High-Dynamic Range

Normal Exposure (0)

Normal Exposure (0)

The human eye is truly incredible.

In daytime, we can easily see details in BOTH the dark shadows and the bright sky.

Take a photograph though, and we end up with either a blown-out sky or dark shadows with no detail to see. 

This is not the fault of inaccurate meter-reading, it's simply a camera's inability to truly capture the full dynamic range of a scene as we humans see it.

Right from the very beginning of photography, it was obvious that a single exposure was incapable of capturing the entire tonal range of daytime landscapes.

Often, we have to decide what we are prepared to sacrifice for the sake of the overall photograph: Will it be the sky or the shadows?

Enter: High-Dynamic Range photography (HDR)

The process involves taking multiple photos (usually 3) of the same subject, but each photo will have a different exposure.

One will be a normal (0) exposure.

One will be over-exposed by perhaps 2 stops (+2) to brighten the shadows up a bit.

While another might be under-exposed by 2 stops (-2) to darken up a bright sky and bring out the details in the clouds.

We can achieve greater dynamic range in a scene by combining as little as 2 exposures, and many people will shoot even more so they have a greater palette to work with during processing.

Once in the computer, these different exposures are blended together to create one single image which shows much greater details in the highlights, the shadows and everywhere in between.

This new HDR image can be made into something which is either realistic-looking (where it looks like a regular image) OR it can be over-processed into an image that borders on the surreal and psychedelic.

It all depends on the software being used and what we personally want our final image to look like.

In this page's slideshow example, I used multiple images: my original exposures (spots and all), an image a typical HDR-program might create on it's default settings and the finished product (cropping included).

When it comes to the blending of the different exposures, I often find that some HDR programs give me too surreal an image to work with, especially in this case.

There's usually a heavy contrast to the blended image, with a very noticeable halo around the edges of trees/buildings and the sky looks just awful and unnatural. If I were to work on that image, those are all problem areas I will have to constantly monitor and repair as I work through the image.

I find it's much better to blend the exposures yourself to get something more natural and yet, there are times when I am having a particular problem blending a complex image that a program actually does a perfect job of giving me a good base image with no heavy contrast or halos. Go figure.

My cameras are set not to record in JPG, but rather the RAW format.

RAW is the complete and unprocessed image file that a camera's digital sensor records. 

It's a flat image, dull and rather devoid of color.

Don't be fooled though. Once we begin processing a RAW image, that's when we see all the magnificent detail and color.

The downside to RAW is that it needs to be processed to bring things out and RAW is a VERY LARGE FILE in comparison to a JPG.

JPG takes all the information the digital sensor records, throws a lot of it away to save space. Afterwards, it will compress the hell out of what's left to create a final, much smaller image file that's easy to share with others.

Unfortunately, once this information has been discarded... it's gone forever.

Since RAW keeps ALL the information intact, it can still be used as software capabilities continue to evolve year after year. Our RAW file is along for the ride, limited only by the original camera and lens we used.

The JPG is forever locked into the moment that it was created, with little ability to be improved in the future. Those blown-out skies, quite possibly recoverable with a RAW file, are blown-out forever with a JPG.

"Remember, not everything is a picture. A good eye can edit before the shutter opens."

Craig Coverdale

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