Three years ago in this feature, I published one of my son's wild bobcat photos beside a captive shot of my own. I described his as the better image, possessing the integrity of a wild moment, despite the fact that my portrait on Fuji Velvia lit with fill flash was sharper, closer, and more dramatic.
Tony's first publishable bobcat photo was the result of 23 attempts in the hills of Marin County. Since then, he has continued his quest to observe and photograph predators in wild areas near his home. His latest bobcat images eclipse not only both of our previous efforts but also the well-meant advice of film manufacturers and photographic writers, including his father. Beforehand, I'd have sternly advised him not to ever push ISO 100 films 3.5 stops to an exposure index (EI) of 1200.
Real life does not always follow armchair logic. When Tony spotted the cat stalking a pocket gopher in very low light, he was riding his mountain bike with a 400mm f5.6 lens in his pack and Kodak Lumiere 100 in his camera. He had no better option than to shoot at a high enough speed to stop the action and have the film push-processed accordingly. He kept his shutter speed at 1/125 even though he was a full 3.5 stops underexposed. Thus, these photographs were taken at EI 1200 on ISO 100 film. Had Tony not pushed the film so far, he would have failed to capture the cat in the act of pouncing and carrying the pocket gopher away. His results would have been too dark at a lower film speed or too blurry at a lower shutter speed.
On the same day that Tony photographed the bobcat and called to ask for processing advice, I had already been talking about push processing with Sam Hoffman, owner of The New Lab in San Francisco. Myexperience had been that one- and two-stop push-processes by The New Lab had produced very accurate exposures at the expected EI ratings. For a one-stop push of ISO 100 film, I set my film speed at 200; if the lighting or the subject was contrasty, I sometimes set my speed at 240 to hold detail in the highlights, which burn out more quickly with push processing. Keep in mind that when I shoot ISO 100 Kodak films without push-processing, I also prefer to set my camera at EI 125 if the lighting or the subject is contrasty, as in most sunlit outdoor scenes.
Sam described how his lab uses a densitometer to create logarithmic increases in development to precisely achieve the indicated push. Using another lab, George Lepp gets other results by setting his film speed to EI 160 for a one-stop push. The difference comes from labs and personal preference. You have to make your own tests. Shadows, of course, always appear a bit darker with push processing due to contrast build-up.
Tony talked it over with the lab and decided to try a 3.5-stop push to ISO 1200. THe results have surprisingly little grain for ISO 1200 as well as perfect exposure. The grain appears considerably tighter than that of a straight ISO 800 color slide film and about the same as a straight ISO 400 slide film. By following and exceeding my advice to push ISO 100 film in low light rather than use a faster film, Tony's results benefit from the contrast build-up and warm color shift associated with push processing.
Using a film designed by the manufacturer to have minimal corrections for pushing can actually improve a telephoto taken in flat light. I regularly push ISO 50 Fujichrome Velvia one stop for aerials and flat lighting to get snappier images. Had Tony been shooting in direct sun or mottled light, his results at ISO 1200 would have been ghastly. Shadows would have blocked up into a murky brown with no true blacks, while highlights would have completely burned out.
These bobcat images succeed at ISO 1200 only because there were no shadows and no highlights much brighter than the cat. Though situations like this aren't exactly common in nature, they do coincide with most of the times a wildlife photographer feels the need to use very high film speeds with long lenses in low light.
Much of the credit for the proper exposure and the clarity of these images pushed 3.5 stops is due to fine processing by The New Lab (800) 526-3165. When I've had film push-processed elsewhere while on the road, I've all too often had objectionable color shifts and dark slides due to variations in procedures and chemistry. It pays off in the long run to shoot test rolls and stick with a lab that gives you consistently fine results.
I recently processed extensive tests on Kodak's new Ektachrome 200 at The New Lab and found that the film indeed performs as well as Kodak describes it, except for being about a half-stop dark with pushes of two stops or more which is not the case with other films I normally push. Although it has significantly more grain than a 100-speed film to begin with, it pushes with less color shift, less contrast build up, and less visible grain increase at ISO 800 and ISO 1600 than with ISO 100 films.
When shooting wildlife in low light at ISO 200 or 400, I strongly prefer pushing E100S or Provia, but for extremely high-speed shooting with normal lenses in average lighting, I would definitely choose the new Ektachrome 200 over having to push a 100 speed film a full stop further, or over far more grainy ISO 800 films. But for the rare situation Tony caught with this bobcat, I wouldn't change a thing, except to use 20/20 hindsight to bring a faster lens.