the basic sliders.


The second well established method is HDR (which stands for High Dynamic Range)._IGP8200_1_2_Detail Preset 1 in Atershot Pro HDR Merge The simplest way to think of the process is taking three of more separate exposure from under exposed to overexpose. These three or more images are the merged together in such a way to make up a broader range of illumination (something more like our eyes will actually see). There are a number of specialist packages that can undertake this merge. Then there is generally a second process that “tonemaps” this extended range back into the reproducible range. I like this technique but it is getting a bad reputation for being overdone (laymen might sometime call this the “fake HDR look”), because the majority of folk take one of the default pre sets which often overdo the level of detail and intensity of colours.

They is an alternative, rather than choose a default tonemapping _IGP8200_HDR Efx pro with OnOne finishyou can often take the extended bit depth file (usually as a .tiff or .psd file) directly into your favourite software and do the tonemapping manually yourself, The Image at the top of the top of this post ws created in Aftershot Pro HDR Merge but instead of using the pre sets I tweaked the tonal range only slightly avoiding the halos around the trees and unnatural sky. The photo on the right was created with Nik’s software’s HDR Efx pro but finished in OnOne 10 effects to protect the sky but darked the sea and add a big softy vignette.

So there are several ways to expand the dynamic range to better match what you saw, only you must take care not to overdo it. I’ll let you choose which are over baked.

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