# HDR - What exactly is it? And how is it achieved?



## tevo (Nov 20, 2010)

i see them all over the net, and when used properly i love them

and yet, i know little about them


how are they created / shot / edited?

any information is welcome / much appreciated!


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## mjhoward (Nov 20, 2010)

HDR is High Dynamic Range.  It uses multiple exposures to capture all the Dynamic Range of a scene.  This is usually accomplished by setting the AEB, Auto Exposure Bracketing, on your camera.  Generally, people use 3 exposures (more can be used as well as only 2) and each exposure is either under or overexposed to capture highlights and shadows.  Once you have captured your exposures, the are loaded into software like photoshop (or a free one like qtpfsgui) and they are 'merged'.  Once you have obtained your HDR, it must be tone-mapped so that it can be viewed and displayed by your monitor.  There are many tone-mapping algorithms and the are all capable of achieving different looks.  They all essentially convert and HDR image into a tone-mapped LDR image.


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## tevo (Nov 20, 2010)

yeah, i just got photomatix and am currently messing around with it, its pretty interesting. are ALL of the exposures either under or over? or is there a (for instance) -2, 0, +2


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## ann (Nov 20, 2010)

the range of exposures will depend on the light,  it is possible to have 1 over and the rest all under, or the other way around, or 5 or 6 or either side.

It is a matter of making enough exposures to cover the DYNAMIC RANGE of the scene.  

I tend to use 1/3 adjustments or maybe 1/2 stop, but that is personal decision, others may deside to use full stops, again, what does the scene dicate.


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## tevo (Nov 20, 2010)

the dynamic range, meaning it peaks on either side of the histogram?


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## ann (Nov 20, 2010)

the dynamic range means how many fstops are needed to cover the lighting conditons . I.E. the range may be 15 stops and the sensor will record 6 or 7 with one exposures.

you can think of shooting from shoulder to shoulder when you look at the histogram.

you neither want to block the shadows or clip the highlights


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## tevo (Nov 20, 2010)

ah, okay. thanks much!

does the Nikon D7000 have AEB?


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## Bynx (Nov 20, 2010)

tevo said:


> ah, okay. thanks much!
> 
> does the Nikon D7000 have AEB?



For the price it cost, it better have.


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## tevo (Nov 20, 2010)

Bynx said:


> tevo said:
> 
> 
> > ah, okay. thanks much!
> ...


 
that was my feeling LOL


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## Bynx (Nov 21, 2010)

AEB is 3 exposures, maximum 2 stops apart.


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## KmH (Nov 21, 2010)

It's amazing it can only do 3. The next step up, the D300s, can do 9.

Of course done manually, you can do as many as you want.


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## WesternGuy (Dec 24, 2010)

Thereis also a piece of Hardware that will work with Certain Canon and Nikon cameras to extend the range of HDR images that you can shoot. An overview is here... https://www.promotesystems.com/products/Promote-Control.html and a review can be found here... 
Gear Review: The Promote Control (A Canon HDR Photographer&#8217;s Story) | Brian Matiash PhotoBlog

It is an interesting peice of hardware, however, it does not work with every Canon and Nikon DSLR.

Regards,

WesternGuy


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