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Tone Mapping in Photomatix – A Reference

July 24, 2010 / Bruce posted in Photomatix, Tutorial / 3 Comments

Tone mapping using the details enhancer in Photomatix Pro 3 can be a confusing prospect. How are you supposed to know what settings to use on each of the many controls? This was a question I asked many times when I started using Photomatix. Refering to the manual gave me some indication of what the controls did, but I was still left without any idea how or when I should use them.

After much experimentation and reviewing multiple sources of information on the subject, I have come up with what I believe will be a helpful reference. A reference that should be a big help to those just starting out in the world of HDRI photography, and a good refesher for everyone else.

Photomatix Tone Mapping

So lets get started. The image to the left shows the details enhancer controls in the tone mapping option of Photomatix. You will notice that the color settings section is not expanded. The reason for this is simple – making changes to the color of an image is better done in Photoshop, Lightroom, or other image editing software specifically designed for this purpose. Therefore, we will not cover the color settings here.

At the top of the details enhancer controls are five sliders that will control the overall look of your image. Let’s look at each of these controls in the order of impact (could also think of this as the order to apply these controls).

Smoothing – This controls the transitions between the edges in your image. So what does that mean? It means that the more you increase this setting (move the slider to the right) the sharper the definition of the edges in your image. Another way to think of this – the higher the number, the more photo realistic your image. The lower the number (moving the slider to the left), the more painterly or grungy your image will look.

Strength – This controls how strong the overall contrast enhancement effect will be. If you are familiar with Photoshop, think of this as opacity. The higher the number (slider to the right), the stronger the effect. You may end up adjusting this slider multiple times as you dial in the look you want for your image.

Luminosity – This controls how bright the shadow areas of your image will be. The higher the number the lighter the shadows, and the lower the number the darker the shadows. For a more photo realistic image move this slider to the left. This control along with Smoothing and Highlight Smoothing is what you will use to control “halos” in your image. Halos are areas of light around edges and are typically found in the transitions between buildings and the sky. Adjusting the strength may also be necessary if you wish to remove the halos compeletly.

Microcontrast – This controls how exagerated the fine details are in the image. The higher the number, the more exagerated the fine detail becomes, and the lower the number the less exagerated the fine details. For a photo realistic image, this slider should be kept towards the middle range and will depend on the image.

Color Saturation – This control does pretty much what the name suggests – it controls the intensity of the color and affects all colors in the image equally. Warning, it is very easy to over do it with this control. Make small adjustments only, or leave as is and do all color adjusting in Photoshop, Lightroom, or other editing software.

After adjusting these five controls you will have dialed in about 90% of the overall look of your image, and in some cases, no additional adjustment in Photomatix is needed. However, there will be some images that will need additional fine tunning. That is what the remainder of the controls are for. We go through these from top to bottom starting with the White Point adjustment in Tone Settings.

Note of Particular interest: if the control in Photomatix has “smoothing” in the name of the control, then the higher you adjust this control the more photo realistic your image will become. The lower the number the more illustrative the look. However, like with all things good, you can over do it so make small adjustments.

White Point – This controls how bright the brightest point in the image will be. As you adjust this, watch the effect on the histogram. You should see the histogram move to the right as you adjust this control to a higher number. Adjusting too far will cause clipping (a loss of detail) in the highlights.

Black Point – This controls how dark the darkest point in the image will be. Again, as you adjust this, watch the effect on the histogram. You should see the histogram move to the left as you adjust this control to a higher number. Adjusting too far will cause clipping (a loss of detail) in the shadows.

Gamma – This controls the overall brightness of the image. Moving the slider to the left (to a higher number) darkens the image, and moving the slider to the right (to a lower number) lightens the image. After making an adjustment to the Gamma, you might need to go back and adjust the Strength slider.

Now we move into the Miscellaneous Settings.

Micro-Smoothing – This control smoothes out local detail enhancements and tends to reduce noise giving your image a cleaner look. The higher the number the stronger this effect.

Highlights Smoothing – This control determines how much to reduce the contrast enhancements in the highlight areas of the image. The higher the number the larger the area of highlights are affected. This control also has the effect of preventing white areas from turning grey and for light blue areas from turning dark blue or grey. This control also helps to reduce the halo effect where bright areas come in contact with darker objects.

Shadows Smoothing – This control reduces contrast enhancements in the shadow areas and will help to reduce noise in the darker regions of your image.

Shadows Clipping – Can you guess what this control does? I’ll bet you can – it controls the amount of clipping in the shadow regions of your image. The higher the number, the more shadow detail is clipped. This can be useful in reducing noise in these areas, but it comes at the cost of detail – so use sparingly.

That’s it! At this point you have merged multiple images together and mapped them to the point of a RAW image straight out of the camera. What do I mean by this? Simple, once you have made all your adjustments in Photomatix, you are now at a starting point of post processing your image in the same manner as you would with a single image straight out of the camera. You should not make the mistake of thinking you are done when you save the image in Photomatix, because you are not. You are just beginning.

Hope you find this as useful as I do. I refer to my cheat sheet everytime I begin a tone mapping process. Oh, one other thing. Determine what type of look you want for your image, then select a preset that gets you close to that look. Then go through the controls and dial in the look you really want. This is the easiest and fastest way to tone map an image.

Have fun!

The HDR “Look”?

July 15, 2010 / Bruce posted in Thoughts / 11 Comments

Ok, I recently entered an HDR image of mine into a competition. One of the judges comments was “…it doesn’t look like and HDR image.” Am I missing something here? I want to take this as a complement, but it just doesn’t feel like one!

I thought HDR was a technique not a look. Sure, HDR allows for the creative and artistic expression which can be taken to the extreme, but that isn’t what HDR is all about – is it? In my mind, if I’m able to combine multiple exposures into an HDR image that looks like a regular photo, then I have acheived what HDR was developed to do. It is a technique that allows photographers to capture a scene as close to what they see with their eyes, and recreate it photographically.

I think it is a shame that people have come to expect HDR photography to have a certain “look”. This look they have come to associate with HDR photography has come from the creative and artistic expression that HDR technique allows photographers to use in the creation of their art. It is ill advised for judges of photography to expect “ALL” HDR images to have the more creative or surreal look with accentuated detail and deeply saturated colors. If this is what judges of photography expect of HDR, then they need to be seriously re-educated before they pass judgement!

I don’t have anything against the creative and artistic looks that can be acheived through the HDR technique. Some of these images are beautiful expressions of art. What I do have a problem with is labeling a technique as a “look”, and the blanket inclusion of all images created by this technique being required to have the “look”.

That is my thought on the matter – what are your thoughts?

Creating an HDR Image

July 8, 2010 / Bruce posted in Lightroom, Photomatix, Tutorial / 3 Comments

If you are like most photographers, creating an HDR image is like stepping off the edge in the world of the unknown. Taking the plunge doesn’t have to be scarry though, and in reality it can be a lot of fun!

In this article, I’ll take you through the steps to create an HDR image simply. By this I mean that I will keep the process simple and easy. So let’s take a look at the steps involved, and then discuss each of these steps.

1. Take a series of bracketed images of the same scene
2. Merge the series of bracketed images into an HDR image
3. Tone map the HDR image
4. Do normal post processing on the resultant tone mapped image

There they are, all the steps needed to create an HDR image in the simplest way possible. So let’s get started, but before we do maybe we should revisit or explain what HDR is. HDR stands for High Dynamic Range which simply means more tonal range that what your camera can capture in a single image. Camera’s today do a really good job of capturing tonal range, but they are limited in what they can do. Your eye can see about 12 stops of light, yet the best DSLR’s on the market today can only capture about 6-8 stops of light in a single capture. This is one reason why your pictures are disappointing and don’t look like what you saw. It’s not your fault, it’s the camera’s fault. It just can’t see what you see.

So if the camera can’t see what I see, then how do I capture the image I’m seeing? This is where HDR imaging comes to the rescue. With HDR Imaging, you will take multiple images of the same scene at different exposures, generally at -2ev, 0ev, +2ev. Canon cameras allow you to set these bracketing steps in camera, however, Nikon cameras only bracket in up to 1ev steps. So on a Nikon camera, you would bracket to take five exposures at -2ev, -1ev, 0ev, +1ev, +2ev. I’m not familiar with the other camera makes, so for you Sony, Pentax, or other camera makes you will need to refer to your users manual to learn how to set up bracketing. Anyway, taking a series of backeted images like this allows you to extend the dynamic range of the camera by four stops of light (two stops under, and two stops over the normal exposure range). So now instead of six stops of light with a single exposure, we have 10 stops of light through our bracketed exposures. If you wanted to extend the range to 12 stops of light, on the Nikon you would dial in seven bracketed exposures. The Canon cameras require some manual intervention though because they only bracket three exposures. How to do this on a Canon is beyond the scope of this article (I’m a Nikon shooter). The Nikon cameras can bracket up to nine images at 1ev stop intervals, more if less than 1ev intervals. Any way, I digress…

Step 1. Take a series of bracketed images of the same scene

To do this, you will need to set your camera up appropriately. There are two modes that work, aperture priority and manual. I recommend using manual mode, but this is a personal preference as either mode will work. You will need to set your base exposure (the 0ev exposure) as you would for any normal scene using which ever metering method you prefer. I prefer spot metering as I feel it gives me more control over the exposure. Then set your camera to bracket for the number of exposures you need to capture all the detail.

Pearl Lake - 0ev

Pearl Lake - -2ev

Pearl Lake - -1ev

Pearl Lake - +1ev

Pearl Lake - +2ev

There are a number of ways to determine how many exposures you will need. One of the best ways is to use spot metering and meter the darkest area you want to retain detail, then meter the lightest area you want to retain detail in and calculate the difference between. If the difference was nine stops, then setting the camera for two over and two under will capture the entire range of the scene if your camera normally captures 6-8 stops of light. Just don’t forget to set the camera for the middle exposure or you won’t get the full dynamic range of the scene.

Before you press the shutter and capture those bracketed images, mount your camera on a tripod and use the cable shutter release. Doing so will ensure you get good sharpness throughout in your images. If you don’t have a tripod handy, set your camera to shoot continuous high speed and steady yourself as best you can. Take a deep breath in, then let the breath out slowly, then press the shutter to capture the bracketed images.

For this article, I shot five frames (bracketed images) on my Nikon handheld as seen here. I didn’t have my tripod handy when I came upon the scene.

As you can see, these images are nothing special to look at in this stage of the process. They are straight out of the camera – raw. That’s another thing I forgot to mention above, when shooting to do an HDR, always shoot in camera raw. Doing so will ensure you have all the detail to work with in the later stages of the process. Before anyone has a problem with this, yes, it can be done with a jpeg file, but you will get significantly better results with a raw image.

Now after I have captured the images, I will load them into Lightroom to organize, catalog, etc… From Lightroom I will select the five images and export them to Photomatix. There are a lot of HDR software applications out there and most will do the job really well. However, what I found after doing a lot of research is there is one application that stands out and is used by more professional photographers than any other HDR software application available. The HDR software application of choice by these pros was Photomatix. This is the application I use, and after comparing the results with several others, it has quickly become my HDR software application of choice. Besides, it integrates with Lightroom very well and makes my work flow smoother. So now it’s on to step two of the process.

Step 2. Merge the series of bracketed images into an HDR image

As soon as I select export to Photomatix, I’m presented with the following options:

When this dialog box opens, there are some default options already selected. Since we are creating an HDR image, the Generate HDR Image option is selected. It’s a good idea to make sure that the options to reduce chromatic aberations and to reduce noise are selected. Sometimes during the merge to HDR process additional noise finds it’s way into the image as do some aberations. With these two options selected, Photomatix will attempt to reduce both, and you will get better results.

The option to reduce ghosting artifacts is not selected by default. If you have any moving objects caused by wind, people, cars, etc… it’s a good idea to select this option. This option also has two sub-options. One for background movements, the the other for moving objects or people. I always select the option for moving objects or people. I’m not really sure why the background movements option is there or even what it does. I’m sure there is a reason, I just don’t know what it is and have not found a situation where I thought I might need this option. The next option tells Photomatix to go straight to Tone Mapping after generating the HDR. I will generally do this except in some instances where I might want to play around with different settings in Photomatix creating multiple HDR files of which I can blend together in Photoshop for some really cool looks. However, since most of what I do is to generate the most realistic and natural look, I will leave this option selected and let Photomatix go directly into tone mapping after generating the HDR file.

The next option is for alignment of the bracketed images. My suggestion, always, always, always select this option even if you used a tripod. The end result will be much better if you allow Photomatix to align the images. Here again there are two options, select the option that fits best with the type of images you are asking Photomatix to align. For the types of images I do, I have found that the option for matching features gives me the best result.

The other options deal with file naming and how the file should be reimported into Lightroom when the HDR file is created. Always select 16 bit tiff for your file size option as this will maximize the detail that is created.

A note on the stacking option. I used this when I first started using Photomatix and quickly got frustrated. It is not a fault of Photomatix, it is a Lightroom option which will stack the created HDR image with the first image in the bracketed series. For some this might work, for me, I found it to be an exercise in frustration trying to get back to the HDR image I just created. I know it is just me, so experiement with this setting. If you don’t select it, the HDR image is reimported and displayed in Lightroom as the image before the first image in the series. Ok, I know, it’s just me and I don’t work well with the stacking option in Lightroom. It just doesn’t fit into my work flow.

Once the options are set, I click on Export and let Lightroom export the selected images as tiff files to Photomatix. Once Photomatix opens, it will automatically load the tiff images and generate the HDR image. If I left the option selected to go straight to tone mapping my HDR image will open up in the tone mapping screen, which takes us to the next step. See this isn’t that hard, is it?

Step 3. Tone map the HDR image

In this step we have a lot of options available to us, and the number of options and sliders can be overwhelming. However, the good folks at HDRSoft have provided some presets to help us out.

You can see at this stage the image is nothing spectacular. In fact it looks rather washed out and not a lot of contrast. That’s ok though, we’ll fix that later. What we need to do at this stage is to make sure the tone mapping is able to compress the vast amount of information available in the HDR file down to a manageable file that can be displayed on the screen and printed.

Since I want this image to look natural and realistic, the first thing I will do is select the natural preset from the list of presets. The result of this selection is what you see in the example image. The only other thing I will do here is to adjust the strength slider up to around 70 which gives a richer, deeper look to the tone mapped image. When you’re at this stage with your image, I suggest you move each slider and watch what it does. This seems to be the best way to learn what the sliders do. The main sliders I work with in the tone mapping screen are the strength, Microcontrast, and Smoothing. Sometimes I will adjust the Luminosity when I’m seeing the halo effect, but most of the time I will just click on the natural preset then adjust the strength slider to my liking.

Even though you can create a fully finished product in Photomatix, I have found it easier to let Photomatix do what it is really good at – which is merging multiple images into an HDR file, and let Lightroom or Photoshop do what it is really good at – which is adjusting color and editing. So again, for most of my images (and the one shown in this article), I will select the natural preset, increase the strength to my liking, and click Save and Re-import to finish up the editing process in Lightroom and/or Photoshop. For more details on tone mapping in Photomatix, watch the tutorial and refer to the HDRSoft support and documentation. Additionally there are literally hundreds of articles and documents on how to use Photomatix. Do a search on Google and you will find plenty to read.

Step 4. Do normal post processing on the resultant tone mapped image

Once I have the tone mapped image back into Lightroom (and it doesn’t look all that good yet), I will start to apply a standard set of adjustments which will have a dramatic effect on the image. The first is to adjust the exposure. This is only needed if the right edge of the histogram is not touching the border of the histogram box, and this is image dependent. You may not want to adjust the exposure. The second adjustment is that of black clipping, this will cause the left side of the histogram to come in contact with the border of the histogram box. This adjustment is almost always needed, and when you make this adjustment you can watch the washed out look give way to a rich and colorful image. These two adjustments in Lightroom are the same as doing a Levels adjustment in Photoshop.

The next adjustment is to add in some vibrance and clarity, then do a tone curve to increase contrast just a little. After that, what adjustments you make are pretty much a matter of taste, but up this point, this is all you need to do to create an HDR image in as simple a way as possible.

For my example image, I cropped it a bit to raise the horizon line to the third line, added a gradient to both the top and bottom of the image to enhance the color, then dodged areas in the trees where the gradient made it too dark. This last step was done in Photoshop. The resultant image looks like this:

Pearl Lake

That’s all there is to it! Hope you enjoyed this article.

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Update: The good folks at HDRSoft have provided a coupon code for readers of this site to receive 15% off on their purchase of Photomatix. Just enter the coupon code “HDRPhotoZone” in the coupon box at checkout! Many thanks to HDRSoft!

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