My free HDR tutorial as featured on ThePhotoForum.com HDR Subforum:

I put this guide together for the purpose of helping those new to High Dynamic Range (HDR) photography. 


I. Why HDR?

- Definition
- How camera sensors work, limitations
- How the human eye works

 

II. What HDR programs should you use?

- Photomatix: impressions, in-depth review of interface 
- CS5 Merge to HDR pro: impressions, brief look at interface
- Nik Software HDR Efex Pro: impressions, brief look at interface
- Luminance HDR: a brief glance

 

III. How to capture HDR photos in your camera

- Manual mode
- Auto Exposure Bracketing

 


IV. HDR Odds and Ends

- Tone mapping vs HDR
- Purists vs. Creationists

 


V. Conclusion



I. Why HDR?

Defining HDR

Using HDR allows you to capture the full dynamic range of a scene. “High dynamic range (HDR) images enable photographers to record a greater range of tonal detail than a camera could capture in a single photo.” – High Dynamic Range Photography, CIC. In short, it allows you to capture a scene as you would see it. It allows you to capture highlight and shadow detail that simply would not be possible with one exposure.

"High dynamic range imaging (HDRI or HDR) is a set of methods used in image processing, computer graphics, and photography, to allow a greater dynamic range between the lightest and darkest areas of an image than current standard digital imaging methods or photographic methods. This wide dynamic range allows HDR images to represent more accurately the range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight, and is often captured by way of a plurality of differently exposed pictures of the same subject matter." -- Wiki

How camera sensors work, limitations

When people ask me why HDR is necessary and/or how it works, I simply have them pull out their phones and open their camera app. I have them point their camera directly at a light source. When they do, I point out how the camera sensor adjusts for the bright light, essentially making everything else in the scene dark. The opposite occurs when there’s a bright source of light and you’re exposing for the scene. I pulled out my cell phone camera (you can do the same) and pointed it directly at an overhead light above me to illustrate this concept:


As you can see, when the sensor is pointed directly at the light, the sensor exposes correctly to give detail in the light source, but the surrounding areas are completely dark with no detail.


When exposing for the room and not specifically the light, the details of the light are lost. The area where the light is coming from is blown out entirely.

If you were standing in the room, your eyes would have no problem seeing all of this. You’d see all the detail in the overhead light, as well as the ambient light. The camera sensors dynamic range is much more limited than our eyes, which is why there is a need to use HDR to combine multiple exposures to recreate what the eye sees in a HDR image1.

How the human eye works

The human eye has the amazing ability to sort an incredibly huge dynamic range. “In addition to straight-up light sensitivity the dynamic range of the human eye is absolutely astonishing”—Jan Kamps, Pixiq
Dynamic range* is one area where the eye is often seen as having a huge advantage. If we were to consider situations where our pupil opens and closes for different brightness regions, then yes, our eyes far surpass the capabilities of a single camera image (and can have a range exceeding 24 f-stops).”-- Cameras vs. The Human Eye, CIC. 
It is estimated that camera sensors are limited to about 8-11 fstops.

**1.) There are other methods for capturing the full dynamic range of a scene available such as ND Grad filters and the recent Nikon D800 (the DR king) which has amazing shadow recovery (up to 5 stops) see the photo and the TPF discussion.

II. What HDR program should you use?

The most frequently asked question in the HDR subsection on this forum is “what HDR program is the best?” There are many HDR programs out there and it can be a bit of a daunting task to figure out which one(s) to use. A lot of them handle HDR very well. Most of these programs use similar mathematical algorithms to combine exposures. What ultimately separates the good programs from the great is the ability for the user to have control over each step of the process giving them ultimate control of the resulting image.

Photomatix—The best all around HDR program: 

I’ve personally used all the programs that I’ll discuss here and have found the best program for unprecedented control over HDR images from start to finish is Photomatix by HDRsoft. Photomatix offers unique advantages to other software including advanced alignment, de-ghosting, useful sliders, and extensive compression/fusion/and tone mapping control.

Alignment
Photomatix alignment algorithms are exceptional. You have the option to auto-align by matching features, which is really nice if your tripod isn’t sturdy or you shoot handheld. You can also choose to align vertically and horizontally, when shooting off a tripod.


Ghosting and Alignment by Rotanimod, on FlickR

De-ghosting
Photomatix selective de-ghosting is the best I’ve seen. Before the HDR file is created, you can select areas of a photo where there’s ghosting (such as moving people, clouds, water) and you have the option to select which exposure to use for that area of the image. In the images below, I selected the water with a longer exposure to give the water a smooth look. 

Before


Deghosting by Rotanimod, on Flickr

After 

Deghosted by Rotanimod, on Flickr

Advanced Sliders
There are a plethora of advanced sliders to help you achieve the look you are going for. This gives you creative license to do any number of things with your image once it is in the Photomatix adjustments phase. 


Sliders and options by Rotanimod, on Flickr


You can drag and drop images directly into Photomatix for processing

Drag and Drop by Rotanimod, on Flickr

The final image from Photomatix, with final adjustments in CS5:

The Beautiful Oregon Coast by Rotanimod, on Flickr


Adobe CS5 Merge to HDR Pro

Adobe has it’s own version of HDR merging software called Merge to HDR Pro which is built into CS5. Check out Cambridge in Color full tutorial on Merge to HDR Pro software here.

There are a number of differences between the programs. Photomatix is dedicated HDR software, whereas Merge to HDR Pro is software built into CS5 which is a convenient but lacking option for serious HDR shooters. It just isn’t quite up to snuff in a lot of areas. I didn’t mind using Merge to HDR Pro when I first started shooting HDR, but found the software lacking in it’s handling of ghosting, alignment and Halo-ing as compared to Photomatix. The sliders seem touchy as well, and even small shifts can create unwanted artifacts. 

Initial Merging


Merge to HDR Pro by Rotanimod, on Flickr

Resulting image with very few tweaks (notice halo-ing around the tip of the foreground rocks). 


HDR Pro Merge by Rotanimod, on Flickr


Also notice in the second image that there is a box to check for removing ghosting. That's it! A box to check. And trust me, checking that box does not always get the job done, especially if there's movement in the scene. Deghosting is nothing like Photomatix which gives you full control with selective de-ghosting. 

Nik Software HDR Efex Pro.

I like lots of the software from Nik Software—I use Viveza 2, Color Efex Pro, and Silver Efex all the time. I highly recommend all of them. But I haven’t used HDR Efex pro enough to be good at it and figure out all its quirks. Here’s the same HDR stack dumped into HDR Efex Pro… I wasn’t too pleased with the outcome, but again, haven’t used the program a ton and could probably get better results if I had more experience with the program:
Initial loading


HDR Efex Pro by Rotanimod, on Flickr

Resulting default is dark and noisy with some banding in the sky


Hdr EFx by Rotanimod, on Flickr
I also noticed with HDR efex pro that you must manually select the EV spacing before the expsoures are aligned. Photomatix and Merge to HDR Pro automatically sorted the EV spacing.

Luminance HDR 

For free HDR processing, there’s Luminance HDR. I dumped the same images in. I’ve never produced one usable image from Luminance, but I haven’t tried that hard either. I didn’t like how it handled these exposures. But if you’re on a budget and want to try something free, maybe you can get better results!


Luminance by Rotanimod, on Flickr

Really peculiar artifacting all over the image. 

LUminace 2 by Rotanimod, on Flickr

There are other notable paid programs such as machinery HDR.



III. How to capture HDR photos in your camera

Manual Mode

You can capture HDR with manual mode in your camera. It is best to use manual mode at scenes where you are shooting non-moving objects and you have a sturdy tripod.

It’s important to take a couple precautionary steps when shooting HDR manually

  • Fix your aperture, and leave it alone. You don’t want DOF to be changing between shots
  • Lockup your mirror and/or use a self-timer for each shot so there is no unintentional shake that will blur your exposure. If you have one, use a remote shutter release
  • Shoot off a sturdy tripod
  • Shoot scenes that don’t have large amount of movement

When shooting manually, I like to start my bracket to expose for the shadows first or highlights first, then work my way backwards or forward; For example, I could start at +3 EV exposing for shadows and work my way down to expose for the highlights. Each scene you encounter will have a different dynamic range, so it’s your job to determine the dynamic range. To figure out the dynamic range of a scene, I find live view and exposure simulation is helpful. If you don’t have live view or exposure simulation, simply reviewing the exposures works fine too. Make sure you have adequate shadow and highlight detail before moving on to your next shot. 

Here’s a theoretical example of my camera settings when I manually bracket at a scene with 7 stops of dynamic range. You bracket the shots by changing the shutter speed. I usually work in 1 stop increments

EXP 1: Aperture f/8; Shutter speed 1/8; ISO: 100; +3EV; Exposing for the shadows (longest exposure)
EXP 2: Aperture f/8; Shutter speed 1/16; ISO: 100; +2EV
EXP 3: Aperture f/8; Shutter speed 1/30; ISO: 100; +1EV
EXP 4: Aperture f/8; Shutter speed 1/60; ISO: 100; 0EV; this is the middle of the bracket, the best compromise between shadows and highlights
EXP 5: Aperture f/8; Shutter speed 1/120; ISO: 100; -1EV
EXP 6: Aperture f/8; Shutter speed 1/240; ISO: 100; -2EV
EXP 7: Aperture f/8; Shutter speed 1/480; ISO: 100; Exposure for the brightest highlights.



Auto Exposure Bracketing

Bracketing exposures is an incredibly handy feature for the HDR shooter. Being able to shoot of a deep bracket (7-9 stops) with one click of the shutter is an extremely convenient feature. Why? Deep bracketing is the difference between power windows and manual windows… Both get the job done, but power windows are surrrrrrre nice.

To understand why deep AEB is critical to the HDR shooter, it’s important to look at the alternative to AEB: bracketing manually. There are two reasons why bracketing manually isn’t always desirable.

  1. you are adding duration between shots which can cause problematic ghosting for scenes with movement (water, people, clouds)
  2. you risk moving the camera which can cause alignment issues (especially if your tripod is not rock solid, or you have a tendency to bump your camera when fidgeting with dials like me)

Imagine shooting a sky where the clouds are moving quickly or a scene where leaves are being blown in the trees. Even 1 or 2 seconds of dial adjustments can be the difference between a usable exposure stack, and one that is ruined because of ghosting and alignment problems. The faster you can acquire your exposure stack, the better. That’s why Auto Exposure Bracketing is optimal for these types of scenes. Many cameras allow for brackets up to 3 stops. For scenes with a high dynamic range and movement, 3 stops isn’t always enough to capture the full dynamic range.

How deep is the bracketing in your camera? Check here to find out. So you followed that link, and you've found your camera has AEB, and you’d like to use it. Check your cameras manual to learn how to enable the feature. When setting up AEB, I keep my 0EV at the best compromise of the highlights and shadows. It’s usually best practice to bracket in 1 stop increments, but if that’s not adequate to capture the full dynamic range, you can always bracket the highlights and the shadows for 6 stops of total DR information. I’ve also bracketed handheld at -2,0,+2. It’s not best practice, but it can get the job done. 

Most Canon cameras besides the 1D series and the 5d Mark III only allow for 3 stops of AEB. Conversely, many of the middle range to high end Nikon cameras allow for deeper bracketing. Here is a video of Trey Ratcliff shooting Crater Lake where he demonstrates the usefulness of bracketing and provides some good discussion of HDR in general. 
[video=youtube;itGUk5yk2ow]http://www.youtube.com/watch?v=itGUk5yk2ow"][/video]

IV. HDR Odds and Ends

Tone mapping vs. HDR 

A lot of people confuse tone mapping with HDR. They are not the same thing. The confusion probably comes from the fact that tone mapping is a part of the HDR process, so tone mapped single exposure photos have the "HDR look" to them. However, a tone mapped photo is not an HDR photo. “Tone mapping is a technique used in image processing and computer graphics to map one set of colors to another in order to approximate the appearance of high dynamic range images in a medium that has a more limited dynamic range.” – Wiki.

A single exposure of a tone mapped image does not have the dynamic range of an image with multiple exposures. 

Creationist vs. Purists

HDR photographers usually fall somewhere in between the creationist (those who push HDR to create surreal and/or unrealistic images) and the purist (those who take a more subtle approach and whose photos yield more natural outcomes). 
I gravitate towards the purist camp when it comes to HDR. 

I use HDR mainly as a tool to capture the full dynamic range of a given scene, and typically gravitate more towards photo-realistic processing. However, I do see the benefit and enjoy the extra punch creative processing can give to a photograph, and will sometimes employ these methods in my own work. 

V. Conclusion

No matter which side of the fence you fall on, whether you are a creationist or purist, it’s critical not to allow HDR to come before the other important fundamental concepts of photography such as exposure and composition. The old saying goes "Don't put the horse before the cart". Don't put HDR before your understanding of photography. HDR is a tool in your toolbox to enhance your photography, but it should not substitute for the basics of photography. After all, a poorly composed and exposed picture is still a poorly composed and exposed picture even after HDR treatment. 

Thanks for reading. I hope you may find some of this information helpful on some level. HDR is an exciting branch of photography that opens up the ability for the photographer to capture photographs like never before. HDR allows you to capture the full dynamic range of a scene and emphasize textures, contrast, colors, depth, and light in a photo like never before. Most of all, it's fun!