HDR

All posts tagged HDR

EDITOR’S NOTE: Guest post by Trey Ratcliff. Trey is the publisher of StuckInCustoms.com. He’s also the author of the new book “A World in HDR“. The site is well known for HDR Photography and his free online HDR Tutorial.

Scott Bourne recently mentioned something to me that really struck a chord. He told me how surprised many people are when he mentions in classes that you can make HDR (High Dynamic Range) images in black and white. I told him I got the same reaction, and I thought it was just localized to me because my photos are normally so colorful. By sharing this little experience with me, now I can see this may be of universal interest, so I should write a little article about it!

HDR is about light; it’s not about color. If you consider yourself a colorist, like me, then you do tend to gravitate to light with color. After all, that is the world in which we live. Monet, the Impressionist painter, whose tonemapped landscapes shocked the establishment, said, “Shadows are not black. No shadow is black.” For most ambient daylight situations, this is absolutely true. We can indeed have some dark shadows, but these are often at night, indoors, or with man-made lighting situations. B&W photography and HDR photography are thought to be worlds apart. Whenever I speak to groups, there is a consistent 20% or so that absolutely hate HDR, won’t like it, and never will. Then, there is about another 20% that leans on what is rapidly becoming an annoying old saw, “I like HDR, but only if it is subtly applied.”

Swallowing the Ruins

Swallowing the Ruins – Creative Commons, no commercial use, Trey Ratcliff

It is curious to me that B&W photographers are often the first to criticize HDR as being “unrealistic”. If I were to retort that the world is indeed NOT black and grey and white, so their photography is intrinsically unrealistic, this is often met with scoffs because it is already a respected niche. However, once we get past all these ridiculous pedantic arguments (which I always feel like I win because I honestly don’t care as much as the other party in the argument,) we can start to discuss how light works. For artistic reasons, many B&W photographers can crank up the shadows and lights to make hard edges, wonderful shapes, and enshroud the photo with mystery. After all, that emo kid in the corner with the stupid hat looks so much more emo when the hard shadow falls across his pierced nose. Wonderful! Okay, so that form of B&W photography is alive and well, and it will always be an option for people who want to play around within well-established genres.

The edges of the Flatiron

Afternoon at the Flatiron – Creative Commons, no commercial use, Trey Ratcliff

So, what’s going on with an HDR B&W anyway? Good question! Let me see if I can explain it. I will assume that your eye can indeed see more light levels than your camera can capture. Like Ron Burgandy said, “It’s science!” The goal is to get all the light levels your human eye can see into the final image. First, for those of you that have seen my new HDR book “A World in HDR” or read the online HDR Tutorial, you know that HDR photos are often (but not always) shot by taking three or more exposures at different shutter speeds. We are all familiar with “compositing” photos, in which we might take the blown-out area of one photo and replace it with the perfectly exposed area of another photo. This was a painstaking process before photoshop, but it’s still no cake-walk in there either. I wanted to say this because HDR is not this simplistic compositing in which you can take big “chunks” of a photo and replace them with other perfectly exposed chunks from other photos. The HDR process will take those multiple exposures and mix them all together on the pixel-by-pixel level. It would be the same as a human doing back-breaking compositing by looking at each individual pixel and choosing which of the three images the final one should come from. Crazy! We can let the software (which I recommend in the HDR Tutorial), do the same thing that the human brain does when interpreting light levels. I prefer to use the software to make a color version and then convert to B&W later in Photoshop. Then, you can mess with the greens and blues and all those crazy things you know you like to play with. You’ll see wonderful little light details and textures that maybe you have been missing for years.

The Forgotten

An abandoned ruin in Cambodia – Creative Commons, no commercial use, Trey Ratcliff

I invite you to try this and compare it to a “regular” B&W photo. You can also make HDRs from a single RAW file (see above links), so perhaps you have some old ones sitting around. Try it with a handful of images and then look at them side by side. Maybe you will find something unexpected! Little Warning #1: Be careful of the HDR process on human skin. Just as in the situation with flat blue skies, the algorithm gets a little confused and can cause problems. In these cases, just mask in the original RAW where the skin resides. Little Warning #2: This is a fun and addictive thing. You may miss out on the birthday of a loved one or something, so it’s best to try this in measured doses.
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EDITOR’S NOTE: Since Trey and I are leading a workshop together, I won’t be reviewing this book since some would see it as a conflict of interest. However, our regular book reviewer, Conrad Obregon has a review, which we publish now.

Author: Trey Ratcliff

Publisher: New Riders Press

Review by Conrad J. Obregon

There are good words in the English language that have bad connotations. One of them is flippant. That’s a shame, because it would certainly be nice to describe Trey Ratcliff’s language in A World in HDR as flippant, without disparaging the book.

This book has two different themes. The first is as a collection of travel photographs from around the world. Opposite each photograph is a commentary in which Ratcliff provides his thoughts about the image. For example, in showing a photograph of a monkey in Malaysia, the author discusses thinking about how things are named, and the place of monkeys in the context of the larger world around them, and even of how a photograph can be used to start a discussion.

The book is also about High Dynamic Range (HDR) imaging, a process of extending the range of light in photographs by combining differently exposed images of a subject. All of the pictures are made using HDR techniques. There is also a short tutorial on HDR processing with an emphasis on the techniques Ratcliff favors.

When reading this book, it’s useful to keep in mind the dual nature of HDR imaging. On the one hand HDR can be used to capture a range of tones equal to the human eye, rather than the more limited range of a camera, and thereby create what is actually a more realistic photograph. At the other end of the scale, HDR can create surreal pictures with vivid colors and abnormal lighting effects that are more like illustrations. Both effects can be used to convey the vision of the particular artist. Ratcliff appears to prefer the surreal extreme. (Indeed, he doesn’t even discuss the exposure fusion function of the Photomatix Pro software, which can be used to merely extend the range of light.) Readers should remember that surrealism is not the only option.

Readers unfamiliar with Photomatix Pro, which is rapidly becoming the standard software for HDR processing, may prefer a little more detail. One book that I found useful for early encounters with Photomatix is “Practical HDR: A complete guide to creating High Dynamic Range images with your Digital SLR” by David Nightingale. On the other hand, more experienced users may find some of Ratcliff’s suggestions useful. For example, even though it’s a standard Photoshop technique for local adjustments, I’d never encountered or applied the advice to blend the HDR image with the original images to tone down surrealistic effects or deal with image motion.

Strangely enough the author’s breezy language is one of the reasons I recommend this book. It helps to convey the idea that creating images can be fun.

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Author: David Nightingale

Publisher: Focal Press (Elsevier)

Reviewer: Conrad J. Obregon

A physicist acquaintance who specializes in digital imaging tells me that increasing resolution or reducing noise in digital sensors are much easier problems to solve then extending the range of light of sensors to equal the human eye. In the unlikely event that you are a serious photographer who has been waiting for the dynamic range of digital sensors to increase rather than deal with high dynamic range (HDR) it would be better to get over it. This book is an excellent place to start.

Nightingale’s book, Practical HDR: A complete guide to creating High Dynamic Range images with your Digital SLR is divided into chapters that include understanding dynamic range, shooting for HDR, merging bracketing sequences, creating photo-realistic and hyper-real HDR images, and post-processing.

The author recognizes that there are many HDR software packages on the market and rather than try to describe them all, he only touches on three. They include Photoshop, which at least as far as the CS4 version, he dismisses as not very useful, and the quirky but occasionally useful FDRTools. The lion’s share of the instruction is devoted to Photomatix Pro, which is rapidly becoming the standard for HDR. Unlike several other texts, he explains what each of the sliders and buttons in Photomatix does and what compensating adjustments have to be made if you select one of the more specialized sliders. He also covers post-processing of HDR images in Photoshop at a level of detail sufficient for those familiar with Photoshop to clean up the HDR image, rather than just suggest the tools that might help. He also provides several examples that give detailed step-by-step explanations of how he used the options available in both HDR software and post-processing and the reasons he selected those settings. Sprinkled throughout the book are HDR examples created by several expert photographers.

Nightingale writes concisely and clearly. I particularly liked that he distinguished between images where the range of light was extended but the images remained realistic, and HDR images that seem almost surrealistic and more like illustrations than photographs. The author shows you how to create both types of image, and clarifies which controls lead to which results.

Although this is one of the best books about HDR that I’ve encountered it is not perfect. For example in capturing images, I’ve found that it pays not only to insure that the bracketing images are made by varying the shutter speed rather than aperture to keep the same depth of field, but also to turn off auto-focus and auto-white balance to prevent too much variation from image to image. Moreover, when it comes to processing, other than to refer to FDRTools’ capabilities to deal with motion between bracketed images, there is little other discussion of the motion problem. On the nice-to-have level, it could have been useful to deal with tools like Photomatix Pro’s Lightroom plug-in which extends the utility of the software. Similarly, providing images that were downloadable or on a disk might have made it even easier to follow the examples, especially with available trial versions of the HDR software.

Nevertheless, I still find this one of the best books available on the subject, and I intend to keep it in the small library of books next to my computer to which I regularly refer.
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Image and Post by Rick Sammon – Follow Rick Sammon
on Twitter

A Quickie From Mt. Rainier

Made this image (HDR, 3 images) on the way to meet my buddy Scott Bourne at the Mt. Rainier Aperture Nature Photography Workshop today. Hanging out right now with photo pro (and hell of a nice guy) Juan Pons. Great group. Great location. Great fun – except none of our iPhone can get a signal. . . and the internet is sloooooow.

Re the image: I used Photomatix Pro to create the HDR image. then converted it to B&W with Nik Silver Efex Pro.

400x80TWIP

Copyright Scott Bourne 2009 - All Rights Reserved

Copyright Scott Bourne 2009 – All Rights Reserved

This is a collection of 20 random HDR tips that you might find useful. These tips are based completely on my own experience. I use this information like a checklist (which I now have memorized) every time I go shoot an HDR. Your mileage may vary.

1. Use a tripod
2. Shoot at your lowest useable ISO
3. If possible, shoot in RAW mode
4. Don’t vary the ISO when you make your series of shots
5. Don’t vary the Aperture when you make your series of shots
6. Don’t vary the White Balance when you make your series of shots
7. Set your autofocus mode to continuous or equivalent
8. Shoot in manual mode and vary shutter speed to get different exposures
9. Use a cable release or self-timer
10. For BEST results, shoot five or even seven frames, depending on how much contrast is in the scene
11. Make sure your darkest shot doesn’t contain ANY blown out details
12. Shoot until the darkest shadows are well lit
13. Shoot in one stop increments.
14. Merge to HDR in Photoshop as 32-bit image
15. Avoid shooting scenes that contain movement or you risk artifacts
16. Export HDR image to Photomatix Pro
17. Create a Tone Map in Photomatix Pro
18. Round trip to Photoshop for additional cleanup
19. Don’t forget that your color HDR image may even look better converted to monochrome
20. Save and share

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