How to create an HDR ?

How to create an HDR?
The normal way is to make a minimum of 3 images with bracketing technique,
one underexposed ( -1.5 to -2.0 ), one overexposed ( +1.5 to +2.0 ) and one correctly exposed.
And if possible, preferably on a tripod.
The images are then loaded into the HDR program – aligned if necessary – and after setting parameters, converted into an HDR image.
Exposure bracketing ( AEB ) can be adjusted on most camera’s for taking 3 or 5 shots, and normally you could choose from a few sets of preset exposure corrections.
For this, we advise you to consult the manual of your camera.
Since you are making strong image manipulations,it’s a must to shoot RAW.
Then load these images (if possible in RAW, TIFF otherwise, never JPG) in an HDR software.
There are many available, and certainly in the open source segment.
Try searching Google for HDR.
At this moment I use Luminance HDR, witch is available @ http://qtpfsgui.sourceforge.net/
All available HDR software has its own method and possible settings.
Trying is the key.
Digicrea would not be Digicrea, as I would not have been experimenting and searching for a good but simple open source workflow to create HDR’s.
While experimenting, I noticed a few difficulties making HDR images.
– Making recordings with the bracketing technique is cumbersome.
– Basically, you need a tripod (not something you always have with you).
– In many cases you can only imagine afterwards, from which image you would like to make an HDR.
You could try to create HDR’s from only one image, and that works also.
But this way, you don’t get the same high dynamics in lighter or darker areas in your image.
The solution for this is to software correct the exposure afterwards.
This technique has many advantages, you can apply HDR on any image taken afterwards,
and also, you can make HDR images from fast moving objects like sport cars, motorcycles, etc…
Try that with your camera and bracketing – exactly, almost impossible.
So we have done experiments with the bracketing method, and also with exposure corrections applied during RAW conversion and with an editing program.
This showed that HDR images created with the bracketing technique, across software corrected HDR images, were not that much better.
Personally, I find making HDR’s a very invasive technique to start with, so I do not think that the bracketing technique really has an advantage over others.
Though many photographers in this area do not have the same opinion, I think it is worth to do it once “differently”.
Is that not what we stand for photographers?
Creative and Artistic?
Below the workflow for creating HDR yourselves thru the “alternative” way.
The software used is RawTherapee 4.2.73 and Luminance HDR 2.4.0


Workflow ( click the sample pictures to get a bigger view ) :
Open the RAW image file in RawTherapee from which you want to create an HDR.

RT-exposure-compensation
Optionally, you first click on “auto levels” (first tab exposure) and save the file as TIFF,
through the lower left button “save current image” under the filename “normal” or something like that.
Next do an adjustment of the “exposure compensation” to -1.5 or -2, and save the file with the button “save current image” under a different name (or something negative – ditto TIFF)
Afterwards repeat the previous step, but with a positive “exposure compensation” to +1.5 or +2, ditto save under a different name.


3101-164836-X100-Fort-Brasschaat-correction-slides

You will end up with three images, one under exposed, one correct and one over exposed.
You can repeat these steps as many times as you HDR program allows to upload images.
Since creating HDR’s requires much memory of your computer, it is best to start with 3 files to try. Afterwards you can still experiment with more.

 

 


 

LuminanceHDR-load-imagesThen start your HDR program, in this case Luminance HDR 2.4.0.

click “new HDR image” and then select the already prepared files.
Because the exposure compensation is applied afterwards, Luminance HDR doesn’t find the EV (exposure values) in the EXIF of the files.


LuminanceHDR-set-exposure

¬†You can set it yourselves for each image, on the right side with the slider “selected image exposure”.

“Auto Align Images” is not necessary, you may possibly have to experiment with the “auto anti-ghosting”.
Click then next.

 


 

LuminanceHDR-set-profileIn the next menu, then choose a profile.
It’s hard to say what the effect is of these profiles, so experiment.

 

 


 

LuminanceHDR-set-parameters-saveThen choose an “operator”, the effect of the different operator’s can be visually identified at the right side of the program.
Each of these operators has its own set of parameters that can be set to apply the effect, different, weaker or stronger.
Again, it is therefore to experiment.
In time you will find a personal style, and you can use your settings over and over again, or variations on it.

Do not forget to set the desired “result size” of your image in HDR – I always choose the largest possible.
Then click “tonemap”.
The result of this operation can be saved from the button in the toolbar above using “save as …”
Afterwards you can open with your favorite image editing program,
and possibly make some personal adjustments such as a watermark or something else.
I myself use Gimp Partha Portable.
and Voila!
Your first HDR.

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