NatureScapes.Net - The High Dynamic Range (HDR) Landscape Photography Tutorial

Published July 2006

An input image alignment function patterned on the adjustable tile system in Panorama Factory. To me, fixing alignment problems before they are “set” is preferable to fixing them at the end using cloning and healing techniques in Photoshop. More control over HDR alignment would be helpful.

Arbitrary preview zooming like that in CS2, showing the “real” tone-mapped pixels rather than a simulation. Or perhaps a pop-up magnified viewer window (similar to the HDR image viewer in Photomatix or the small magnified view shown in most CS2 adjustment panels) showing 100% pixels after applying all tone mapping. This is somewhat limited by computing power, but I prefer to work directly on the “real” image rather than shuttle between simulations and generated actual images, iterating on changes because I can’t really see what I’m doing.

Tone curve editing with slider type controls as in Photomatix supplemented by curve editing like CS2, showing “before and after” histograms. (CS2 shows the “before” histogram, while Photomatix shows “after.”) The “before” histogram tells me where the HDR image data is, and the “after” one shows how my tone mapping settings affect the final data distribution; both are useful. Interestingly, the initial Adobe Lightroom beta release did not contain point curve editing. Instead it introduced a slider control system for tone curve adjustment, offering quick, qualitative adjustments across highlights, shadows and midtones. Sometimes editing points on a curve, for all its precision and flexibility, does not quickly or easily produce desired results. Point editing is expected to be added into Lightroom’s curve adjustment. This would provide the best of both worlds – quick, qualitative controls to “get in the zone,” and precise controls for fine tuning. This capability with HDR tone curves would be a plus.

Adjustable detail and noise controls in the HDR conversion function, such as what can be done with a number of RAW converters, and is present (though somewhat rudimentary) in Photomatix. The idea is to apply quality enhancements while the maximum image data is available. The HDR file is like a RAW file on steroids in some respects, and some adjustments that can be made to a normal RAW file prior to conversion make sense for an HDR image as well. Of course in CS2 a number of filters and functions can be applied to the HDR file; this may be an argument in favor of using CS2 to generate the HDR and pre-process it, then use the Photomatix plug-in to tone map it. I have not tried this yet but plan to do so.

The ability to mask HDR tone curve adjustments to apply them to selected parts of the image. Also, the ability to apply certain level of local contrast enhancement to different degrees across different parts of the curve. Adobe may end up going in this direction if they add 32-bit layers to a future release of Photoshop. This would open up much of the selective adjustment ability that currently is not possible with either the CS2 or Photomatix tone mapper.

The ability to combine several RAW files directly into an HDR file without having to convert to 16-bit TIFF images first. Very few adjustments need to be done when making RAW conversions targeted at HDR processing, so why not skip that step altogether? Some of the more niche HDR tools appear to support this, at least for certain RAW file formats.

And if we are thinking of all of this, then how about an affordable DSLR that can produce an HDR image straight out of the camera? And a monitor and other output devices capable of presenting those images. These devices are being worked on, of course, but are still a ways out from being accessible to folks like me – I am sorry to say I do not have the cash for a Spheron HDR camera or Brightside HDR display.



Published July 2006 Stitched panorama of the sunrise at Lake Minnewanka, near Banff, Alberta (the same scene used for the main example image in this article): Photo 1 Single frame image of ice and flowing water at Johnson Lake, near Banff, Alberta: Photo 1 New Images Some of these have appeared as examples in this article up to this point. Single frame image of afternoon clouds at Lake Minnewanka: Photo 1 Single frame image of a sunset view near Beaverhill Lake, Alberta: Photo 1 Stitched panorama of a sunset over Upper Waterton Lake, Waterton National Park, Alberta: Photo 1 Single frame and stitched panorama of a sunset view across Upper Waterton Lake: Photo 1 Photo 2 7. Conclusion And now for some soap-box thoughts. It isn’t that bold a prediction to say that, one day soon, HDR technology will extend the definition of what is “normal” in photography. In the past, photographic technology has always imposed drastic limits on the dynamic range that could be captured, developed, displayed and printed. Improvements in the capability to deal with DR were marginal, and took long periods of time to occur. More success was had by photographers working within the technical limits of their equipment and media, using creativity and technique to realize compelling images despite the limitations. Those who paint and work in other visual art forms have had centuries to grapple with and develop styles, techniques and materials that permit them to communicate their visions of the natural world using media that can not represent the full range of light in nature. In photography, HDR imaging now provides a unique capability to take a significant step towards the true DR present in natural scenes. A quote I recall seeing, but have been unable to track down, stated something along the lines of “the apprentice sees the subject, the journeyman sees the composition, and the master sees the light.” Now photographers can not only see the light but can work with it in a new way to develop their images of the natural world. Setting aside what the photographers’ original intentions may have been, many HDR images floating around the Internet can be described as “unnatural,” “cartoonish,” “unreal” and so on. If photography is expected to portray the natural world in a way that is somehow more faithful than other visual arts, it behooves landscape and nature photographers working with HDR to find a combination of tools, technique, style and vision that does not violate the expectations of viewers. No doubt the proper place and use of HDR in nature photography will be disputed to some extent, as was (or is) the case for other techniques such as digital exposure blending, and shooting multiply exposed frames in film. There is room in the community for a variety of styles and interpretations; it keeps us all honest. I personally feel it is legitimate to use the capabilities of HDR to present photographic images that challenge preconceptions of what a nature photograph (such as a panoramic landscape) should look like. The images I have worked on strike a chord for me, showing aspects of scenes that are “true” to my perception and evoke a “true” emotion, even if the technical facts of transformations like local contrast enhancement violate certain “rules.” HDR photographs may not qualify as documentary work, but for me they certainly can qualify as “natural world” art in photographic form. One thing that can be counted on is that HDR tools in general are not standing still, nor is our understanding or use of them. Among the major vendors, for example, Adobe has invested in bringing 32-bit functionality into Photoshop starting with CS2 (as well as other applications in its video line). What we see in CS2 today is only the initial round of a new technology base. It is sure to improve over time. Meanwhile an advantage of smaller, more specialized companies like MultimediaPhoto and others is that they potentially can react faster to opportunities for technical innovation and requests from their customers. Future developments in HDR tools should create more exciting opportunities for photographers. But if you are interested in working with large dynamic range in your images, I hope this article helps convince you not to wait – start today! Wish List I could wish for a number of things down the road, integrated within a single tool. A few items from my wish list include: An input image alignment function patterned on the adjustable tile system in Panorama Factory. To me, fixing alignment problems before they are “set” is preferable to fixing them at the end using cloning and healing techniques in Photoshop. More control over HDR alignment would be helpful. Arbitrary preview zooming like that in CS2, showing the “real” tone-mapped pixels rather than a simulation. Or perhaps a pop-up magnified viewer window (similar to the HDR image viewer in Photomatix or the small magnified view shown in most CS2 adjustment panels) showing 100% pixels after applying all tone mapping. This is somewhat limited by computing power, but I prefer to work directly on the “real” image rather than shuttle between simulations and generated actual images, iterating on changes because I can’t really see what I’m doing. Tone curve editing with slider type controls as in Photomatix supplemented by curve editing like CS2, showing “before and after” histograms. (CS2 shows the “before” histogram, while Photomatix shows “after.”) The “before” histogram tells me where the HDR image data is, and the “after” one shows how my tone mapping settings affect the final data distribution; both are useful. Interestingly, the initial Adobe Lightroom beta release did not contain point curve editing. Instead it introduced a slider control system for tone curve adjustment, offering quick, qualitative adjustments across highlights, shadows and midtones. Sometimes editing points on a curve, for all its precision and flexibility, does not quickly or easily produce desired results. Point editing is expected to be added into Lightroom’s curve adjustment. This would provide the best of both worlds – quick, qualitative controls to “get in the zone,” and precise controls for fine tuning. This capability with HDR tone curves would be a plus. Adjustable detail and noise controls in the HDR conversion function, such as what can be done with a number of RAW converters, and is present (though somewhat rudimentary) in Photomatix. The idea is to apply quality enhancements while the maximum image data is available. The HDR file is like a RAW file on steroids in some respects, and some adjustments that can be made to a normal RAW file prior to conversion make sense for an HDR image as well. Of course in CS2 a number of filters and functions can be applied to the HDR file; this may be an argument in favor of using CS2 to generate the HDR and pre-process it, then use the Photomatix plug-in to tone map it. I have not tried this yet but plan to do so. The ability to mask HDR tone curve adjustments to apply them to selected parts of the image. Also, the ability to apply certain level of local contrast enhancement to different degrees across different parts of the curve. Adobe may end up going in this direction if they add 32-bit layers to a future release of Photoshop. This would open up much of the selective adjustment ability that currently is not possible with either the CS2 or Photomatix tone mapper. The ability to combine several RAW files directly into an HDR file without having to convert to 16-bit TIFF images first. Very few adjustments need to be done when making RAW conversions targeted at HDR processing, so why not skip that step altogether? Some of the more niche HDR tools appear to support this, at least for certain RAW file formats. And if we are thinking of all of this, then how about an affordable DSLR that can produce an HDR image straight out of the camera? And a monitor and other output devices capable of presenting those images. These devices are being worked on, of course, but are still a ways out from being accessible to folks like me – I am sorry to say I do not have the cash for a Spheron HDR camera or Brightside HDR display. References Here are a few references to additional HDR tools and information that I found interesting, and which may provide you with further ideas. Tools Photoshop CS2: http://www.adobe.com/products/photoshop/. The dominant image editing application, by Adobe. Photomatix Pro: http://www.hdrsoft.com/. A tool by MultimediaPhoto SARL for working with HDR images. Available as a stand-alone product or CS2-compatible plug-in. Autopano Pro: http://www.autopano.net/. A commercial tool that grew out of an original front-end for the free PanoTools, and claims to support both stitching panoramas and HDR processing in one application. I hope to test this soon. Radiance: http://www.radiance-online.org/. The first HDR tool, originally developed by Greg Ward. Used for ray-tracing imaging and modeling. HDRShop: http://www.hdrshop.com/. One of the first HDR tools, currently licensed by the University of Southern California. Originally co-authored by Paul Debevec. Photogenics HDR: http://www.idruna.com/photogenicshdr.html. A commercial product by Idruna for HDR drawing and image processing. PhotoImpact: http://www.ulead.co.uk/pi/. An image editing application by Ulead Systems which has supported HDR for at least the past two major releases. Contains some useful looking image combination features, including the ability to brush over areas from input images that will be explicitly excluded or included in the final HDR image. HDR Tutorials “Merge to HDR in Photoshop CS2 – A First Look:” http://www.luminous-landscape.com/tutorials/hdr.shtml. The first article and tutorial I ever read on HDR, by Michael Reichmann. It got me interested in the technique because of the way Reichmann described the potential for HDR, not just stating what buttons to press in which tools. “HDR: High Dynamic Range Photography:" http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm. A short but useful overview of HDR in CS2, by Sean McHugh. This is the best single HDR tutorial I found in my early digging into the subject. Have a look at McHugh’s gallery. I don’t know how many (if any) of the images may have benefited from HDR work, but they are some gorgeous examples of low-light architectural photography. “Stitched HDRI:” http://www.gregdowning.com/HDRI/stitched/. A brief tutorial by Greg Downing (not the NatureScapes.Net co-founder – another Greg Downing!) He is a practitioner of HDR imaging and gigapixel panoramas, among other things. In the tutorial, he gives an overview of creating multi-row stitches of several exposure sequences, and then processing them into a tone-mapped HDR image. Tools used in his example include Realviz Stitcher and HDRShop. “Photoshop HDR 32-bit Format: The Dawn of a New Era?” http://www.earthboundlight.com/phototips/photoshop-cs2-hdr-32bit.html. Another introductory CS2 HDR tutorial, this one by Bob Johnson. “Photomatix Makes HDR and Blending Easy:” http://www.atncentral.com/Pages/Photomatix.htm. A very brief overview of using Photomatix for HDR image work. By Jim Lewis of Action Central. “High Dynamic Range:” http://www.digital-fotofusion.co.uk/pi/archive/2005/11/high_dynamic_ra.html. A brief tutorial by Phil Preston on using Ulead’s PhotoImpact application for HDR. DR and HDR Information “FAQ – HDR image for Photography:” http://www.hdrsoft.com/resources/dri.html. Some good information from the makers of Photomatix regarding DR and HDR in digital imaging. “Making fine prints in your digital darkroom: Tonal quality and dynamic range in digital cameras:” http://www.normankoren.com/digital_tonality.html. Some material from Norman Koren, comprehensive as usual, about DR in digital imaging. “High Dynamic Range Image Encodings:” http://www.anyhere.com/gward/hdrenc/hdr_encodings.html. Greg Ward’s paper on HDR image encodings. A good technical read if you want a nuts-and-bolts understanding of how HDR image formats work and why, with side trips in color spaces, gamma encodings and so on. “The Future of Digital Imaging – High Dynamic Range Photography:” http://www.cybergrain.com/tech/hdr/. An interesting, mostly non-technical article by Jon Meyer covering the motivation for HDR and a survey of some of the technology. Also provides some context from the world of painting. “High Dynamic Range Imaging: Acquisition, Display, and Image-Based Lighting:” Morgan Kaufman Publishers, 2005. The only book currently available on HDR, as far as I know. Written by Reinhard, Ward, Pattanaik, and Debevec, several of the early researchers and developers of HDR imaging. Very technical, targeted mainly at HDR implementers rather than photographers or other users of the tools. Royce Howland gets paid primarily for work in the information technology field. He was first introduced to film photography at a young age by his grandfather, with the gift of a Minolta 35mm camera. After many years of preoccupation with technology and business, he rediscovered an interest in the outdoors as a birder. This led once again to photography, first casually digiscoping with Nikon point and shoot digital cameras and later more focused efforts with Canon DSLR's starting with an EOS 10D. His photographic interests are wildlife, particularly birds, and recently high dynamic range stitched panoramic landscapes. Page: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Feel free to send your comments on this article to the at NatureScapes.Net. All content on this site is copyrighted material as indicated. Unauthorized use or reproduction is prohibited.