HDR How-To

How do I shoot and process an HDR Photograph?

Update 10/4/2011 The Original post has been updated to show the new interfaces and features of Photomatix Pro 4.1

This will give you the quick and short method to shooting and processing. There will be a lot more things to cover along the way but I will do them in posts to the blog. This will get you started and allow you to experiment and get used to the process of shooting for HDR and how to bring it all together in your computer.

First off, the equipment you will need:

A camera that is capable of manual operation or exposure bracketing in Aperture Priority mode. This would be almost all DSLRs and some Point & Shoot digital cameras
A Tripod, nice good quality steady one
A remote shutter release, although it is possible to use your timer or just press the shutter button. A shutter release can give the ultimate results
An HDR Processing program. Now I always recommend PhotomatixPro 4.1 from HDR soft. I have tried a lot of different programs but I still think it is the best. There are plenty more and you can even use Photoshop CS2 or later to process HDRs. Photomatix does have full function trial you can use to see if you like it before you buy. But it will watermark your images. For 15% off your purchase of any Photomatix software, enter the coupon code: theHDRimage at checkout. It’s available in a lite version, The Pro version which is a standalone with Plug-ins for Lightroom, And as a plug-in tone mapper for Photoshop and Aperture

So it’s time to shoot.

We want to capture the highest dynamic range for each image even if we are shooting multiple exposures. So if your camera is capable of shooting RAW or Tiff format, do so. If you are not comfortable working in either of those formats, you can shoot JPEGs, it will still work fine even if it is not the ultimate in quality.

First we need to determine a good subject and lighting for HDR. Landscapes are a natural for it but best early morning or late in the day when the light get more contrasty or has more Dynamic Range, which is what of course we want. Architecture is good, interior architecture especially, Vehicles work great. Remember we are looking for a subject that we can’t capture well with normal photography, in fact if you can get it right without HDR, do it. People or portraits or really any object in motion are not good for HDR because remember we are going to be taking multiple exposures and any movement in between those images will cause ghosting or worse in our image.

Now that we have selected our subject we need to shoot our images. For this basic tutorial we are going to shoot 3 Images at 3 different exposures. We are going to use either manual mode or Aperture Priority Auto. We choose Aperture Priority over Shutter priority because we want out Aperture and therefore our Depth of Field constant.

So let’s talk about setting our aperture first. I think it should be shot with a very deep Depth of Field (DOF) so I always shoot my HDRs with a smaller Aperture. I usually shoot at f16. on my Full Frame camera that gives me the maximum DOF without getting some softness issues that occur at even smaller apertures, If you are shooting with a cropped DSLR you should probably shoot around f11 and if using a Point & Shoot f8 will be fine. But the point is we need to use the same aperture for every shot.

With our aperture set we need to take our 3 shots. We need to have each shot 2EV or 2 stops apart. So if in manual mode and reading your meter that would mean we want 1 shot each at 0, -2 and +2 on the meter.It’s important for our 0 exposure that we meter on a midtone and not the brightest or darkest area of our scene. This may be the blue sky or some green grass but don’t meter your 0 exposure on say the sun or the dark shadows. You will get a much better image with good metering techniques. If you are using Aperture priority mode on your camera that can do exposure bracketing. We want to set our bracketing at 3 exposures, 2 stops apart. (some Nikons can only do 1 stop apart so do 5 exposure, 1 stop apart) All set?

Now take 3 images carefully shooting so there is no camera movement. Remember our software is going to have to line up 3 images so the less movement between each shot there is, the sharper your final image will be. Some people like to know where the 3 exposures start and finished so they may take a picture of their hand in between each group but you really can only do this with manual mode since it will mess up your bracketing since you are adding a 4th shot.

If you did things right you should have three images that look similar to this:

With your images shot you are done. One of the fun parts for me is that when I am actually shooting I never know what I really have. It kind of goes back to the days of shooting film when you weren’t really sure what you had till the photos were developed. Those old days before LCD screens on the back of our cameras.

Once you return home download your images to your computer and open them to view in an appropriate software. If they are RAW files you may need to open them in Bridge or Lightroom or your original RAW software that came with your camera. But you want a browser that you can see your images and to define the file numbers for your sets of 3 images.

Now open up Photomatix, The software we are going to use in this tutorial.

The first panel you will see is this one

Click on the “Load Bracketed Photos” button and it will open another dialog box that you can browse for and find your images you want to combine into your HDR.

After you have selected your image and clicked OK your next dialog box should look like this:

Starting from the top of the panel

Align sources will be checked, I normally do “By Matching Features”
You will notice a Crop Aligned Images box. When Photomatix aligns the images, if the images are really off in alignment it will crop the image to get the bad edges off, sometimes this leads to an image slighly off from the regular 2:3 photo image so you may need to crop later to bring it back to a standard aspect ratio.

There is a check box for Include Perspecive correction”, I keep this checked also. As an image may be twisted from image to image you may get some perspective distortion say to the shape of a building. This helps pull those lines together

Reduce Chromatic aberrations I usually check also, it stop the blue fringing that is common place on areas of extreme contrast.

Reduce noise: I never use. There are way better noise reduction programs out there that I will use later if necessary.

Remove Ghots> I will use if there are things in the image that this may be a problem, people or water moving. But if it is not necessary I keep it off. Most times I do leave it off. However I will say the “Selective Deghosting tools is one of themost powerful parts of Photomatix Pro 4.1 that sets it apart from other software for Alighning and Deghosting. I have a seperate post on how to use this once you get udsed to doing the basics

The last two boxes For white Balance and color space. Choose the color space you edit in. If you DON’T know what that is choose sRGB. And white balance I leave as shot. If there are really problems with white balance I corrected them In my RAW editing program and then save the file as a TIFF to open in Photomatix instead of a RAW file. It is much more precise

Then again Click OK and Photomatix will process the 3 images into a 32bit HDR image

It will look somewhat like this, pretty ugly huh?

That is because no monitor available now can display a 32 Bit HDR image. So now we have to take this image and “Tone Map” it so that it is visible on our monitors and can be printed if we desire.

Also at this point you can go to File> Save and save this as a Radiance RGB HDR file. This will allow you to reopen the original HDR file and rework it if you don’t like what your first attempt at tone mapping did. It eliminates having to do the first 3 steps again.

Now we click on the Tone Mapping/Fusion and Our Tone Mapping Screens Open up. (click to enlarge)

On the left is our adjustments panel, at top or our zoom functions along with a Selection check box which we will discuss later in another blog post. On the right or down below, depending on Image orientation, are presets. The presets are good because they allow you to see many different styles of HDR, from mild to wild and you can see where the adjustment controls move to for different looks. After you get used to working with Photomatix Pro 4.1, you may come up with your own presets just like I have with your favorite setting, which you can save as custom presets

At the top are two buttons, One for Tone Mapping, one for Exposure Fusion. Exposure Fusion is more like what you would get from Two Exposure Blends, which is fine but not what we want. We want to use Tone mapping and under that the Method Drop down gives us two choices. The tone compressor is fine if you want a very natural looking image but really isn’t that powerful. I prefer detail enhancer not because I want something that looks unnatural but just that is gives me much more control and the ability to fix problems that may pop up in an image.

This panel is set up with the most important settings at top and they work their way down in order of importance or use.

The two most powerful controls as we work down the panel are Strength and Lighting Adjustments. In the Lighting Adjusment panel check the box for Lighting Effects. This again will give you more powerful choices.

Between Lighting Adjustements and Strength, these two controls will adjust the differences between brightness and shadow and the intensity of those areas. Go back and forth with both of them until you get the desired look you want, without ugly artifacts that can be a side effect of too much or too little of each other.

I usually start with Natural and then move the Strength bar back and forth till I find what I want. But depending on the image and what I am looking for I may go up to Natural +or down toMedium or Surreal, again adjusting the strength to get where I want to be.

Luminosity will raise or lower the global brightness of the image, once you get the ratio you want of bright to dark, this will bring it all up or down.

Detail Contrast can bring in more detail to the image by increasing contrast at edges.

Color Saturation, I usually raise up a bit because with the blend of three images at extremes can make the image look a little flat color wise

Moving down to the next section, Under More Options. These are your tone controls. Smooth Highlights is a good control to know if you get a lot of Haloing or white glow around objects. using this control can lesson those artifacts

White point affects bright tones, Black point affects dark tones and Gamma affects Mid-tones. Gamma is the control in this section I use the most. Since again when we blend the 3 images it tends to make the whole image more towards mid-tones and we need to bring some contrast back to it.

The rest of the controls we won’t worry about for now, I will talk more about them in other lessons in the blog. They are very helpful when you run into problems with an image such as Burnt Edges (dark areas surronding areas of brightness) or haloing. But if we do things right from the start, we may not have to deal with those problems.

This is our merged image before any tone mapping

For our sample image, I set Strength at 80, Smoothing at high , Saturation at 70 and then Gamma at -1.20 and that was about all I had to do and this is my result for a look as I saw the scene when I shot it.

If this is the look you want, go to File > Save and save the image. I prefer to save it as a 16bit Tiff file and then maybe do some Final Adjustments in Photoshop. But you also have to option to save as a 8 bit JPEG file.

Now this is an example of how wild you can get with things, Definitely not my taste at all. But a lot of people like looks similar to this. It’s all in your hands and your artistic vision