HDR tutorial

Table of Contents

• Introduction
• What Is HDR?
• HDR Software
• Taking a HDR Photo
• Camera Settings
• Issues
• Post-Processing Work in Photomatix Pro
• Loading Bracketed Photos
• Selective Ghost Removal
• Merged HDR Photo
• Tone-mapping step
• Additional Post-Processing
• Example
• Black & White HDR
• Multiple Tone-Mapping
• Exposure Fusion
• Introduction
• Creating fused images in Photomatix Pro
• Appendix A: Batch Processing
• Appendix B: GUI Tips & Tricks
• Appendix C: Number of exposures and its influence on image quality
• Appendix D: Dealing with halo artifacts

INTRODUCTION

In this tutorial I will try to introduce and describe recently popular HDR photography. I will try to answer following questions:

• What really is HDR photography?
• How to take HDR photos?
• How to process HDR photos? 

I will also tell a little bit about typical problems related to this kind of photography and I will propose solutions on getting rid of them. I will also try to share my own ideas about work-flow and post-processing which I use in my daily post-processing. It means that I will write about realistic HDR photos.

This is a revised version of the tutorial I have posted a few years back on my blog. This version details the HDR processing much more and gives more examples.

WHAT IS HDR?

Many people have a wrong idea about what HDR photography really is. HDR, which stands for High Dynamic Range (what means nothing more but wide range of luminosity and contrast in the scene), is neither a special effect nor a post-processing technique. HDR is reality, it is what we see every day but what isn't captured properly by our cameras. HDR in photography is sort of a trick to overcome limitations of current generations of cameras and display devices. Although I don’t think grunge or overdone HDR photos are always a bad thing (provided it was done on purpose not because of lack of skills in realistic HDR processing) many of the beginners cannot really feel the concept of HDR and their images are full of artifacts like halos, noise and ghosting to name a few (all of them will be described later).

One of the best things I learnt about HDR and tone-mapping in the recent years is that it's the beginning of the process of developing a photo, not the final step. Many people would like to throw photo into Photomatix, process it and share on the net. However, making a good HDR photo requires much more work. HDR which stays for High Dynamic Range means that a photo has much more information about luminosity than a Low Dynamic Range photo (like a single JPG, TIFF or even RAW file). Luminosity is a characteristic we relate to light, not colour. It does have nothing with colour temperature or saturation.

But you probably also know that it isn't possible to display a HDR photo on a typical monitor without a special conversion step known as tone-mapping. That said what you should primarily use tone-mapping for is making sure that details both in highlights and shadows are preserved. You don't need to care about colour temperature or saturation at this stage that much.
Now time for some examples. HDR is trying to solve a following problem. The real-life scene can have contrast of 100.000:1 or even higher. This ratio tells the difference between the brightest (eg. the Sun) and the darkest (eg. deep shadow of a tree) point of that scene. Sometimes the contrast is so high that even our own eyes aren't capable of showing it all and we perceive parts of the scene as very dark or very bright. Just move from a very dark room to the outside lit by the sun. At first everything is almost white and faded then colours become to look normal but look back and everything will be dark, almost black. It's because our eyes have dynamic range of only about 10.000:1 meaning that we can't see details in shadows and lights at the same time.

Another example might be a forest with beautiful light and shadows play, with a lot of dark places and light shafts going through the leaves. Or yet another – a cave. You can try shooting outdoors from inside. In both cases our camera fails – it cannot recognize enough details both in highlights and shadows no matter what its dynamic range is (our cameras have much worse dynamic range than our eyes). And even if it could there is no display device capable of properly displaying such a photo. Who know, maybe one day it will be possible but not yet. Regarding camera's dynamic range, eg. my Canon 5D MK II has dynamic range of about 2.000:1... not really good.

This leads to a conclusion that HDR is in fact a trick, something allowing us to overcome limitations of current devices. It uses photo with much wider luminosity range and it maps it back to the space which is possible to be displayed on our monitors. The last step is done in the tone-mapping phase. There are virtually infinite ways of tone-mapping as you may guess (as there is infinite number of functions mapping from the wide-range to the low-range) photo but all algorithms (known as operators) fall into one of the two categories:

• Local operators (i.e. in a small neighbourhood of a pixel) - they are working on the local features of the image. It means that tone-mapping might work differently for each pixel of the image depending on characteristics of its surrounding.  Local operators are commonly used in HDR software because they produce more appealing images with details and micro-contrast being well enhanced. However, local tone-mapping operators have a few drawbacks. First of all they can amplify noise in the image as software cannot always determine if something is just noise or very small detail so it treats it as detail. When small details are enhanced, so is the noise. Tone-mapping is no exception here. Many sharpening tools must deal with the same issue. Another issue with local tone-mapping operators is they can produce halo artifacts around the edges.
• Global operators – each pixel is tone-mapped in the same way based on some global image characteristics (like eg. luminosity). As you may have guessed this makes these kind of methods really fast (that’s one of the reasons they are used in video games more commonly than local operators) but there might be some loss of detail. The greater the dynamic range of the source image the greater loss of detail is possible.

As mentioned above the main advantage of the global tone-mapping operators is their speed. It is enough to say that global operators are much more frequently used in real-time scenarios (like video games) but local operators produce much more appealing results as they enhance details and contrast locally taking more characteristics into account.

HDR SOFTWARE

First it is necessary to decide what software to use. At the moment there are a lot of options here, each of the programs offers slightly different capabilities and has different tone-mapping algorithms what results in slightly different output (that’s why many photographers own more than one application). Also some applications deal better with particular scenes than the others but fail at some other scenes. Below I listed a few most popular programs:

• HDRsoft Photomatix Pro – one of the most popular HDR software available on the market.
• Nik Software HDR Effex Pro – software from Nik company working as a Photoshop plugin. It uses Nik’s typical GUI and U Point technology.
• Adobe Photoshop CS5/CS6 – for a few years now Photoshop has HDR plugin available out-of-the-box. Even though there was pretty big improvement in CS5 it is still considered worse from dedicated software.
• Oloneo.

Personally for all my HDR photos I use Photomatix Pro 4.2 (+ Lightroom + Photoshop + Topaz plug-ins) and this is a program on which I’m focusing in this tutorial. However, many concepts and ideas can be used for other applications too. There is also Photomatix Essentials (formerly known as Photomatix Light) - now in version 3.2 - which is slightly easier to use for beginners yet it uses the same algorithms as the Pro version so you can achieve similar results with both applications.

TAKING A HDR PHOTO

CAMERA SETTINGS

I mentioned that today’s cameras aren’t capable of capturing real-life scene’s dynamic range so the question is how to take such a photo? We have to use a simple trick here. Instead of taking a single exposure we take 2, 3 or more each of them differently exposed (some darker, some brighter than “correct" exposure). Then this photos are merged into one in the “merge to HDR" process. The resulting photo has depth of 96 bits so it has much more data about scene luminosity than any of the source images. Number of photos required to cover dynamic range of a scene ranges from scene to scene. However, those photos should cover as much luminosity as possible from the brightest to the darkest parts of the frame. Sometimes it’s enough to take 1 photo (yes! Sometimes there is no need to bracket at all), sometimes 3 photos will do, sometimes, 5, 7 or even more. Of course number of photos depend on the EV spacing between the shots of the sequence but most popular steps are 1.0, 1.5, 2.0 EV.

Ok, so you might ask whether you should choose 1.0, 1.5 or 2.0 EV spacing? Generally speaking using 1 EV gives smoothest tonal gradations. But as stated above it requires twice as many shots as using 2 EV spacing - so the answer is - it depends. But to give you idea how this choice influences image quality head over to the section: Number of exposures and its influence on image quality.

Odd number of photo is used most frequently as this way we have equal number of photos for shadows and highlights and one more for “mid-tones". For 5 photos, this situation is depicted on the image below:

To get details in shadows it is necessary to use positive exposure compensations (eg. +2 EV, +4 EV) meaning that it is necessary to overexpose a photo. To get details in highlights it is necessary in turn to use negative compensation (eg. -2 EV, -4 EV) i.e. to take underexposed shot.

For most landscapes 3 photos are sufficient and then:

• 1 goes for mid-tones,
• 1 goes for correctly exposing the shadows (By this I mean that this photo will reveal details in shadows),
• 1 goes for correctly exposing the highlights.

The highest number of photos is required in case of very high contrast scenes like, eg.:

• Sunsets and sunrises,
• Forests with deep shadows and light shafts,
• Indoors especially dark ones when outdoors are also visible (through a window or doors),

It’s important to understand that “the more photos, the better" isn’t always true because:

• The more photos are taken, the longer it takes to shoot them all. It can lead to noticeable differences between the first and the last photo of the sequence caused by movement (wind, movement of people and vehicles) what can lead to artifacts known as ghosts.
• There might be no visual difference between 5 and 50 photos (if 5 photos are sufficient to cover all dynamic range of the scene; 50 won’t make it better). In this case it’s even possible that image quality will be degraded due to ghosting artifacts mentioned in the previous point. Besides the more photos, the more memory is required to process them and the more time it takes (50 photos would require a lot of memory – believe me :) ).
• When shooting hand-held it is very difficult to take more than 3 shots and have them properly aligned.

Taking right number of photos is very important as when there are too few photos then noise in the final shot can become more prominent.

As already mentioned these photos are then merged into HDR photo i.e. into a photo having much wider dynamic range than input images. In Photomatix and a number of other applications it’s all about loading all sequence and the merging process is fully automatic (although we still have opportunity of setting some options to influence it).

Although bracketed shots give best results in most cases (unless one photo covers whole dynamic range of the scene), Photomatix and other apps allow user to load and tone map a single photo. It doesn’t even need to be RAW. It can be both 16- and 8-bit TIFF or even JPEG file. The benefit of using a single exposure is that it allows us to shoot handheld and eliminates a problem of ghosts. Of course it won’t be a real HDR photo but the results are often still quite good. Below is example photo taken in Barcelona and tonemapped from a single file:

Most of the time I shoot 3 bracketed photos. This allows me to use auto-bracketing feature of
my DSLR which is a really neat feature (Unfortunately almost all Canon cameras can only shoot 3 photos in the auto-bracketing mode. It’s much better for owners of Nikon). Although auto-bracketing was invented for other purpose (namely increasing the chance of taking correctly exposed photo in difficult light situations) it works fantastic with HDR photography. I also use burst mode which slightly decreases time between shots in the sequence and is also very important in case of shooting handheld (I will tell more about it in a second).

Taking bracketed photos I start by finding the right exposure for the “middle" photo, i.e. the one I would use when I wouldn’t take HDR photo. It’s especially important when taking photo of very difficult scenes like beach or snow because to get good photo exposure biasing might be necessary to used. Then I take photos in a sequence using 2 EV step (sometimes 1.5 EV). Most of the time I use 3 bracketed photos (sometimes 5 or 7). It’s important to notice that bracketed photos have to be taken in one of 2 manual modes:

• Aperture Priority (Av, A),
• Fully manual (M).

Why? The answer is quite simple, we have to be able to change exposure between the consecutive shots of the sequence. However, we want to change exposure time only. Using aperture instead could result in some bad results due to large differences in depth of field. Changing ISO in turn could result in larger noise in some photos.

ISSUES

HDR photography is rather infamous for a few issues present in many photos. Thanks to them a lot of people assume that it each HDR photo have them. Below I just name the problems and give short description to each of them. You will find more comprehensive description on how to get rid of each of them in further parts of this tutorial (eg. when describing settings I use for Details Enhancer).

Noise

Concerning issues the first big one is noise. If we use local tone-mapping operators (like Details Enhancer for instance) it is essential to pay attention to this. As local tone-mapping operators enhance local details they will enhance noise at the same time (as there is no way to distinguish between noise and a very detailed texture). To prevent this do following:

• Cover dynamic range of the scene. If there will be enough information about shadows than noise won’t be prominent. It means that if the brightest photo in the scene doesn’'t lit shadows enough than noise from it will be transferred to the final image.
• Use low ISO values whenever possible. But it doesn’'t mean lowest values as in some
  cases ISO 50 or ISO 100 can have more noise than ISO 200. Check your camera lowest native
  ISO.

Misalignment

Next thing is vertical and horizontal movement between the shots of the bracketed sequence. This can cause issues with photo alignment. To minimize this movement it is good idea to use a sturdy tripod and to use remote shutter release (through a cable or pilot). However, many of my shots are taken hand-held at 10 mm (16 mm equivalent) or 24 mm and the movement is really hard to notice.

Oversaturated look

One of the common mistakes is that Saturation setting in Photomatix Pro is set to relatively high value. This makes colors to have this grunge or surreal look - they scream HDR! I usually don't go beyond 80 with this setting and most of the time I keep it around 40 or 50. Also you have to be aware that this slider is a bit different than Saturation in eg. Lightroom or Photoshop in a sense that other settings affect its behaviour, eg. using lower value for Strength allows you to use higher values for Saturation. Using higher values for Strength in turn requires reducing Saturation to keep the realistic look.
Another thing is that particular colors (especially reds and greens) might still look oversaturated despite using rather low Saturation value in Photomatix. The fix is easy. You can use Finishing Touch in Photomatix or Saturation sliders in Lightroom (or Hue/Saturation Adjustment Layer in Photoshop CS) to decrease saturation of these particular colors. Another fix is to use Vibrancy slider in Lightroom.
Here is example photo. The blues in the sky and reds of the tram are very unnatural in this case.

Halo artifacts

It's the most common mistake, made especially by beginners. It's about leaving halo artifacts around the edges. It's visible mostly on the boundary of two regions with very differencing brightness (eg. between sky and forest). You can fix this in many ways: decrease Strength, decrease Lighting Adjustments setting to Natural or Natural+, increase Smooth Highlights. You might also want to use combination of these to achieve halo-free results. Another fix is to use burn and dodge tools in Photoshop but I always try to fix it in Photomatix.
Here is example of this issue created when using Surreal preset from Photomatix Pro 4.2:

Ghosts

The last issue I would like to mention are ghosts. They are also caused by movement but contrary to problems with alignment ghosts are caused by the subject moving between shots: people can walk a few meters, the grass blades are waving, the water is flowing… the movement is everywhere! You just can’t say “hey world! Stop for a second". You would be ignored. I will tell a few more words on this matter when showing how to deal with them.

In the photo below you can see some ghosting artifacts: take a look especially at the car in the left of the image and people in the right. These are ghosts.

POST-PROCESSING WORK IN PHOTOMATIX PRO

At this stage you should more less understand what HDR really is and what we will try to achieve. So in this section I will show you how to use Photomatix Pro to load and process photos in it.

LOADING BRACKETED PHOTOS

After starting up Photomatix Pro the first step is to load our bracketed photos. We can do this by either:

1. Clicking on “Load Bracketed Photos" button in the left part of the screen,
2. Pressing CTRL + L (or using File -> Load Bracketed Photos… menu) or 
3. Dragging the photos to the Photomatix from Windows Explorer (or Adobe Bridge for instance).
4. If you own Adobe Lightroom you can also install a plugin which comes with Photomatix Pro. Then you will be able to export bracketed photos directly from Lightroom. Just select bracketed files in the library, right-click -> Export To -> Photomatix Pro.

A window will appear:

IMG_7379_HDR (1).CR2, IMG_7379_HDR (2).CR2 and IMG_7379_HDR (3).CR2 in the screenshot above are names of RAW photos from a -2; 0; +2 sequence taken by me. Also note “Show intermediary 32-bit HDR image". I have it checked almost all the time. This instructs Photomatix Pro to show you a merged HDR photo before actually tone-mapping it. One of the
benefits is that you can save this HDR photo and process it again whenever you want to (with different settings perhaps.). This saves a lot of time because merging to HDR can be a pretty time-consuming process (especially when using long sequences, large RAW files and using options as alignment and deghosting).

After clicking on the OK button another dialog is shown:

In this step we can decide how the photos will be merged into HDR photo. There are quite a lot of options here including alignment, deghosting and white balance:

• Align source images – this option enables alignment of photo which are misaligned (due to handshake or tripod shake):
• By correcting horizontal and vertical shifts – this option is much faster but it should be used only for the photos taken from a tripod.
• By matching features – this option is much slower yet it is very useful when photos were shot hand-held as it tries to match the features in the source photos.
• Remove ghosts – do you remember ghost artifacts I mentioned in the Issues section, well this option enables deghosting algorithm which removes artifacts caused by the subjects which moved across photos of the bracketed sequence. It is important to notice that this option should be disabled when there is no ghosting artifacts in the image as it can slightly degrade image quality (compare it to using Image Stabilization on a tripod).
• with Selective Deghosting tool – semi-automatical mode giving great control over ghost removal (described in the very next section)
• automatically – since version 4.1 this option can handle most of the ghosts without producing any artifacts. It is recommended to use when there are subjects like water, clouds or grass.
• Reduce noise – enables advanced noise reduction algorithm.
• Reduce chromatic aberrations – enables chromatic aberration reduction algorithm.
• White Balance – white balance (available only for the RAW photos).
• Color primaries based on – color space (available only for the RAW photos). You can choose from sRGB, Adobe RGB and ProPhoto.

SELECTIVE GHOST REMOVAL

If in the previous step „Remove ghosts with Selective Deghosting tool" was checked now you will be presented with tool to selectively remove ghosts.
Selective ghost removal in Photomatix Pro is about selecting ghosted region by drawing selection around it using lasso tool and then replacing this region with one of the source images.
After selecting with a lasso tool the region will be surrounded with dashed line:

Next right-click on the selected region and select "Mark selection as ghosted area" option as shown on the image below:

After marking the region as ghosted its border will become solid and option to select source photo to replace this ghosted region will become available after right-clicking this region.

At any time you can preview ghost removal by clicking on the Preview Deghosting button in the left side of the window.
Click Ok button to accept your changes and move to the next step.

MERGED HDR PHOTO

When „Show intermediary 32-bit HDR image" in „Load Bracketed Photos" dialog was checked Photomatix Pro will show it at this stage:

At this stage the photo doesn’t look quite good – it’s full of deep shadows and overexposed areas  at the same time. But this is HDR photo – your monitor cannot display it, however, so it shows only the part of the available exposure. You can use F11 key to decrease preview exposure and F12 to increase it. At this stage you can use File -> Save to save this intermediary image to .EXR or .HDR files. This is especially useful if you want to process your photos in some other application supporting this formats or want to go back to this photo later in Photomatix Pro (I do this often when I think that I will use several different settings on a given photo).

TONE-MAPPING STEP

So click on the „Tone Mapping / Fusion" button to move to the tone-mapping tool. Thanks to tone-mapping we can map our high dynamic range photo to limited capabilities of a monitor.
The graphical user interface of the tone-mapping step looks as shown below:

Below all the sections of GUI are briefly described:
1. Panel with choice of processing method.
Photomatix Pro offers several different methods of processing photos:

• Details Enhancer – local tone mapping operator,
• Tone Compressor – global tone mapping operator,
• Exposure Fusion – fusion of input photos. Exposure fusion is not tone mapping operator nor it produces HDR! Exposure fusion is technique of blending input photos by taking best pixels from each of them (based on some rank) and outputting it in the final result. Photomatix Pro 4.2 offers following exposure fusion algorithms:
• Natural (known as Adjust prior to version 4.2),
• Intensive,
• 2 Images,
• Auto,
• Average,
• Realistic - this method offers the most realistic results and was designed with Real Estate Photography in mind. However, as it is slower than any other method offered in Photomatix Pro, it is only available in the batch mode described later on.

Most of the time I use Details Enhancer, sometimes Tone Compressor (but only for portraits). I almost don’t use Exposure Fusion because I like a little painterly look which Details Enhancer produces. However, it is important to note that it is exposure fusion (especially Natural) that offers the most photo-realistic results. That’s why many pro real estate photographers use it exclusively.

Why do I use Tone Compressor for portraits? Because Details Enhancer enhances local details and contrast. So it enhances details also in the skin which is better to remain smooth. Otherwise the model looks as having serious skin diseases and the photo won’t be liked by him or her. However, Details Enhancer is very useful in enhancing eyes to add them some extra depth and magic. To do this multiple tone-mapping should be used which I will describe in a while.
2. Settings sliders and buttons allowing changing the look of the image. Number and type of the sliders depend on the selected processing metod. Details Enhancer have the largest number of them.
3. Process button. When you consider your image finished, click this button to process the photo and save it.
4. Contextual help displaying short text about slider over which mouse pointer is currently placed.If you're not sure what a given option is for, just move your mouse over it to see helfpul description.
5. Preview window – the preview window shows how the final image will look. Preview is already tone-mapped so it looks much better than HDR photo.
6. Histogram for the current settings.
7. Presets window. Photomatix Pro offers dozens of ready to use presets. Moreover, you can save your settings as a preset to use them later or download preset libraries from Internet.

As I already mentioned I use Details Enhancer almost exclusively because I like the artistic look it gives to my photos. As you might remember from the beginning of this article I use Photomatix to preserve details in highligts and shadows as much as possible. At this stage I'm not thinking about colours but rather light and detail. So here are the settings I use, together with short description of each of them:

• Basic options:
• Strength – controls degree of detail and contrast enhancements in the image. Most of the time I use values in the range of 50 - 70. Sometimes I may go beyond 70 but in such a case I lower other settings. Using very large values might result in halo artifacts appearing in the image.
• Color saturation – controls saturation and vibrance of colours. Most of the time I use 46, which is default value.
• Detail contrast – this setting is responsible for enhancing contrast in local details (extremely useful when there are some detailed textures in the picture). I usually use values ranging from 5 to 10 because I like to enhance contrast a little bit.
• Lighting Adjustments – one of the most important sliders in Photomatix Pro. It controls the general look of the image: natural vs. surreal. Using anything else than Natural+ (or Natural) might result in a very grungy and surreal look with a lot of halo artifacts.
• Additional options (More Options section):
• Smooth Highlights – this setting lets you smooth the highlights in the photo. It’s especially useful if you have large areas of blue sky in your shot which often contains a lot of noise. Also use it when you want to prevent white highlights from becoming grey. I use values in range 0 – 20.
• White Point – allows to set white point. Most of the time I lower it quite a lot to around 0.002% - 0.01%.
• Black Point – allows to set black point. Most of the time I don’t change it.
• Gamma – gamma… what to add here. In case of dark images I use values in range 0.8 – 0.9 and for bright photos I use 1.1 – 1.2.
• Temperature – colour temperature of the photo. Most of the time I don't change it at all (because I prefer to do this in post) but when I do I use values between 0.0 and 4.0. I don’t use higher values as I find them too warm. Values lower than 0.0 I use rarely even in case of snow and ice. For the photo below I used temperature of 1.5:

• Advanced options (Advanced Options section):
• Microsmoothing – is responsible for smoothing the enhancements done by local details enhancement. One of the effects is that it reduces noise (eg. in the sky). Most often I use default 2.0 value. When I have a lot of tiny details or grain (like snow or sand) I use much lower values like 0.5 – 1.0. For some grainy images I use values around 4 - 5.
• Saturation Highlights – controls saturation of highlights areas without affecting saturation of shadows. I often use default value. Sometimes positive (like 1.0).
• Saturation Shadows – controls saturation of shadows areas without affecting saturation of highlights. I often use default value. Sometimes negative (like eg. -1.0).
• Shadows Smoothness – reduces contrast enhancements in the shadows. The only setting I’ve never ever changed from its default value.
• Shadows Clipping – this setting is especially useful when dealing with noise in the shadows as it clips them. Most of the time I use default 0 value. Sometimes, however, I can increase it even to 20 or more if I have very noisy images.

ADDITIONAL POST-PROCESSING

Now we have ready to use tone-mapped photo. But as stated several times in this tutorial tone-mapping is just a beginning. During tone-mapping phase we wanted to preserver details in highlights and shadows. Now it's time to enhance colours and global contrast of the image.

If you do not own any photo editing application there is good news for you - since Photomatix Pro 4.2 it is possible to do basic fine tuning directly in Photomatix Pro. By default adjustments window appears after you click on the Process button but you can also open it by clicking on the Utilities -> Finishing Touch menu item. Following dialog will appear:

There are 3 types of adjustments you can make:

• Contrast (Contrast Tab),
• Color saturation  (Color Tab),
• Sharpening (Sharpening Tab).

They work similar to the tools with same names in Lightroom, Photoshop or GIMP so I will skip their description.

ADJUSTMENTS I MAKE

In this section I will describe typical adjustments I make to a photo processed in Photomatix.

1. I start my adjustments by importing a photo process in Photomatix and then I adjust following settings in Lightroom: 
1. Vibrance (I often decide to reduce it to to the value between -5 to -20),
2. Clarity (I often increase it to a value between 15 and 50),
3. Contrast (just a little bit at this stage),
4. Highlights and Shadows (to restore them).
5. If necessary I also correct colour balance at this step (especially greens as I have some problems capturing them properly or when I want warmer look for sunrises or sunsets). I often use presets at this step to make my work faster.
2. Export image to Photoshop... and now the real fun begins :) Yeah, I'm a great fan of Photoshop. I prefer to edit my photos in it and not in Lightroom. However, my editing in Photoshop is also quite simple... and yes I do use presets (Actions in this case) to make it even simpler :) :
1. I start with denoising my image using Topaz Denoise 5. I generally start by selecting a preset which removes all the noise and then select preset which is by a step weaker and make adjustments to it. Sometimes I apply different denoising to different parts of the image. 
2. After that I usually add some details using Topaz Detail 3 (new version really rocks!). This adds some clarity and visual sharpness to the image.
3. Next step is to play with colours. I use three tools for it:
1. Topaz Adjust - I use Topaz Adjust to make colours warmer and also to add some clarity and vibrance to the image.
2. Colour balance adjustment layer - I might use this tool when I want to give specific look to the image, eg. to make it more purple for sunrises. I usually make only subtle changes with it but enough to make the image nicer.
3. Hue/Saturation adjustment layer - I use it when some colours (eg. greens or blues) are oversaturated. I then reduce their saturation to make them look more naturally.
4. After that I might add a bit of contrast using Curves adjustment layer. Most of the time I use Linear Contrast preset.
4. Finally I apply sharpening. Most of the time I do it using Smart Sharpen or Unsharp Mask. However, recently I started to sharpen with High-pass filter and I'm pretty satisfied with the results. As I often do have sky in my photos I often sharpen selectively. Sometimes I create Layer Mask and paint on it manually with a very soft brush. Often, however, I generate it automatically by finding edges in the image and applying sharpening only to them.

Finally I save my image as a JPEG with a maximum quality. 

EXAMPLE

It is high time for an example of what I described so far. I will use one of my shots I took in Milan city some time ago:

Following source photos were used:

Here are EXIF data for these photos:
Camera: Canon 50D
Lens: Canon EF-S 10-22 mm f/3.5-f/4.5
Focal length: 10 mm
Aperture: f/5.6
ISO: 400
HDR: 3 photos shot hand-held in -2, 0, +2 sequence.
After selecting source photos I set preprocessing options in a following way:

As you probably noticed source photo include moving people so to remove ghosting artifacts I checked Semi-manual ghost removal option.
It is how I marked regions as ghosted:

As a source for the each of the ghosted regions I used 0 EV photo.

I used Details Enhancer tool with following settings:

• Strength - 100
• Color saturation - 70
•  Luminosity - 3.0
• Microcontrast - 7.0
• Smoothing - 1.0
• Gamma - 1.30
• Temperature - 2.0
• Saturation highlights - 3.0
• Saturation shadows - 0.0

All other settings were at their default values.

BLACK & WHITE HDR

Recently Black & White HDR photos are becoming quite popular. I also try to take some of them and here are some samples:

There are two ways to achieve this effect:

• Desaturate a photo in Photomatix Pro by setting Saturation slider to 0 and making sure that Saturation Highlights and Saturation Shadows is also set to 0.
• Converting the photo to grayscale in Photoshop or similar program.

It is possible to achieve striking results using any of these methods, however, I prefer to do this in post-production in Photoshop. Most of the time I use Topaz BW Effects to convert my images to black&white.

MULTIPLE TONE-MAPPING

After some time when one gets experienced in tone-mapping HDR photos it becomes clear that no matter what the settings are there are some scenes for which they simply don’t work – some areas look good with other settings, some look good with different ones, for instance:

• Eyes and cloth look better when using Details Enhancer but skin and hair look betterwhen using Tone Compressor.
• Water sometimes looks better at different settings than sky.

There is a simple solution. The HDR photo has to be processed several times with different settings (eg. with eyes looking good and with cloths looking good). Then those photos can be blended in Photoshop (or even in Photomatix) using layer masks.
There are even photographers who blend this way photos from different HDR software. Others blend input photos with the tone-mapped one (I use it occasionally). So there are many options.

EXPOSURE FUSION

INTRODUCTION

A long time ago when no one had heard about HDR, photographers were still able to increase the dynamic range of their photos. What they did, and many photographers still do, was to open several exposures in Photoshop and blend them using layer masks.  When they blended the layers they had to decide which image to use for each region of the image. This way they could restore highlights using an underexposed photo and details in shadows using an overexposed one.  Nowadays this technique is commonly referred to as manual blending or XDR for extended dynamic range (compared to high dynamic range).

Exposure Fusion is based on that experience but it is a more automatic process. Instead of doing it manually you can blend your images directly in Photomatix. Basically exposure fusion is about taking the best pixels from all photos and outputting them to the final image. Whether a pixel can be considered good or bad depends on many factors like for instance colour saturation, well-exposedeness, low noise-level etc. Also exposure fusion isn’t limited to simple read and write operations. For any pixel it can take data from 1 image or from all images and to calculate the mean of values read (or some other characteristic). It can also increase colour saturation and much more. The possibilities are virtually endless.

Unfortunately not many HDR software offer exposure fusion. Photomatix (both Pro and Essentials) and Enfuse are the most popular ones with such functionality built-in. I will focus on the first one in this tutorial.

Before jumping into details on processing using Exposure Fusion, here are some of the benefits of using it:

• exposure fusion results in noise reduction (contrary to local tone-mapping which amplifies noise) – this makes it perfect for night and long-exposure “HDR” photos,
• images have more natural look. Especially real-estate, night and foggy shots benefit from this natural look.
• images are free of halo artifacts,
• using exposure fusion might be easier because it has fewer parameters to set – also it is more intuitive as many photographers are already familiar with notion of blending images.

And here are drawbacks of it:

• images lack local contrast compared to tone-mapped images. However, this can be improved in post-processing,
• high memory usage that increases with bit-depth and number of images,
• works only with multiple exposures, if you need to use it for a single exposure you need to derive fake multiple exposures from it (eg. by adjusting Exposure slider in Lightroom and then exporting as TIFF/JPG). You can read how to this in my tutorial.

As you can see from above, exposure fusion produces images that doesn’t have problems typical for HDR photography: noise, halos and unnatural look. Sounds great, doesn’t it? Well, that’s one of the reasons exposure fusion became so popular amongst real estate photographers. That's also the reason why I use it for the majority of my night shots.

CREATING FUSED IMAGES IN PHOTOMATIX PRO

Creating fused images in Photomatix Pro doesn’t differ much from regular tone-mapping workflow. The main difference is step 1 below:
1) Make sure to use a dedicated RAW converter to convert images to JPG/TIFFs prior to loading them into Photomatix. This way you will achieve best quality. The reason for this is that the Raw converter built into Photomatix is quite simple – although sufficient for tone-mapping it doesn’t produce as good results when used together with exposure fusion. For this reason I always develop my images in Lightroom and then export them to Photomatix using the Lightroom plug-in (which comes with your copy of Photomatix Pro).
2) You start by selecting photos to fuse. As I already mentioned you need 2 or more photos to be able to use Exposure Fusion in Photomatix.
3) After clicking ok, you need to specify Preprocessing Options. I specified them this way and clicked Ok:

A few notes here. First of all if you’re using Lightroom, make full use of it. It has a powerful Raw converter so if you still remember point 1, it’s better to use it instead of Photomatix’s. Another benefit is that Photomatix integrates pretty well with Lightroom. If you haven’t already, make sure to install the Lightroom plug-in which comes with your copy of Photomatix. This way if you right click your images -> select Export -> Photomatix Pro you will be able to run Photomatix directly from Lightroom.
For this example I shot the photos with a tripod (7 exposures at 1 EV spacing). There could still be some small horizontal and vertical movement so I checked Align images by correcting horizontal and vertical shifts box. Also there were some people moving in the frame so I checked Remove ghosts option.
4) In Preview mode switch Process to Exposure Fusion:

5) Just below Process, there is a method combo-box. Select one of the following methods:

• Fusion/Natural – it produces the most natural-looking results (hence the name). I will focus on this method in this tutorial,
• Fusion/Intensive,
• Fusion/Auto – fuses images automatically, you can’t control the process at all,
• Fusion/Average – averages the images. Same as above – you have no influence on the look of the images,
• Fusion/2 images – let’s you select two images of all your exposures and then fuses only them,
• Fusion/Realistic – this option produces best results (at least for real estate photographers), however, it is also the most computationally-expensive one. For this reason it’s only available in batch mode

6) Specify parameters. For Fusion/Natural they are:

• Strength – strength of local contrast enhancements. I usually leave it at 0.0 or move it to the left (negative values) as it tends to produce more natural looking images
• Blending point - specifying negative value gives more weight to underexposed images; positive values give more weight to overexposed images in turn. If it sounds confusing – moving slider to the left makes Fusion algorithm “prefer” underexposed photos. Moving to the right, make it prefer overexposed ones.
• Shadows – brightens the shadows. I usually move this value to 10.0 which is maximum for this setting. This way I can restore more details in shadows.
• Local contrast – increases sharpness and local contrast of details in the image. I mentioned that Exposure Fusion does have worse local contrast than tone-mapping – this setting tries to overcome this. I try to keep this value in range 0.0 to 3.0. Larger values might result in a painterly and unnatural look. Value of 2.0 usually works best.
• Color saturation – increases or decreases saturation of colors in the image. I usually keep it at 0 as I play with colour later in Photoshop or Lightroom.
• White clip – clips the highlights. I usually don’t change it.
• Black clip – clips the shadows. I usually don’t change it.
• Midtone - specifies brightness of midtones. I usually move it to the right to the degree that depends stricly on the image

For my image I used settings from the image above.
7) Hit process button and save your image
At this stage your photo might look like this:

It looks natural, that’s for sure. However, it lacks contrast and colours a little bit (especially compared to tone-mapped images). So what I typically do at this stage is to open my photos in Lightroom or Photoshop and apply some adjustments there. Most of the time I increase contrast, colour saturation and sharpen my images. After that I end up with a photo like the one at the beginning of this article.

APPENDIX A: BATCH PROCESSING

Everything is fine and I hope clear up to now but how do you process HDR photos when you end up with a few hundreds to a few thousands of photos after a photo shoot? Opening each of them in Photomatix, making adjustments and then saving sounds like a tedious and very long task. Also it is rather difficult do choose the best image. When you have single images (i.e. not bracketed) you can compare them and choose one or few which you're going to process. But how to compare images when each of them is in fact built from 3, 5 or 7 photos? Should you compare underexposed images, normal exposure or maybe all images? This would complicate process of surveying very much. Another thing is doing timelapse.
Luckily, the solution to above problems is simple - use batch processing feature instead. Batch processing allows you  to process similar images all at once using same settings for all of them. Photomatix Pro has this feature built-in and as you will see in a minute it's quite powerful.

CHOOSING AND PREPARING PHOTOS

As mentioned above, all photos in the batch will be processed with the same settings, so you first need to select photos for processing. Generally I try to choose photos which are very similar to each other, have similar tones and light. Most of the time I create new folder in Lightroom (or Windows Explorer) and move all such photos to it. Then I take one bracketed sequence from this folder and open it in Photomatix Pro, choose preset and make adjustments to it, then I save it as a new preset which I will then use in batch processing. Why this is necessary? Batch processing doesn't allow you to preview your adjustments (this is same way as batch processing in Photoshop CS for instance).

I then close Preview mode with X button (there is no need to process a photo).

BATCH GUI

Now open Automate -> Batch Processing (or use CTRL + B shortcut). Following window will appear. It might look quite complex at first but it isn't.

Elements of the GUI are described below:

1. Top-left corner contains controls which allow you to choose method used for processing photos. You can select any method available in Photomatix Pro. There is even one more method - Fusion/Realistic. It's meant especially for real-estate photographers but it's significantly slower than any other method so it's not available in the interactive GUI mode. To process photos with a given method just check a box near the method name. If you choose more than one method (eg. both Details Enhancer and Tone Compressor) Photomatix will process each of your photos a few times saving you time to process photos several times separately. It's quite useful. Also note the "Settings..." button near each method name. Clicking it brings the dialog allowing you to select settings and preset. It looks very similarly to Settings Adjustments in the preview mode.
   Also note that in order to use Details Enhancer or Tone Compressor you need to check a box near "Merge into 32-bit HDR file". After clicking on the "Settings..." button next to this checkbox window similar to Preprocessing Options will appear allowing you to select eg. Ghost Removal settings, Chromatic aberration reduction, White balance settings etc.
2. Below methods section there is a section allowing you to choose number of exposures. If you used sequences with 3 bracketed shots choose 3. If 5, select 5. But what if you used sequences with both 3, 5 and 7 images? It's still possible. Click on the Advanced button and choose "Automatically detect number of bracketed frames" option.
3. Then there is a section with alignment settings. All settings are similar to settings from Preprocessing window so I will skip their description.
4. Underneath there is a source files section. If you want to process whole folder choose "Selection by folder" and then click on the "Select folder" button and navigate to your folder. If you, however, prefer to process only a few files, select "Selection by individual files" and then click on the "Select files" button and in the opened window select files you want to process. There is also a list of files. Clicking on any file in it will show small preview of it to the right. There is also option to remove file and filter files by type.
   If you want to process photos in subfolders be sure to check "Process subfolders" checkbox as otherwise those photos won't be processed.
5. In the top right part of the form there are 3 buttons:
1. Run - starts the batch,
2. Close - close the batch window,
3. Stop - cancels the batch processing. Note that this button appears only after clicking on the Run button.
6. Below there is large text section - it's a batch log. Generally speaking all messages will appear here. Most of them will be information but also errors will appear here. Errors might appear when Photomatix could not process images for some reason (eg. when it couldn't find bracketed sequences). In the screenshot above I cancelled the batch processing by clicking on the Stop button, hence the message.
7. In the bottom right corner you have settings to specify your output settings. First you have to specify output directory and you have two options here:
1. Created under Source Folder - this is default option. Photomatix Pro will create new folder in your source directory and save the output images there. The folder will have name in form PhotomatixResultsXX where XX is a number. For instance if there is already PhotomatixResults01, Photomatix will save result files under PhotomatixResults02.
2. Customized location - choose this option when you want to save your images to destination of your choice.

Then you can select format of the saved image (JPEG, 8- and 16-bit TIFF files) and in case of JPEGs specify quality (in the range 0 to 100).

Moreover, you can select format of 32-bit HDR image generating when "Merge into 32-bit HDR file" is checked. You can select radiance (HDR) and EXR formats. There is also a checkbox "Remove 32-bit HDR file after tone mapping". If you want to use HDR image for other purpose (eg. to tone map it again later without need of merging again), uncheck this option.

In this section there is also a Naming & Output Options button. Clicking it brings another window:

This form allows you to choose naming scheme, Append custom suffix to the output files (eg. I use "_HDR" suffix). Resizing section allows you to choose output size of the images. By checking "Resize output to" box and typing width and height you can shrink the output images. Finishing section in turn allows you to apply finishing touch to all output images. You can apply contrast and sharpening enhancements.

RUNNING BATCH

This is very simple, just:

1. Set settings as desired
2. Click Run button
3. Wait (or eat a dinner or in case you have thousands of shots to process - go for a walk). It's slow process 

APPENDIX B: GUI TIPS & TRICKS

Regarding tone mapping or fusion settings:

• Double clicking on the setting slider resets it to its defaults.
• You can click on a value next to the slider to edit it by typing it - useful when you know exactly what to put there.
• Using mouse wheel on the settings window will scroll it horizontally.
• With CTRL key pressed when mouse pointer is over a slider you can use mouse wheel to control the value. It's very useful if you want to move it just slightly as this method permits for very small value changes (like 1 or 2 increments - what I mean is it's very precise).
• Using mouse wheel on the presets window will scroll it (horizontally or vertically depending on its orientation).
• When a preset is selected (marked by a white border in the presets window) you can move to the previous preset by using Up or Left arrow keys. To move to the next one you can use Down or Right arrow keys. This way you can quickly go through available presets to compare the results

Regarding image (all types of previews and final image):

• Using mouse wheel on the image will scroll it horizontally (when horizontal scrollbar is visible). You can also use mouse wheel on the image scrollbars to scroll horizontally or vertically.
• Using mouse wheel on the image while CTRL key is pressed will zoom it

Other:

• You can also use a number of shortcuts like CTRL+O to open file or CTRL+L to load bracketed set - make sure to study menu items (as shortcuts are listed right to them).
• You can set orientation of the presets window in preferences. Just open Preferences - General Tab -> Orientation of Preset Thumbnails. I always have it in vertical orientation.

APPENDIX C: NUMBER OF EXPOSURES AND ITS INFLUENCE ON IMAGE QUALITY

Most tutorials about HDR photography recommend taking 3 photos with 1.5 or 2 EV spacing in most situations to cover whole dynamic range of the scene. Although it is true in the majority of cases, there are scenes when 3 photos with even 2 EV spacing won't cover whole dynamic range of the scene.

In this section I will try to show differences in the final image look based on the number of exposures taken: 3, 5 and 7. All photos were tone-mapped in Photomatix Pro 4.2.3 using the same settings. No further editing was done on any of them. Also I used different EV spacing on some of the shots to give you an idea how it affects image quality.

Move your mouse pointer over any of the images to see previous one in the sequence. This will make it easier to compare images.

Here is a photo tone-mapped from only 3 exposures at 1.5 EV spacing:

Note how much detail is lost in this shot both in shadows and highlights. The sky is faded out (and the sun is almost completely blown out) and the forest lacks contrast. It is a sign that whole dynamic range of the scene wasn't covered.

So now let's try with 3 photos taken at 3 EV spacing (there are some cameras, not many, which allow to do this):

Move your mouse over to compare with previous photo

Much better (there is some blue in the sky, the sun doesn't seem to be completely blown out and we have some contrast in the forest too). However, the tonal gradations aren't smooth really. Look at the clouds in the left for instance - they are pretty much one colour making the clouds look rather flat and boring.

So to fix this we instead take 5 exposures at 1.5 EV spacing, this would ensure smoother tonal gradations:

Move your mouse over to compare with previous photo

Now it starts to look good :) Note how clouds look more 3-dimensional now due to some extra tonal gradations.

Finally let's try with 7 exposures at 1.5 EV spacing:

Move your mouse over to compare with previous photo

In this case the difference is rather subtle. There is a bit more detail in the clouds and also some of the highlights around the sun were restored. Although the difference seems to be insignificant it really matters when this image is viewed in large size.

APPENDIX D: DEALING WITH HALO ARTIFACTS

Halo artifacts. One of the nightmares in HDR photography. They appear between regions of different luminosity and virtually ruin any photo. You might have great composition, light and colours but if you have halos in your photo - it won't be considered good - rather poorly executed.

It might be that even when you followed all my steps above and used low settings for Strength there are still some ugly halo artifacts. They can appear especially in the sunrise/sunset scenes and after using some Photoshop filters (like eg. Topaz or even Curves adjustments layer).

What you will need is Photoshop. First open your image with halo artifacts:

At full size it doesn't look very bad but hit CTRL + MINUS keys several times to see nasty halo artifacts. Ugh...

As you see highlights in the sky are a way too strong and also shadows are a way too deep. So the easiest thing to do would be to adjust both by using Curves adjustments layer.

First make sure to select sky only (eg. with Wand selection tool) as the halos are present only in it. Then add Curves adjustment layer.

For this image I used following settings:

Note I darkened highlights and brightened shadows a little bit. After that adjustment the image looks like this:

It's slightly better but still far from good.

So what we will do is to manually Dodge & Burn the sky to get rid of too dark regions and too bright ones too. Fear not - this tool is very easy to do (and powerful too!) but I admit one has to get used to using it.

You can use Dodge and Burn tools from the Photoshop toolbox for this but they have one serious disadvantage - they both are destructive tools. I prefer editing my images in a non-destructive way so I do the following:

1. Press CTRL + SHIFT + N to create a new layer. In a dialog box that appears, change Mode to Soft Light and also check the box at the bottom to fill the new layer with neutral grey colour.
2. Press Ok, to create the layer.
3. With your new layer selected select Brush tool and change its Flow to around 2 - 3%. Also make sure your brush is soft.
4. Paint over dark regions with White colour and over bright ones with Black. Using White colour has effect of brightening the image, while using Black - of darkening it. So when you use White on Shadows you brighten them up. Similarly when you use Black on Highlights you darken them.
5. While painting make sure to zoom out from time to time because it might be easier to see halos at smaller magnification.

Here is the final result:

Although still not perfect, it now does look a lot better :)

For your reference, here is also the Dodge & Burn layer I used. Note that the brightest parts of the image were painted with black and darkest with white colour.