Joe and Mary Ann McDonald's

Wildlife Photography

November 2005

Tip of the Month

Avoiding Star-trails with the Northern Lights

This tip is courtesy of a professional photographer friend of mine, LeRoy Zimmerman, of Fairbanks, Alaska, who specializes in shooting 35mm film panoramas and who does wonderful work with the Northern Lights. The Northern Lights, or aurora borealis, is a phenomenon linked with the sun's activity and solar flares, where electromagnetic radiation reacts with the atmosphere at both the northern and southern end of our planet, creating the dancing, colorful light shows that make magic in an arctic night. I seen them a few times, but either because of our schedule, our shooting conditions, or their briefness, I hadn't been able to photograph them. That changed, recently, on our visit to Churchill, Manitoba to photograph polar bears where the weather was absolutely, completely, unnaturally mild, which allowed us to be out for as long as we needed, at night, without feeling any cold. It was a wonderful opportunity to shoot the Lights, but, unfortunately, this celestrial show only appeared on one of our many clear nights.

One past difficulty in photographing the Northern Lights was the ISO required -- 400 or so, which I rarely carried when I shot film. Now, with digital, this wasn't an issue and for the northern lights Mary and I cranked our ISO up to 400, 800, and even 1000, for exposures ranging from 8 to about 13 seconds. For the first part of this shoot I had to mount my camera upon a beanbag -- we didn't unpack our camera plates yet, since this was the first night of the trip! Luckily, though, Mary drove back to town -- we had driven a short distance out of town to avoid distracting town lights -- and retrieved our plates, so some of our first shots had blurred stars because of camera movement.

However, the trouble with shooting any lengthy time exposures involving the sky is that the stars will streak during the exposure, as the earth rotates, creating the impression that the stars are moving across the sky. The longer the lens focal length, the more that movement will be evident. LeRoy's suggestion is to divide your focal length into 800 (or, to really be safe, 500), and the resulting number is the length of time the shutter can be open before a star trail is evident. Thus, if you were shooting something with a 400mm lens, you'd have only 2 seconds before streaking would occur. Who'd shoot with that long a lens? Well, one of the folks on the polar bear trip was using a Fuji pano with a 300mm lens, so his exposures were limited to 3 seconds or so. For Mary and I, who were using 17-35 or 28-300mm lenses, all at the short end, shutter speeds of 10 seconds or so were not a problem.


Our Past Photo Tips of the Month:


ProShow Gold
Digital Slide Program


 DIGITAL- Digital Birding

 DIGITAL -Shoot for the Future

 DIGITAL-Shoot for the Future, Part II

 Capture 1's Most Useful Features

maximizing depth of field digitally

  Backing Up Your Digital Files - you'll need more than you think

 DIGITAL Photographing scenes with extreme exposure values

 NPN- Nature Photography Network - a digital forum for nature photography

 Digital Pro Image Management Software

 Watch Your Backgrounds
The potential of composites or shooting in RAW format

 A Great Website for Information - the Singapore Nature Photography Society

 Save Your Equipment from Crashing!

 The L-Bracket, the ultimate camera bumper

At the Pulse of Life
by Fritz Polking

 Carry Your Gear!

 Shooting in Inclement Weather

 Carry-on Luggage for small commuter flights

 Ask Questions
Before You Go

 Seize the Moment!

Geared Focusing Rail for Macro Work 

 Protecting your long lens from SAND, the pleasures of beach photography

 How do we protect our gear from dust, and carry our gear when on safari

 The Ultimate Flash Bracket
Padding Your Wimberley
Tripod Head

  Specular highlights and the flashing frog
 Using TTL flash with Hummingbirds  Testing your Flash's Aim
Maximum Depth of Field and Hyperfocal Distance - they're not the same thing!  If you see it, it's too late -- a lesson in anticipation  How do you shoot the Moon?
  Low level tripod work  A great depth of field guide  Wimberley 400 and 600mm IS plate

 Sigma's 120-300mm F2.8 APO HSM zoom lens

 Using The Wimberley Gimbal head with a camera body

 Sigma's 120-300 f2.8 APO
zoom telephoto lens

 Custom Function 4-1 for Nikon and Canon shooters

 Sighting in a very, very long lens
 The Nature Photography Network - a super website for images and information
  Take a Workshop First   Luck, what is it?  Don't take in baby wild animals

  Airline Carry-On Luggage -Let your concerns be heard!

 Disconnect -- travel precautions

Photograph America Newsletter
 Wildlife Portraiture

 Obey the Rules
The Ti Chi Stalk
Photographing Critically Endangered Sites Bushnell Night Vision Optics  Adobe Photoshop 7 for $300

 The Sibley Bird Guides

 Removing Cactus Spines

 Drying out boots with newspaper

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