HDR Tutorial 2: Producing HDR image and Tonemapping with Photomatix

 

Photomatix is where the magic happens and you’ll get to see the HDR image coming together. I guess the first step is to download it, if you haven’t already. You can download the trial version by following this link. Once you’re ready to buy, you can use the coupon code “TraverseEarth” for a 15% discount.

Once you’ve got Photomatix, it’s time to get started. I like to open Photomatix, select the images I’ll be working with in Adobe Bridge and then drag them into Photomatix. At this point the following dialog box will appear. You just need to ensure that “Merge for HDR Processing” is selected and then click the OK button.

Following this, the next box to pop up is the one below. If you’d used the alternative route to open your files, by clicking File>Load Bracketed Photos this is where you’d select the photos to process. As you’ve already dragged your images over, you can just click OK.

 

The following dialog box is the result of aligning the images in Photoshop. As they were combined into one document they will have lost the exif data indicating which exposure is which. Photomatix is quite smart in that it always successfully arranges the images from light to dark. However, it typically gets the Exposure Values wrong.

This is an easy fix. You can simply click the drop down box next to Specify the E.V. spacing. In this case I know that the photos were spaced 2 stops apart. So, as you can see below, I selected 2 in this drop down menu and Photomatix adjusted the values correctly.

That step ends the bits that we can fly through without thinking. The next step requires our input. The “Preprocessing Options” dialog box is the next one to pop up. I’ll go through what each of these is below.

Pre-processing Options Explained:

  1. Align source images: As we aligned the source images in Photoshop we don’t need to check the box here. As I mentioned before, Photomatix does a good job of aligning the images but it’s easier to get your source images aligned in Photoshop. This allows you to align all the different images with the HDR image for fine tuning. If you align the images in Photoshop you’ve got the tricky job of aligning the tone-mapped images with the source images.
  2. Remove Ghosts: This is an important part of the HDR process. Ghosting results from motion in the scene. Anything moving through the frame is captured differently between each exposure. The end result is that you end up with weird ghostly looking multiple images in your final result. One way to deal with this is to mask in one of the original photos. I prefer to try to deal with ghosting as much as possible with Photomatix. If you can do it here it makes life much easier. In the photo we’re working on, we have people moving about as well as waves washing up on the beach, so as you can see above I’ve selected “Remove Ghosts”. You can choose to let Photomatix do this automatically but it tends to work out better if you use the ”Selective Deghosting” tool.
  3. Reduce noise on: Photomatix has noise reduction capabilities. However, as noted above I prefer to use Noiseware Pro. It’s a specialized plugin and does an excellent job of reducing noise. Additionally, it’s rare that an entire image is affected by noise. So, by holding off on my noise reduction until I’m in Photoshop I can pick and choose which parts I need to apply noise reduction to. This is important as noise reduction degrades detail and there’s no point in losing detail in areas that are not actually plagued with noise.
  4. Reduce Chromatic Aberrations: Chromatic aberrations are annoying colored fringes, typically purple or green that can appear where dark objects are photographed in front of a bright background. They can be fixed in Photoshop, but I find that Photomatix actually does quite a good job of it. You won’t always need to use it, but the more photos you take the more you’ll be able to tell when you’re likely to experience chromatic aberrations. In this case, we’re shooting into the sun so it’s highly likely we’ll see some fringing. As you can see above I’ve selected this option.

If you’ve selected the “Selective De-ghosting” tool, as you can see I’ve done above, your next step will be to select the ghosted areas in your images. The following screen will pop up (minus the white loops, you’ll need to draw those):

 

As you can see, this scene contains a lot of movement that will result in ghosted images. The people on the beach and in the water along with the breaking waves will be particularly ghosted areas. Sometimes I’m happy to allow moving water to become ghosted as it just adds to the sense of movement or can add a nice surrealist effect. In this case I decided I wanted clear definition in the waves as they rolled up onto the shore.

There are two ways to select the ghosted areas. The normal way to do this is to draw a loop around the area by clicking and dragging. You then have to right click in the loop and tell it to mark the area as ghosted. If you select Quick Selection Mode, as I have above, you just need to draw the loop and it will select the area as ghosted as soon as you circle it. I typically go with this method. If you’re not happy with a loop you can right click inside it and tell it to delete that loop. Once you’ve made your selections you can click the Preview De-Ghosting button to see the results. If you’re not happy with what Photomatix has selected automatically, you can return to selection mode, right click in the loop you’re unhappy with and tell it which image to sample from for this area.

Once you’re happy with the deghosting you can click “OK” to process the exposures into an HDR image. This is where things get really interesting. If you’ve told Photomatix to show the intermediary 32 bit image a very strange image will be displayed. This is due to the fact that very few computer screens can display a 32 bit image. The dynamic range is too wide for them. The same can be said for inks used in printing. As a result, it’s necessary to take the 32 bit image and tone-map it. This compresses the range of colors used to those that can be displayed on screen and printed. I always tone-map using the details enhancer and never view the 32 bit image prior to processing. So, as soon as I click the OK button on the de-ghosting screen the following interface appears:

Next, click the “default” button. This is because Photomatix automatically uses the setting you used on your last photo. Clicking “default” returns the image to standard settings for you to begin making adjustments. Below you can see the image set to default. I also like to close the “Preset Thumbnails” and make the image as large as possible on my screen.

I think a lot of people probably find the huge number of adjustment sliders to play with intimidating at first. However, it’s not necessary to use all of the sliders to produce a good image. First, I’m going to focus on the sliders that I use on every image and then I’ll look at a couple others that are useful for specific situations.

I always adjust the following sliders (typically in the following order):

  1. Strength: Always ramp this up to 100. If the effect is too strong you can always back it off in Photoshop later… and the effect is rarely too strong.
  2. Lighting Adjustment: This slider adjusts the lighting in your image. If you move the slider to the left you’ll create a more “HDR-y” effect. Moving it to the right produces an image that is more in line with traditional photography. Elia Locardi over at Blame it on the Monkey states that you should never move the slider to the left as it produces unnatural results. I’m not sure I agree with this. Moving it to the left produces striking images and, with careful work later on in photoshop, can result in what I consider hyper-realistic images. I don’t really see the point in limiting the use of a tool available to you (that being said his images really are stunning, and his tutorials have helped me out a lot).

The way that I hone in on where I want the lighting adjustment is to click the extreme right and left and gradually move my clicks in towards the middle, going back and forth from left to right until I find something I like.

  1. Detail Contrast: Next, I bump up the detail contrast. As I mentioned above the huge amounts of detail possible in HDR images is something that drew me to the medium. You really just need to move this up until the image looks good to you. As you do the image will get darker, but don’t worry we’ll sort this in the next step.
  2. Luminosity: This slider will brighten the image for this so you can balance out the effects of the detail contrast. Just bump it up until it looks good. You will probably want to jump back and forth between Detail Contrast and Luminosity until you find a balance you’re happy with.
  3. Black Point: This is my last standard step for all my images. To be honest, I’m not sure how necessary it is. One of my first steps in Photoshop is effectively to do the same thing again. Images tend to look better with a bit of black in them. It strengthens the image by providing a point of reference, increasing contrast, and reinforcing lines. So, before leaving tone-mapping I always bump up the black point a bit, typically somewhere between 0.02% and 0.2%.

If you want to keep things simple you can save your image here and move onto the Photoshop phase. This is how the majority of my images are produced. However, there are a couple of sliders I’ve begun using for specific issues:

  1. Micro-smoothing: Tone-mapping is a noisy process. You can deal with this in Photoshop, but if it’s particularly bad you can lessen the problem by using the micro-smoothing tool here. It reduces the amount of contrast on small details and therefore reduces noise in large areas of uniform color, like the sky. This also brightens the image, so to reverse this I use the next slider.
  2. Gamma: I don’t actually know what the difference is between this and the luminosity slider, but I use the Gamma slider to adjust brightness without messing up the balance between Detail Contrast and Luminosity I’ve set previously.
  3. Smooth Highlights: I discovered this slider not long ago and am finding it really useful when it works. One of the issues with this method of tone-mapping is that the sky tends to end up being the same brightness as the rest of the image, resulting in unnaturally dark skies and flat images. I’ll be showing you how to fix this with Photoshop, but Smooth Highlights can fix this sometimes. I’m not sure why it works sometimes and not others, but when it works it’s like magic. If the sky looks a bit too dark for your liking, try sliding this up to a hundred to see if it has an effect, if it does you’ll see the sky magically brighten up and look beautiful again. Then slide it back a bit until you find a good level. Half the time I end up just leaving it 100.

Once you’ve finished setting your sliders and have the image looking as good as you can hit the “Process” button (you can see to the left in the below image). Save it as a JPEG and follow the link to the next page to find out what you need to do to fine-tune this image in Photoshop (coming soon).

 

 

  2 Responses to “HDR Tutorial 2: Producing HDR image and Tonemapping with Photomatix”

  1. I have a Nikon D5100 with which I have made a few HDR pictures using the built in program. I like what I see but it allows little adjustment. I have on order with Amazon a copy of Photomatix. When I get started I will refer to this tutorial, thanks for it.
    Jack

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