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Tuesday, December 1, 2009

High Dynamic Range Done Naturally

Explore the basics of HDR to get details in shadows, highlights and everywhere in between

This Article Features Photo Zoom

Extreme HDR Step By Step
By Joseph Rossbach

1 You must have your camera locked down on a tripod so there’s no shift when you bracket your exposures.

2 Bracket a set of exposures to cover the dynamic range of the scene. Depending on the range of light, expose for full detail in the darkest shadows to the brightest highlights. I often set my camera for auto-bracketing and shoot anywhere from five to nine shots at +1 and -1 EV values. If your camera doesn’t have auto-exposure bracketing, then just do it the old-fashioned way by changing the shutter speed between each shot. Remember to keep the aperture constant throughout the sequence of bracketed images.

3 Once you have the images on your computer, you’ll need to create an HDR image and then tone-map the shot. The most popular and widely used software program for creating HDR images is Photomatix Pro, www.hdrsoft.com.

4 Once you’ve generated an HDR image, click on the Tone Mapping button. To go for the comic-book look,
you’ll use the Details Enhancer tab. Keep the Smoothing setting to low and use the Strength slider to change the intensity of the effect. I suggest you keep the Saturation slider set to no more than 50%. Bringing the Saturation slider up to high will produce overly garish results.

5 Once you’ve played with all the different tabs and settings, click on the Process button.

6 Now you’ll see the results of tone-mapping the image on the original HDR file. Save the image as a TIFF file.

7 These tone-mapped HDR files often are very low in contrast with no real shadows or highlights in the image. For the last step of the process, I recommend bringing the file into any postcapture editing software, like Adobe Photoshop or Lightroom, for finishing touches. You’ll most likely need to reintroduce Contrast and Clarity into the image as well as tweak the Saturation in selective channels for effect.

Schneider Grad ND Filter
Graduated ND Filters
By Joseph Rossbach

The first tool I reach for in my camera bag when I’m trying to balance the light in a scene is the grad ND filter, a rectangular filter that’s darker at the top and gradually fades to clear toward the middle of the filter. This is a great tool for balancing the uneven light of sunrise and sunset. I like to use the Singh-Ray 4x6 grad ND filters, which were developed with renowned nature photographer and OP columnist Galen Rowell.

These filters come in a soft or hard gradation, and the scene and, in particular, the area that transitions from light to dark will dictate which one I use. For anything with a clear unobstructed horizon, I’ll usually go for a hard-edged filter. If I’m shooting a scene that has objects or dappled light at the transition line, I go for the soft-edged filter to avoid producing uneven darkening in parts of the image. For me, the best way to use these filters is handheld. This gives me the flexibility to position the filter exactly where it needs to be in the scene without having to conform to a filter holder.

Hoya 4x Grad ND Filter
There are a few other benefits to handholding the grads. When using a hard-edged grad, it’s all too common to create a dark “grad line” where the filter meets the transition from light to dark in the scene. What I do to combat this is to move the filter slightly up and down during exposure, just like dodging and burning in the wet darkroom. This takes a bit of practice to get it right, and you need to make sure not to shake the camera while doing so or else you’ll come away with a blurry image.

If you’re having trouble figuring out where to place the transition line in the shot, consider using the depth-of-field preview button while moving the filter around. By stopping the lens down to your shooting aperture, it makes it much easier to see exactly where the transition line is being placed. Even better, if your camera has Live View, this can be a great tool for seeing the overall darkening of the scene as you place the grad filter in front of the lens.


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