Way back around when I first joined Active Rain I did a bit on Dynamic Range, in hopes of illustrating one of the common limitations of current imaging devices and some ways to work within those limitations.
Of course, few of us are ever satisfied with limitations of any kind and I wanted to share with you one way to address DR in photos.
I'm talking about HDR of course. In simple terms HDR is a process where a camera in a fixed position (such as a tripod) is shot multiple times at different exposure levels. Using specialized software, the images are then blended together to produce a final output image which (hopefully) incorporates the extended range of the image re-compressed into a standard image.
Sound complicated? Well, it is to some degree...in fact there are many professionals that shy away from it purely from a standpoint of difficulty. I'm not going to go into great detail about how it's done today, it's too lengthy a process (trust me it would take blogs and blogs just to cover the basics). But we can at least take a look at an example of what it does and you can decide if you want to delve further into it. :)
Let's take a typical use case:
You're driving along and you see this wonderful sunset. You hop out of your car, grab your camera and take the following shot:
Allright! Except...wait... we got the sunset exposed correctly but terra firma seems locked in permanent midnight.
Ok, ok, we can fix this right?
So we adjust exposure a little bit and...
Ok, yeah! Now we have city and the water properly exposed...
But, oh no!
What's happened to the sky? It looks like something out of the straight to video version of Dante's Inferno.
The city being properly exposed has caused the highlights in the sky to become blown out or clipped.
Drat.
That's limited dynamic range for you.
But all is not lost.
Let's see if we can't blend these back together using HDR.
Voila, HDR to the rescue (btw this is actually the result of three different exposures which is the minimum need for HDR).
There's a little bit of photoshop here but for the most part this is the resulting image.
Notice we have much more even tonal information across the total image.
BTW, you can also simulate this technique to some degree manually by layering the photos and employing masks to blend the various exposures to your satisfaction.
It's not quite as powerful but it works well and is a lot simpler in most cases than current HDR process.
Cheers, -B
Professional-Photographer
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