Love it or hate it, HDR Tonemapping
Tone mapping is an image processing technique used to approximate the appearance of HDR images. Forms of tonemapping precede digital age, and similar techiques were promoted by the famous photographer Ansel Adams
. The technique became popular with digital cameras, as with every generation of digital sensors, dynamic range increased dramatically.
Multiple (bracketed) files can be used to create tonemapped images, but currently it is possible to create good tonemapped images from only one RAW file. There is only one downside, and that's increased noise. Since sensors evolve and each generation will bring less and less noise, it will be the best solution.
You may ask: why you're not using Bracketing
Bracketing is an excellent feature, just set 9 exposures separated by +0.3 EV and you're done. In theory, yes. In practice, clouds are moving, tripod is not so stable, people will enter the frame etc. Sure, if all these issues are not an present, i will use Bracketing!
This tutorial will focus on creating a Tonemapped HDR
image from a single RAW
file by extracting several exposures. It can be done with a single JPEG file but dynamic range is low and quality will be severely degraded.
The original image is a 30 second exposure of St. Stephen's Cathedral
(Stephansdom) from Vienna, Austria.
HDR Tone mapping will be performed in 2 programs: EnfuseGUI
and Dynamic-Photo HDR
These two were chosen for their intuitive UI. You don't need to be a professional to create a nice HDR image, nor spend thousands on a digital camera. For exposure extraction we will use Adobe Camera Raw but it can be done with any RAW processing software like CaptureNX, Canon DPP, Lightroom, Aperture etc.
As with every project, a bit of workflow management is needed. Therefore we will split the main task into three:
• RAW processing and exposure extraction
(jump to next step if you have bracketed exposures)
• HDR Tone mapping
• Post Processing
Here we go...Step 1: RAW post processing and Exposure Extraction
We will use Adobe Camera Raw as is one of the most used raw converters, but same actions can be performed with other raw processing softwares.
First step, load in ACR (Adobe Camera Raw) the RAW file.
Hit the "default
" action and head on to "Camera Calibration
" tab. Under "Camera Profile
" chose one profile which best describes original exposure.For this tutorial "Adobe Standard" profile was used. It is important to perform this step to each exposure!
After proper profile was chosen, jump to the first tab "Basic
" and head down to "Exposure
". We need at least 5 exposures from the original file, so modify Exposure Value to -4 and then to +4 to see "hidden" details.
Set Exposure value to "-2" and save image. Open the file again in ACR, set profile and Exposure Value to "-1". "Rinse and repeat" for original exposure, + 1EV and finally +2EV.
To quickly identify the image, i am naming the exported files as follows: "-2 EV" to "m2", "-1 EV" to "m1", zero for "original exposure", "p1" and "p2" for "+1 EV" respective "+2 EV".
After this step is done, you should have 5 images, each corresponding to following EV Values:
|-2 EV | -1 EV | 0 EV | +1 EV | +2 EV|.
Below you can see a composite images from all exposures.Advanced
: White Balance can be corrected on each exposure, you can add more contrast or even some noise reduction, but it's not mandatory. Don't forget to perform these tasks to each exposure!Step 2: Tonemapping the image
I've got the images...now what!? Now we need the softwares which will blend these exposures.EnfuseGUI
EnfuseGUI is an open source package which will blend exposures into one single image. It's free and the results are excellent. It's a bit "spartan" when it comes to features but hey! it's free!.. and the most important thing, good image quality!
EnfuseGUI is more of an "exposure blending
" than a typical HDR Tone mapping program, but some times it can give you better results than a typical HDR program.Download
and install EnfuseGUI, and start the program. GUI is very intuitive and easy to use.
Start by dragging aforementioned 5 exposures into EnfuseGUI's window, and modify bracket count
to 5 images. If you have more exposures, don't forget to modify bracket count to the same number as your images.
" button and start playing with "Fusion Options
" like "Exposure
etc" and then hit "Enfuse
" when you like the preview image. Additionally, you can create several "Preview
" tabs, to quickly compare different settings.
Default settings have been used and the output is displayed below (mouse over for original exposure):EnfuseGUI
results are subtle
and do not create over saturated images or "halo's" around objects. Excellent prints can be obtained from EnfuseGUI's outputs as the image is not over processed. Hint
: you can safely submit "enfused
" photos to photo agencies.
But, if you're looking for more contrast, saturation or just a different approach to HDR, head on to our next contender.Dynamic-Photo HDRDynamic-Photo HDR
belongs to "typical" HDR packages that render "eye-catching" images, focused on saturation and micro-contrast. Even though Dynamic-Photo HDR
is not free, it offers many features into a reasonably priced package. It offers much more than Enfuse
, but these come at a "price".
" images can be easily rendered but at the same time ( if you're not paying attention) some results can go straight to recycle bin ( due to noise, over saturation, too much processing).
As installation is straight forwarding with few to no options, start the program and choose from menu "Create New HDRI image
First screen will let you chose between four processing modes, each with it's own result. For the purpose of this tutorial we will chose "Complex HDR function"
Similar to Enfuse
, you will need to load all exposures ( -2 to +2) by pressing "Add Images
" (or by dragging into the window).
After all images are loaded, correct exposure value for each picture. "Guess EV
" can be used but it will not chose the correct EV but close. Select each exposure, eg. p2.jpg and correct it with the slider, p2.jpg should be "+2 EV. Chose from "Raw processing options
" auto and hit OK.
Next window, will ask you to align images, which is very useful in case of bracketed images. In our case, with all exposures from one raw, there's nothing to align. It can be bypassed if you uncheck "Align files in the next step
Next step is "HDR Fusion", as we enabled "Complex HDR fusion" on the first window:
HDR image creation is an intermediate step, just before tone mapping the image.
It is almost useless to explain sliders in the current step. A preview window will show the effects of Iterations, Brightness or Microfocus etc. once you are modifying the value using the sliders.
Once you're reached a conclusion, move on to next step, Tone Mapping the image.
Things get rough within this step, as this is the border between a good image and a "recycle bin" candidate.
After HDR step is done, you are presented with "Tone Map HDR image
" option. Chose "Tone Map HDR image
" and as in previous step, a similar window will appear.There is no template that will fit all tastes!De gustibus non est disputandum!
As an example, i like to use "Ultra Contrast
" profile most of the time but with a few changes:
• lower "Dramatic light radius"
• lower "Dramatic light strenght"
These options will create "halo's" around high contrast zones ( eg. white clouds on blue skies), lowering these two options will fix it ( though decrease dynamic range)Filters:
•Sky filterNotable options:
Except "Sky filter
" i prefer to do aforementioned three filters in Photoshop. De-Haze
and Add Clarity
are just Unsharp Mask
increase. I would like to have more control on filters and unsharp mask.
Much different from EnfuseGUI
, here's the result from Dynamic-Photo HDR
The output is very different from EnfuseGUI
, and at this point you will ask the question "Why we should use Enfuse at all?
It depends totally on your tastes and expectations! Some images will fare better with EnfuseGUI's subtle render while other will excel with Dynamic-Photo's rendering engine.Post processing
If you are satisfied with the result from these two packages, then you can stop here. But, if you are an elitist, some post processing will be required. What's the target for this image? Web? Print?
If it's web and low resolution then you're probably fine with current output, but if you'd like to print it or submit to photo agencies, some further work has to be done:
• Noise reduction
( Hint: Topaz Denoise, Nik Software Dfine will do the job)
( be careful! as photo agencies do not like sharpened images)
Keep in mind that there is no template for a successful photo but try to explore all options!
Other HDR images in my portfolio: Good luck and good light!