Tuesday, February 2, 2016

Seize the Fleeting Light (Exposure)


Cameras have been around for so long—almost two centuries—and have become so common that we take them for granted. But how remarkable to capture light and create an image with it! We can preserve a fleeting moment, a scene we’ll never see again, a friend soon gone. Sometimes when I’m struggling with a difficult shot and feeling exasperated, I contemplate this miracle, trying to create the excitement that the early photographers experienced:
“I have seized the fleeting light and imprisoned it! I have forced the sun to paint pictures for me!” LJM Dagurre, ca. 1835
The camera at its simplest: light reflected by the tree passes through a small opening, and creates an inverted image on a surface (source). If the image is to be preserved, the surface must be light-sensitive.
As the camera evolved, the basic structure remained the same: a light-proof box with a small opening, a lens to bring the captured rays into sharp focus, and a light-sensitive surface (today's digital sensor) which is exposed just long enough to capture the image.
Modified from source.

• • •

In 1870, photographer William Henry Jackson traveled for three months through the southern part of Wyoming Territory, on an expedition led by geologist Ferdinand Vandeveer Hayden. He took on the order of 200 photos, using the popular medium of the day—wet plates. Their greater sensitivity allowed significantly shorter exposure times, but they were hardly convenient. For one thing, a field photographer had to carry a darkroom to prepare and process the plates!
Jackson’s photographic gear was transported in an ambulance (small wagon) and on a mule named “Hypo”—for sodium hyposulfite, the popular photographic fixer of the day (source).

In mid-August, Jackson and four others made several side trips into the Laramie Mountains. He took photos of the rocky range with its odd granite outcrops—described by Hayden in his 1871 report:
… the red feldspathic granites rise in thick picturesque ridges, fifty to one hundred feet high, like ruined walls, lending a peculiar as well as picturesque appearance to the landscape.”
Granite rocks, at foot of Laramie Peak; William Henry Jackson, 1870 (source).
Granite rocks, southern Laramie Mountains; 2016.
Upon reaching a suitable vantage point, Jackson would set up the camera and darkroom—actually a dark box. He cut a 6.5” x 8.5” glass plate, and cleaned it carefully. Kneeling before the darkroom, in a cloth-covered frame with a bag-like opening for his head and shoulders, he poured a thick syrupy (and combustible) liquid on the plate, tilted it in various directions to get an even coat, and let the emulsion dry just enough to stay in place. The wet plate was placed in a dark cover, and carried to the camera.

Before installing the wet plate, Jackson brought the image into focus. He removed the lens cap, casting an inverted image on a sheet of ground glass. After adjusting the distance between image and lens, he put the cap back on, and replaced the ground glass with the wet plate. Then he removed the lens cap and started counting.

Jackson needed enough light to reveal the details of the scene, but if he captured too much, the image would be washed out—overexposed. He took into consideration the brightness of the day, the light coming off the subject, the degree of detail desired, past experience and a sizable dose of intuition. An exposure on the order of five seconds often worked well for landscapes, but sometimes exposures were measured in minutes.

The exposed plate was put back in the dark cover, taken to the darkroom, and developed to reveal the captured image. It was fixed in a bath of hyposulfite, and examined to see if the exposure had been correct.
“The art of timing exposures was still so uncertain that one prayed every time the lens was uncapped, and no picture was a safe bet until the plate had been developed.” (from Jackson & Driggs 1929)
Granite ridges near the eastern base of Laramie Peak; William Henry Jackson, 1870 (source). Click on image to view the horse-drawn ambulance carrying photography gear.
The difficulties endured by Jackson and other early explorer-photographers seem onerous today. But their efforts were justified. Photographs were still novel and in great demand, especially given the time and place. Much of the American West was wild undeveloped country. Photos could show spectacular landscapes to people who would never be able to visit themselves ... miraculous!
Granite rocks, southern Laramie Mountains; 2016.
The Sherman granite is about 1.5 billion years old. It was intruded soon after a continental fragment collided with what was then the south coast of North America.

Like Jackson, I’ve made trips into the Laramie Mountains to take photos. And like Jackson, I have to be careful about the amount of light I seize. But there's no counting, no guessing, no waiting until the image is developed and fixed to see if the exposure was correct. It's so much easier with my digital camera—most of the time.

In Auto mode, I simply compose and press the shutter button halfway down. The camera quickly makes measurements, calculations and choices. Then I push the button the rest of the way to seize the light and create an image. Occasionally I change certain settings: smaller aperture for greater depth of field; or faster shutter speed for a moving subject. The camera adjusts other parameters to maintain a correct exposure.

As I know from experience, my camera usually makes the right choices. In fact, most of the time it performs far better than I could ever hope to! But not always. Some scenes defy its metering system—for example winter landscapes.
Vedauwoo Glen, Laramie Mountains.
The Laramie Mountains are cold and snowy in winter, but with lots of sunshine. This makes them appealing for photography outings, but also creates extreme contrast between snow and everything else, which can confuse the camera. When it compensates for bright snow, everything else is too dark. If darker areas dominate the scene, the snow turns out totally white.

I’ve tried three types of strategies for seizing the right amount of light: camera settings, post-processing, and choice of subject.

On my DSLR, I can use exposure compensation to adjust how much light is captured. A bright snowy scene seems to require +1 or even +2 to correctly expose darker areas. But sadly, the beautiful sparkly snow often gets washed out.
Camera’s exposure.
Exposure compensation of +1 revealed the aspen trunks, but made the snow-shadow pattern too bright.
Another option is to focus/meter on a darker part of the scene (button halfway down), and re-frame before shooting. But this often produces the same problematic results: dark subjects and/or washed out snow.

Unsatisfactory results can be adjusted to some degree in post-processing. In iPhoto, reducing Shadows sometimes makes dark areas more interesting without washing out the snow. A simpler alternative is conversion to monochrome—high contrast is often desirable in black-and-white photography.
Original.
Post-processed.

Original.
Post-processed.

Perhaps the easiest “solution” is to shoot scenes where high contrast is acceptable or even desirable—silhouettes, shadows and aspen trees for example. I like these kinds of scenes, especially in black-and-white.
High-contrast dog. Note ear as wind-sock.

Do you photograph snowy landscapes? What’s your strategy for seizing just the right amount of light?


Sources

Hayden, FV. 1871. Preliminary report of the United States Geological Survey of Wyoming and parts of contiguous territories. Washington, Govt. Print. Off. 

Hirsch, R. 2000. Seizing the light; a history of photography. McGraw-Hill.

Jackson, WH. 1870. Diary (typed transcript). William Henry Jackson Papers, New York Public Library.

Jackson, WH. 1874. Descriptive catalogue of the photographs of the United States Geological survey of the territories, for the years 1869 to 1873, inclusive. Washington, Govt. Print. Off. PDF (Biodiversity Heritage Library).

Jackson, WH, in collaboration with HR Driggs. 1929. The Pioneer Photographer; Rocky Mountain Adventures with a Camera. Yonkers-on-Hudson, NY: World Book Company.

Tissandier, G. 1877. A History and Handbook of Photography (ed. J. Thomson). NY: Scovill Manufacturing Company.

Tuesday, January 26, 2016

Escape to a Warmer Greener World


Last week I left home all bundled up, walked through cold blowing snow, opened a door, and entered the warm verdant stillness of a forest of fig, lipstick and butterfly trees. In the understory grew bromeliads, bamboos, orchids, and plants I remembered from our yard in California long ago. It was a magical transition!
Bird-of-paradise awakened childhood memories. Photo by Betsy Jo Moore.
Betsy and I spent several hours in the Williams Conservatory (University of Wyoming), intent on improving our camera skills. We didn’t look at all that many plants, waylaid as we were by technicalities. But it hardly mattered—there still was so much to see!

All around were splashes of bright colors. Betsy captured them in beautiful flower portraits.
Photo by Betsy Jo Moore.
Photo by Betsy Jo Moore.
Photo of Betsy Jo Moore.
Meanwhile, I fell down a rabbit-hole into a wonderland of leafy abstraction.

Several years ago I blogged about abstract photographyPlants in the Abstract. Things haven't changed; it's still just as fun and satisfying. The abstract photographer looks at plants in non-traditional ways, seeking things like pattern, line, form and texture. It’s a fascinating experience, full of discovery. Immerse yourself in it, and you can escape whatever reality you’re currently stuck in.
This is obviously a plant. But high-lighted curving lines feel like the subject to me.
There was no shortage of patterns, curves, details and arrangements to capture with my macro lens (and tripod). It’s astounding how much I don’t see when I look at a plant, preoccupied as I am by the whole subject and its larger parts.
Bromeliad leaves.

Cactus areoles.

I entered a miniature Enchanted Forest …
… atop a giant barrel cactus!

The umbrella sedges (Cyperus alternifolius) looked like the ones we had in our backyard as kids. It was here that I took my only flower photos.
Flower head shot with macro as telephoto (100 mm).
Many tiny flowers in a cluster of spikes.
By making close carefully-framed compositions, I came away with a greater appreciation for the plants than my eyes alone would have provided. Will this ever be possible without a camera?
How to look closely—one of life’s persistent questions.

My escape didn’t end when I left the Conservatory. At home, I discovered more details after downloading the photos. I cropped profusely, and played around with post-processing.

Sometimes converting to black-and-white got rid of distracting color.

It was fun to experiment, even to the point of creating surrealistic images from subjects that were quite real. I was reminded of one of Ann McKinnell's recent photo tips (#4): “Give yourself permission to play! Sometimes you just need to allow yourself to experiment with new subjects and techniques without the pressure of making good images.”