Hdr examples

 

Here are a couple of hdr examples which do not look the way most hdr images do. I used the hdr image as a starting point for creating a more expressive image, and chose to lose information in both light and dark areas to serve that purpose. Hdr images are useful here for allowing a wider range of exploration.

img_7271_69_70-bw-colorized-v1b.jpg

img_6938_6_7_tonemapped-cropped-bw-colorized-v2b.jpg

img_6938_6_7_tonemapped-cropped3-bw-reversed.jpg

img_6938_6_7_tonemapped-cropped4-bw-reversed.jpg

img_6938_6_7_tonemapped-cropped2-bw-reversed.jpg

High dynamic range photography: a simple how-to

 

I haven’t used my film SLR camera for several years, and one of the reasons was my frequent disappointment with the limited dynamic range of the photos. Very often, details in the light or shadow areas were lost, merging into a flat white or black hole in the picture. The only remedy was to get out my camera only in low contrast conditions such as overcast weather, or just before sunrise and after sunset. Even then, the shadows or highlights would often lose detail.

With digital SLRs, it is now easy to take high dynamic range photos, provided the subject doesn’t move too much. Since I got my first digital SLR a couple of weeks back, I have experimented some with HDR and am surprised of how easy it is to get decent results.

The hdr workflow is simple:

  1. Take three or more differently exposed photos of the same scene, respectively exposed normally and for details in highlights and shadows
  2. Import them to Photomatix or Photoshop CS2 or other hdr software and output the result through tone mapping
  3. Edit in Gimp, Photoshop or other image editing software

Here are a few more details:

  1. Taking the source images
    • Since the source images are combined into one, it works better with subjects that don’t move much. Some movement within the scene is usually OK.
    • It is helpful to use a tripod, but handheld works fine as well.
    • The easiest is to set the camera to auto-bracket the exposure, keeping the aperture constant and changing only the exposure time.
    • Feel free to break the old rules and choose high-contrast images: shoot into the sunset, include a bright light in the scene, or a backlit subject.
  2. HDR processing
    • Photomatix is free for most of its functions, and about $100 for a full featured version. Photoshop CS2 also has an HDR function, but is more expensive.
    • When importing, remember that the resulting image has a tonal range far greater than what your computer screen can deal with, so it may well look awful on the screen. Don’t worry. It is supposed to.
    • Experiment with the tonal mapping to translate the raw hdr image into something that can be shown on a screen or printed on paper. Try several settings and choose the best one. Save it as a 16 bit tiff file.
  3. Final editing
    • Import the tone mapped image into your image editing software. GIMP is a good choice since it is free (open source) and does most of what Photoshop does.
    • Edit as you would any other image. Although you have a wide dynamic range in your image, don’t be locked into the idea of having to preserve all the detail in the highlights and shadows. Some images work better when the contrast is a little higher, and you have more freedom to play with this when your source image has a high dynamic range.

Here is a scene that normally has too high contrast: a wall in the shade with a bright sky in the background.

I took three handheld exposures of this Portland street scene, using the auto-bracketing feature on my camera. The first image is normally exposed, and the two following under- and over-exposed two stops. (Three exposures and two stops either direction is the maximum on my camera, which is OK but a little limited for hdr photography. Five exposures and three or four stops cover a greater range and may be needed for extremely high contrast scenes.)

img_7101.JPG
Normally exposed image with good details in the mid range.
img_7102.JPG
Underexposed image, with details in the sky and clouds.

img_7103.JPG
Overexposed image with information in the darkest shade areas.

I then imported them to Photomatix, and got this result on the screen. Moving the cursor over the image shows the area details in a separate window. (I have included two examples, one of details over the door and one in the clouds.) Photomatix automatically align the source images, and does a good job even with handheld exposures.

img-7101_2_3-screen-image.jpg
The hdr combination of the three source images, with information in the lightest and darkest areas.

And tone mapped it using the tone compressor option, and experimenting with the different settings to include as much information in the final image as possible.

img_7103_1_2_tonemapped.jpg
The tone mapped output, ready for final editing.

The colors on the tone mapped image can get a little weird (it depends on the settings you use), so for the final editing, I like to keep the normally exposed source image up on the screen as a color reference. I used level, curves, color balance and hue adjustment layers for this image, and also masks to treat the sky slightly differently from the rest of the image. The final editing in Photoshop gave this result:

img_7103_1_2_tonemapped-v1.jpg
The final image, after editing in Photoshop. I went for a vivid but still relatively realistic look.

If you have questions, I’ll be happy to answer to the best of my (very limited) ability. Just post them below.

Here are some resources I found helpful when I first explored it:

hdr as an anology

 

230134559_f410727679_b_d.jpg

photo by Automatt

466742010_e9cb94e42c_o_d.jpg

photo by John in Japan

High Dynamic Range imaging is a way of extending the tonal range of a photo, or said another way, to include details in both the highlights and the shadows. It has been used in film for a while, and is now also increasingly used among digital photographers, where three or five or more photos of the same scene, each exposed differently, are combined into a single image with an extended tonal range.

A HDR image itself has a tonal range far beyond what any screen or any paper can represent, so it needs to be compressed and processed down into something that can be represented in these forms. It is similar to a “digital negative” that needs to be developed, and there an infinite number of ways of doing this, and no one set way that works in all situations. The processing is different each time, and tailored for the specific image and its purpose.

This is a good analogy for talking about Big Mind, about finding ourselves as this awakeness and its content, inherently absent of an I with an Other.

Big Mind is beyond what can be touched by words, as a HDR image is far beyond what can be accurately represented on screen or in print. And in each case, there is an infinite number of ways to translate it down to something that can be expressed. There is an infinite number of ways to process a HDR negative, and an infinite number of ways to put an immediate experience of/in Big Mind into words. And in each case, how we do it depends on what we want to express – a particular image, an aspect of Big Mind, and the circumstances – what it is going to be used for and what purpose it is intended to serve.

Any analogy breaks down somewhere, which is why it is only an analogy. And this one breaks most clearly down in that a HDR negative and finished processed image are not different in type, only in tonal range, and that Big Mind is inherently free from anything that can be expressed in words, even as it is (attempted) expressed in words. Big Mind is beyond and includes any polarities, and words only works within polarities.

In the case of HDRs, it is a difference in degree, and in the case of Big Mind and words, a difference in type.