If you are looking for a good way combine multiple exposures to achieve dynamic range in a natural or realistic maner, you should give the exposure fusion method a try. Although you can achieve realistic looking images using the tone mapping options, exposure fusion will give very good results with a lot less work on your part. The exception is that if you have moving objects in your scene, you might want to use the tone mapping option to take advantage of the deghosting feature. Additionally, for really high dynamic range images, tone mapping will be the better option as exposure fusion doesn’t handle really high dynamic range very well – i.e. it won’t look natural.
The first options you have within exposure fusion allows you to select how the exposure fusion should work or which method you want to use. There are five options.
Average will average the exposures together based on the available information in the exposures. You do not have any options available to you with this method and I find it rare that you would ever want to use it. After all, when would you want a straight average of anything?
Highlights & Shadows – Auto looks at the highlights and shadow information in each of the exposures and blends these exposures together to achieve a natural and realistic look. Again, there are no adjustments that you can make with this method. Although the results look pretty good, I would rather have some control over the outcome rather than letting the computer decide what the final image should look like. So again, it is rare that I would use this method.
Highlights & Shadows – 2 Images allows you to select which two images of your set to use then applies the “auto” method to blend these images together for the final result. There are no adjustments available other than selecting which two images to use. This method may get you the result you’re looking for, but if you want to tweak your image, this is not the method to use.
Highlights & Shadows – Intensive applies a rather aggressive blending or fusing method that often causes banding or an unnatural look in clouds. Luckily, this option gives us three sliders for some control of the final look. Of the three sliders, Radius has the most effect on the image because it sets the weighting amount to use when fusing the images together. The higher the number the less banding and haloing you will see, but it takes significantly longer to process the image. If you use this method, and you should try it, adjust the radius first to dail in the overall look of your image, then adjust the local contrast using the Strength slider. Negative numbers on the strength slider will flatten your image by removing contrast and positive numbers will punch up the contrast and increase depth. Lastly adjust Color Saturation to your desired amount. Just remember, too much of a good thing is not good – make small adjustments and maybe don’t adjust the color at all within photomatix. Save the color adjustments for photoshop, lightroom, or other photo editing software used in your post processing work flow.
Highlights & Shadows – Adjust applies the same blending or fusing of the auto method, but allows you to make a number of adjustments to the final image. This is the default method for exposure fusion and is the method you will end up using for more than 90% of your images for which you use exposure fusion.
At left you see the adjustment panel for the adjust method. I will go through each of these controls in the order in which you should use them (which is not the order – top to bottom – they are presented). Although I am suggesting a certain order for using these controls which I hope will make sense, you can use them in any order you choose. So let’s get started.
Blending Point – this controls the weighting given to the under exposed images versus the over exposed images. If you want the fusion to use more information from the underexposed images, move this slider to the left or into the negative numbers. Likewise, move the slider to the right or into the positive numbers if you want to include more information from the over exposed images. Another way to think of this control is to think of it as an exposure control – negative numbers will under expose where positive numbers will over expose your image.
Accentuation – this is the same as the Strength slider in the intensive method. It controls local contrast. Moving the slider to the left into negative numbers will remove contrast and flatten the look of your image. Moving the slider to the right into the positive numbers will punch up the contrast and increase depth.
Shadows – this controls the brightness of the shadow areas without affecting the highlights. If the shadow areas in your image are too dark, move this slider to the right to brighten up the shadows. Again, remember a little adjustment goes a long ways. Don’t over do it.
White Clip – Think of this as a fine tune adjustment for contrast in the highlight regions of your image. Increasing this slider – moving it to the right – will increase contrast in the image but does it at the expense of detail in the highlights. You will lose detail in the highlight regions when increasing the white clip slider.
Black Clip – works the same way as the white clip, just does it’s work in the shadow regions of your image. Increasing this slider – moving it to the right – will increase contrast in the image at the expense of detail in the shadow regions, i.e. you will lose detail in the shadows when increasing this slider.
Midtone – controls the overall brightness of the image but also affects contrast. Moving the slider to the left reduces brightness in the image and increases contrast. Moving the slider to the right will brighten the image but reduce overall contrast. To dial in just the right look may require multiple adjustments to Accentuation, White & Black Clip, and Midtone sliders. Just make small adjustments as you dial in the right look.
Color Saturation – does just what the name suggests, it adjusts the saturation of the color in the image. This is a global control and as such you may want to consider making color adjustments in photoshop, lightroom, or other photo editing software that is designed specifically to work with color. I have at times increased this slider to add just a little more color to my image, but I will always fine tune the color in other photo editing software.
360 degree image – removes the seam from a 360 degree panorama. This is another option that is probably better left to another application that is designed specifically for processing panoramas.
Presets – allows you to select and/or save presets for use. If you have dialed in a specific look that you like, save it as a preset. Then on the next image all you need to do is select your preset and your done!
Again, remember that when you click on the process button, you are not done. Your image is now at that RAW stage and additional post processing is needed to finish up and give the image it’s final look.
That’s all! Hope you find this reference of use.
