Plugged In: Highlights of shooting in low light

By Joe Kashi, for the Redoubt Reporter

Not every photo “adventure” ends so smoothly as the problem solved that we discussed last week. On occasion, some adventures only narrowly avert becoming misadventures.

That was the case a few weeks ago when I was asked to complete photographing the wedding reception of two close friends after the professional photographer was called away. I definitely was unprepared for that unexpected turn of events. I had planned to take a few snapshots at our table, but not much more. For that reason I went light, bringing only a single wide-angle prime lens, not a fast zoom and not even a spare battery or decent electronic flash.

The interior lighting was lovely and wonderfully romantic, but very dim. Luckily, I did have a good camera, a current model Olympus E-P5 with a relatively large Micro Four-Thirds sensor and an Olympus 17-mm f/1.8 lens. The E-P5 did reasonably well in low light due to its good sensor, excellent image-stabilization hardware and very bright lens.

Despite using a more-flexible, higher-quality RAW image file format, the pro’s larger-sensor, full-frame camera would have been easier to use without flash in the very dim lighting. If needed, their powerful electronic flash would more readily produce properly lit images that didn’t require as much post-processing later.

A bright, high-quality zoom lens would have been more versatile than the single-magnification prime lens that I brought in anticipation of making a few snapshots. Instead, I “zoomed” the old-fashioned way, with my feet, moving forward and backward as needed. I hadn’t brought the Olympus’ separate electronic viewfinder, either, so I had to rely on images shown on the rear LCD screen, not optimum for composing photos in dimly lit, rapidly evolving situations.

All turned out well in the end, but only after a great deal of extra computer time post-processing the images using Adobe Lightroom. Had I known that I would be called upon in that manner, how would I have prepared myself?

  • At a minimum, I would have brought my older Pentax K-5, an APS-C digital SLR camera renowned for its good low-light capabilities. I also would have brought the Tamron 17- to 50-mm f/2.8 zoom that I usually mount on the K-5. That lens is very sharp, and bright enough for dim-light photography.
  • I also would have brought my Sigma EF-350DGST external electronic flash unit designed for Pentax dSLR cameras. Variants of this same basic model are specifically adapted for other camera brands. Higher-end flash units, like this Sigma, are much smarter than the low-end electronic flash built into most cameras, metering the exposure actually reaching the camera’s sensor and then shutting off when correct exposure has occurred. The small flash units built into most cameras don’t have that capability. External flash units like this can also tilt to bounce their flash off the ceiling to produce a softer, more flattering look, and adjust the beam of their flash to fit the lens’ magnification. They can mount diffusers in front of the flash reflector for an even softer look. I didn’t have that high-end electronic flash unit with me, either. I had only the tiny, pop-up electronic flash built into the Olympus E-P5. Basically, I had to pound nails with a very small wrench. The process was tedious, but at least the final results were “pretty.”

Here’s what worked:

  • Knowing that a lot of later computer work would be required, I used low, ISO 200 to ISO 400, sensitivity settings despite the low light. I did so to preserve image detail, low noise and good dynamic range, all of which are important when later individually post-processing each image.
  • I relied on the very bright, f/1.8 lens and Olympus’ class-leading, five-axis, in-body image-stabilization hardware to produce sharp images at low ISO setting. That worked well with relatively static subjects, but not when there was a lot of movement, such as dancing.
  • Faster-moving scenes required not only using that tiny, built-in electronic flash, which usually has a range of a few feet but can at least stop action, but also higher ISO sensitivities. That required extra post-processing for best results. A lot of images will show some subject motion blur at slower shutter speeds, so take a lot of extra shots, discarding all but the best ones.
  • Shooting video required even higher ISO sensitivities. I just set my video mode options to “P” program mode and an auto-ISO setting that did not exceed ISO 1,600. Fortunately, that worked fairly well without a lot of fussing. Electronic flash, of course, is useless in video mode, so it was available light or nothing. Luckily, the pixel binning used to reduce a large sensor readout to 1,920-pixel-wide HD video also reduces high-ISO noise.

Small, undiffused, electronic flash units tend to produce out-of-camera images that look harsh at first glance. Using Lightroom, I was able to get nice results with the following basic method:

  • Use the white-balance-adjustment eye-dropper on a known-white object, such as the bride’s dress, to compensate for a bluish color cast. Then, use the white-balance, blue-yellow slider as needed to warm up the overall cooler balance to test. In these situations, a warmer color balance is usually preferred.
  • Fix any chromatic aberration.
  • As a starting point, use Lightroom’s “Auto” exposure setting to make an initial automatic adjustment to shadow and highlight areas, reducing highlight adjustment and boosting the inevitably dark shadows. This works well only if you are using an RAW format image file that has a lot of dynamic range.
  • Adjust clarity to provide the desired degree of “pop” separating the foreground from the background.
  • Finally, adjust overall contrast, cropping, noise reduction and sharpness to taste. So, in the end, all went well with a bit of extra post-processing.

Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University Many of his technology and photography articles can be accessed through his website, http://www.kashilaw.com.

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