Monthly Archives: June 2007

Rose Moon Rising

Full summer moons toward the end of June are sometimes called “rose moons,” and this one lives up to the name.

Last night, Phyllis and I parked the kids at a pizza and movie party given at Nicky and Mathew’s pre-school. Then we picked up sandwiches and headed for the Marin Headlands side of the Golden Gate.

The fog coming and going was beautiful, and the rose moon rising was icing on the cake (to badly mix my metaphors). For me, this was a bus person’s holiday, to throw more metaphors into the stew. But it was great having Phyllis along, and she enjoyed the show of light and air in the Golden Gate. And, as Phyllis said, she enjoyed the fog horns tuned to a fifth interval apart on a diatonic scale, pleasing to Western ears.

Posted in Landscape, Photography, San Francisco Area

Hidden Beach

Mark and I hiked out to Arch Rock. It was a crap shoot whether we’d be fogged out, but emerging from the four-mile tunnel of forest the sunset was clear.

Last time I’d hiked out to Arch Rock, by the time I got out to the ocean it was too dark to see more than the general contours of the landscape. This time we were earlier and the sky was bright with moon. By the light of the setting sun and almost-full moon I was able to make my way down a little path towards a hidden beach.

The path switch-backed down a small slot canyon to the banks of a creek. Making my way across a couple of fairly easy rock faces I made my way down beside the creek to where the splash of water met the ocean.

On this small, sandy spot I set up my tripod. In one direction, the high tide created a whirlpool beneath the arch in Arch Rock (photo below, captured at 2.5 seconds exposure, see my O’Reilly blog post for some technical discussion of the exposure and post-processing technique).

In the other direction (photo above, captured at 1/50 of a second), the moon shown through the end of the canyon and on the small hidden beach, also lit by the setting sun.

Through the Arch

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Posted in Landscape, Photography, Point Reyes

Moon Shadow of Half Dome

I took this photograph during my vigil on the top of Half Dome at about 11:20PM. It’s a 569 second exposure at f/4 and ISO 100. The view is facing pretty much due east. You can see the recognizable profile of Half Dome in the moon shadow in the foreground of the photo.

For more of the story behind this image, see Snakes and Ladders, Half Dome by Starlight, and Midnight Rambles.

Posted in Digital Night, Landscape, Photography

Exposing the Night Landscape

Photographers often ask me how to get the right exposure with night landscapes. It’s a tricky topic. My experience is that the light meter in my dSLR is pretty much worthless for anything that is dark enough to need an exposure of longer than about 15 seconds at ISO 100. This can be OK for night cityscapes, which typically come in at between 15-30 seconds at ISO 100. But it does mean that the internal light meter is useless in darker landscape situations.

Once exposure times get beyond this city night range, I switch to manual exposure mode, and use the feedback from the camera’s LCD to see how I am doing. The problem with this is that you can’t always tell with night exposures from the LCD whether you’ve exposed properly, or whether you got anything at all. Also, it can be very hard to switch between a bright LCD panel and the almost total darkness of the true night landscape. You want to get your eyes accustomed to the darkness, and checking out the LCD breaks this concentration.

Midnight Rambles

View this image larger. Read the back story featuring this image.

So if the camera’s metering is no help, and the LCD review only partially useful, what gives? The answers tend to be trial and error and experience, but there are some tricks that help.

First, you want to start exposing before it gets completely dark. This gives you a feeling for where the light is trending as the night deepens.

Next, consider how long an exposure you want to make. The difference between longer and shorter exposures at night tends to be the impact on lights in motion (think of stars). For example, an exposure in the 15-30 minute range will render attractive curved star trails, while an exposure of under 3 minutes duration will mostly render stars as pinpoint light sources. (This story has an example of more or less the same scene rendered each way.)

You don’t get many cracks at 15-30 minute exposures, at least not without direct current access. My experience is that a 25 minute exposure, processed for noise reduction, will drain a fully charged battery to nothing (besides taking about 40 minutes in toto).

So the best tactic is to get the exposure right at a high ISO. I find that 3.5 minutes at ISO 640 and f/4 is about right for a night lightscape lit only by starlight. (You might want to do seat-of-the-pants adjustments for light sources other than stars such as the moon, residual sunset, or ambient people light.) If you fire off a shot at ISO 640 and 3.5 minutes and find it is roughly right, you can then calculate the equivalent at ISO 100 by mutliplying the exposure time by 6.4. This gives an exposure time of 22.5 minutes. Plop in a fresh battery, and expose away, with some confidence that your one shot will be close enough (as in the 22.5 minute exposure of Half Dome and Tenaya Canyon with star trails that illustrates this story).

Posted in Digital Night, Landscape, Photography

Scanning the Iris

My Dad says he told a group of his friends that he just bought a $25,000 computer. Understand that these friends were a bunch of computer scientists. Everyone thought my father had bought some really macho heavy digital iron. Completing the punch line, my dear father said, describing his Toyota Prius, “and it even came with a steering wheel and four tires.”

Similarly, a digital camera like a dSLR is a special-purpose computer. It happens to come with a lens (most of time) and a scanner (the sensor).

Iris Scan 2

If digital photography is to live up to its full potential as a brave new medium, and not remain stuck as the bastard child of silver-halide photography, then we need to look at capturing differently. Why not start with a scan using a flatbed rather than a scan from a camera?

I created these Iris images (above and below) using an inexpensive desktop scanner.

Related story: Myths, Metaphors, and Digital Photography.

Iris Scan 1

Posted in Bemusements, Photography

Snakes and Ladders

Back down from Glacier Point in the early predawn hours, I caught a few hours sleep and then started up the trail for Half Dome. I knew I wanted to photograph the night view from the top of Half Dome. But my plans were not quite clear. I thought I might come down after photographing and catch Nevada and Vernal Falls by star light.

On the other hand, once darkness fell I might be stuck on Half Dome for the night. So I brought some warm clothes, some power bars, and my head lamp in my camera backpack.

A funny feeling: all the abstract, advance planning for this moment of starting out. The hordes of tourists diminish as I head upstream, up the Merced River. They’re thick to the Vernal Falls bridge, and pretty thick up the Mist Trail. Muggles with cell phones and iPods in the wilderness. What’s the point of being in the wilderness if you can’t break the electronic umbilicus?

There are fewer people above Vernal Falls and on up to Nevada Falls. Above Nevada Falls the human flood dimishes to a trickle along the Merced in Little Yosemite. This is a tough trail, tough enough to discourage anyone out of shape or not really motivated.

By the banks of the Merced, I strip off my hiking boots and shirt, and cool off in the river. I drain my water bottle, and pump a new bottle for the treck up to Half Dome, and maybe so I can have water overnight.

I just finish pumping when I look around and see a few feet from me, slithering over my hat, and between me and my camera bag, a rattlesnake. The snake is about three feet long, handsome, with viper head, beady eye, and rattles. We look at each other. Then he waves his tail and slowly coils into the underbrush.

Partially fueled with adrenaline from my snake encounter, I head up the dusty switchbacks. This is a long, steady climb. At last I reach the top of the ridge. Turning back east on the ridge, a combination of stone staircase and glaciated granite shelves head up the dome that leads along to Half Dome. At last I reach the bottom of the notorious cable ladder up Half Dome.

This ladder goes up roughly five hundred feet. It’s constructed using metal poles stuck into the rock every twenty feet or so apart. A wood cross piece goes at the bottom at each set of poles, and metal cables go through holes in the top of each pole, roughly at armpit height if one were perpendicular to the rock face of Half Dome. The trick to climbing the thing is to use your upper body strength to wedge yourself as far out from the cliff as possible, so that you can more or less walk up if you’ve balanced it right. Worth noting: the climb isn’t made any easier if you are carrying twenty-odd pounds of camera and tripod gear.

The sun is setting. Looking up the cable ladder, it’s darn clear to me that once on top, and after the sun had gone down, I’ll be on top as long as night lasts. No way am I coming down that thing in the dark. Taking a deep breath, I head up (stay tuned for my adventures on the top).

The photo that illustrates this story shows the east face of Half Dome and the ladder lit by the rising sun. I had just safely come down the ladder. Standing looking back, I met the first hikers of the day coming up from the valley (you can make it up shortly after sunrise if you leave the valley about midnight).

They told me about Hirofumi Nohara, who had slipped off the Half Dome ladder a few days before, and bounced down about 300 feet and over the side towards Yosemite Valley. Nohara is one of three people who died on the Half Dome ladder in the last year.

I feel really bad about Nohara’s accident, although I’m glad I didn’t learn about it until I was off Half Dome.

It’s easy to see how the accident could have happened. Although I had Half Dome to myself, on summer weekends the cable ladders are solid lines of people. It’s an easy guess that many people going up Half Dome don’t have proper gear, particularly good boots.

You also have to figure that part of the point of wilderness travel is that it is inherently somewhat dangerous. For example, see this story about hiker Hyundo Ahn, missing in the Sierras a few years back. No one knows what happened to him.

At its best, a good hike is part exercise and part mystical experience. And the mystical experience cannot be, as C.S. Lewis put it, a “tame lion” or it becomes inauthentic.

I really don’t know how the Park Service is going to resolve this one, although I’d imagine they aren’t going to allow such a dangerous situation to persist indefinitely. Still, if we lose the ability to climb Half Dome on our own terms, we’ve lost something important. Hazards such as the Half Dome cable ladder, and even venomous snakes, are part of the reason we visit the wilderness.

Related stories: Half Dome by Starlight; Midnight Rambles.

Posted in Hiking, Landscape, Photography, Yosemite

Half Dome by Starlight

Last week I went to Yosemite. As my kids might say, this was an “opposites day” venture: my plan was to photograph at night and sleep during the day.

More or less, my plan worked out with an unexpected fringe benefit: even at the height of the summer season I didn’t see too many people.

My most important goal: to photograph the night time vista from the top of Half Dome.

My trip was carefully planned to coincide with the summer solstice to give me the most daylight possible to get into position. Of course, the downside to the long days was that I needed to stay up late to make it into true night.

A typical wilderness hike for me involves a trail and a route, but no set-in-stone destination at any particular time. This trip was different, more like a targeted insertion. I had to plan very carefully to be a certain places (some harder to get to than others) at specific times.

On Monday afternoon I got to Yosemite Valley. I picked up a pizza to go and headed up the Glacier Point road. Sunset saw me at the fissures hard by Taft Point. These fissues are narrow cracks that fall straight down into the valley.

In the gathering dark I hiked back to my car and headed for Glacier Point. Down below, the lights from Curry Village, the Ahwanee, and campgrounds looked like either a shanty town, or a not-so-small civilization. Camera on tripod I pointed at Half Dome, lit by stars and ambient light. I exposed the image above at about 10:30PM at 2.5 minutes, ISO 640, and f/4. An hour later I exposed the image below for 15.5 minutes at ISO 100 and f/7.1.

You can see the impact of the differing shutter speeds in the rendition of the stars. At 2.5 minutes, they still seem to be points of light. At 15 minutes, the stars are curved paths of light in the sky.

From my dark perch on Glacier Point I looked across at Half Dome, knowing that if all went according to plan the next night would find me photographing from the top.

Half Dome by Starlight 2

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Related story: Midnight Rambles.

Posted in Digital Night, Landscape, Photography, Yosemite

Midnight Rambles

I took this photo of the view down Tenaya Canyon towards Half Dome shortly before midnight on June 21. I was standing on a granite rock “platform” about 1/2 a mile from the parking lot at Olmsted Point along the Tioga Pass road. I exposed the image for 1348 seconds, or 22.5 minutes. You can see the Tenaya watershed, Mt Sunrise, and Half Dome (towards the right of the photo) lit by ambient starlight and the setting crescent moon. In the background of the photo, you can see the pale remains of sunset and also light from the California valley cities like Merced and Fresno (some of this light is also on Half Dome).

Two nights before I spent a lonely and awesome night time vigil on Half Dome itself photographing the stars and the landscape. As I waited during my midnight rambles while this exposure was being captured, and then being processed, I could hear the occassional call of an owl and a coyote. I could also look out to Half Dome and see my platform in the sky.

Related stories: Creature of the Night; Digital Darkness; On Night Photography.

Visit Digital Night by Harold Davis. Check out the view of Half Dome from Olmsted Point in daylight (scroll to the bottom of the linked story).

Posted in Digital Night, Landscape, Photography, Yosemite

Myths, Metaphors, and Digital Photography

If you grant my premise that digital photography is an entirely new medium of expression, then you have to wonder about the prevalence of metaphors that use the techniques of analog photography. In Photoshop, we use the Dodge and Burn tools. We “cross process” using Nik’s excellent library of Photoshop filters (among other digital “cross processing” techniques). We produce versions of our images from our RAW captures that are “like the prints made from film negatives.” The myths and metaphors imported from film are useful shared vocabulary, but none of these analog-to-digital metaphors are really quite right.

Wood between the Worlds

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A metaphor is an implicit comparison of one thing to something else: “my love is a red, red rose”. A simile, of course, is a kind of metaphor that makes the comparison explicit using “like” or “as”: “my love is as beautiful as a red, red rose.”

Confusion occurs when metaphors (or similes) are confused with facts. In no way are the metaphors of analog photography exactly analagous to the digital concepts and techniques described.

The Photoshop Dodge and Burn tools operate on pixels, not on emulsion-coated paper, and are not even the best way to achieve the results of lightening or darkening areas of an image. (You are much better off using selective layer masking, the Paintbrush tool, and blending modes to achieve this result.)

In analog terms, “cross processing” meant dunking film or paper in chemistry that was not intended. Nik carries this metaphor quite a distance. Its cross-process filters let you choose either C41 to E6, or E6 to C41 (using the names for Kodacolor and Ektachrome processing). You can also fine tune these filters in a variety of ways. But obviously you are not cross processing. At best, you have simulated cross processing with these Photoshop filters.

It’s true that I create many versions of my photos starting with a single RAW capture. For example, I might produce an RGB version for screen display, a CMYK version for publication, a sized CMYK version for running through my RIP software and making a physical print, a JPEG version for web display, and a light JPEG version that looks good on Flickr (Flickr runs a filter that makes some images look artificially darker), and so on. But these pixel-to-pixel conversions don’t really compare to the process of analog print making except in the sense that you are changing one thing (the negative or RAW capture) into another (the print or the converted file). Print making still requires output on paper.

So what’s to make of all this? Metaphors are good because they help communicate tough concepts. But they can also shackle us to think in a manner that doesn’t apply to new technologies and situations. Is there a good reason that new-fangled digital SLRs look pretty much like old-fashioned analog SLRs, or is this form-factor just what we are used to, and an example of metaphor gone awry? What will the digital generation that comes of age without understanding the analog terminology do with these dubious metaphors, and where will they go?

Night Shore 2

View this image larger. Read the back story featuring this image.

Myths can be something that is widely believed, but false. A myth can also be an important legend about how something was created. When myth is used in the second sense, the myth can even be true (at least in part). Myths are stories, and they are also metaphors.

The myths of analog photography include the patience required to coat fragile glass plates with emulsion, and to make exposures of long duration under field conditions. Ansel Adams is said to have carted his view camera up and down the Sierras on the back of a mule. These are stories of a forgotten world, and it’s hard to even remember the endurance it required to be a serious photographer.

When the last master silver halide print has been made, what myths will digital photographers have to compare with the heroic traditions of analog photography? Will the new mythology be about photography, or about processing pixels?

By learning to see the world digitally, by making long night exposures from a cliff high above the ocean, by experimenting with different ways to achieve digital capture and to process the captures, I like to think I am contributing to the new mythology of digital.

Posted in Photography, Writing

Golden Gate in Summer

A great bank of fog has covered the Bay area, so it’s a little hard to remember that this past week was summer. It was hot for around here, at least 85 degrees in Berkeley.

On Wednesday, Julian (shown below) had no school, and I took him out to Point Reyes where it was much cooler. We hiked down to Marshall Beach, built a sand castle, hiked back up, then drove over to Drakes Beach and climbed up the bluffs.

Julian above Drakes Beach

Julian was really respectful of the drop to the beach below. He said, “Dad, if someone fell off, they would die, right?”

Right. Good to hear caution from the boy who lived.

We drove back to Berkeley and took a swim at Julian’s grandparents.

By now it was late and Julian was very ready for dinner and bed. But the sun had set and turned the world pink with the haze of summer. I drove up to the parking lot beside the Lawrence Hall of Science, pulled out my tripod, and snapped this twenty-five second time exposure of the Golden Gate in summer.

Dear reader: I’m off this week to Yosemite to photograph digital night in the mountains, so most likely no blog stories until I get back.

Posted in Landscape, Photography, San Francisco Area

Beauty in the Belly of the Beast

This is a thirty second time exposure from the top of Mission Peak. It is looking down the slopes of Mission Peak across Fremont and the San Francisco Bay straight at Palo Alto and Mountain View. You can see the same clouds in an earlier exposure from the same series, focused to the south on San Jose.

If Silicon Valley is the beast, then this is an image of the belly of the beast. (Mission Peak has also been described as a beast, meaning that it is a tough hike.)

I’m ambivalent about Silicon Valley. On the one hand, I have to admire the gusto and inventivity that has sprung from the Silicon Valleys of the world. On the other hand I’ve spent a bit too much of my life working on pointless projects with bloated code and following irrational change control procedures.

You also have to admit there is something ugly about a culture that turns ranch land to a car culture wasteland of high-tech industrial parks and McMansions.

But I rant. I rave! The beast is indeed ugly, but it has beauty too. There’s beauty in the belly of the beast. And that’s what this photo means to me.

Related stories: Improv on Mission Peak; Above the Urban Sprawl; Mount Tamalpais from Mission Peak; Do You Know the Way?.

Posted in Digital Night, Landscape, Photography, San Francisco Area

Digital Night Website

It all started when I pointed my digital camera into the void of night and was surprised by the results. In apparent darkness, there’s plenty of “light” we cannot see that is picked up by digital sensors. The digital night landscape is very colorful indeed. Since this discovery, I have haunted dark and wild landscapes at night…[Read more].

My new website, Digital Night by Harold Davis,, features photographs taken in the night. I also write about the techniques and human aspects of digital night photography.

Sausalito at Twilight

Read the back story featuring this image.

Posted in Digital Night, Photography, Writing

Bokeh and the Zen of Blur

The term bokeh is used to refer to blurring in a photograph. Good bokeh is smooth and pleasing, whereas bad bokeh produces a jagged and discordant effect. This may sound subjective, but pretty quickly you can get to recognize excellent bokeh when you see it in a photo. And the effort of doing so will help you improve your photography.

Bokeh generally refers to background blur rather than foreground blur, because background blur tends to be far more important than foreground blur in most compositions. The photo of the California poppy in the wind (below) is an exception to this rule.

Almost everyone can recognize sharpness of an entire composition as effective. Realistically, this can only happen in limited situations. For example, all elements of a photograph must be in focus (this happens in landscape photos at infinity) and everything must be still enough so there is no motion blur.

The way of bokeh is to recognize that almost all photographs have some blurring and out-of-focus elements. Rather than deprecating, the zen of blur is to embrace. If you must have blur, why not make your bokeh the best it can be?

Taking the zen of bokeh one step further, can you conceive of photos that are about blurring rather than sharpness?


View this photograph larger. Read the back story featuring this image.

Bokeh comes from the Japanese word boke (ぼけ), meaning blur. The terminology may also be derived in part from bokashi, a blurring ink wash technique used by great Japanese artists like Hokusai. (Bokashi also seems to be a Japanese composting method.)

In photograph terms, bokeh is caused by a great number of factors, including:

  • the lens and its optical design
  • the way a scene is lit
  • the motion inherent to a subject
  • the aperture (f-stop) used
  • the quantity of out-of-focus elements in a scene
  • the way a scene is lit

Lens designers know that depth-of-field gets shallower for close-up subjects. The converse is also true: Going outwards from infinity there is infinite depth-of-field.

Since macro photography therefore implies shallow depth-of-field, there will be focus blurring even at f/64. Taking this in mind, some speciality macro lenses are made so that they tend to produce good bokeh. As the manual for my Nikon PC Micro-Nikkor 85mm f/2.8D puts this, “Rounded diaphragm opening makes out-of-focus elements appear more natural.” [sic]

Kiss Me

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More important than the technical considerations of what creates good bokeh is the ability of a photographer to recognize pleasing bokeh and to work to enhance it.

You should look closely at the bokeh characteristics of your photos, particularly close-ups and portraits. Experiment. Try to understand what happens to your bokeh when you change your f/stop (use the depth-of-field preview to get a sense of this while taking the photo). Work with your photographic compositions to see if you can enhance the bokeh by slightly changing your position, the lighting, or your precise point of focus.

Realize that the bokeh in a photo is as important, or even more important, than any other element. For example, in the photo I took of a white California poppy below, the flower bud and waterdrops are nice, but the purple bokeh is what makes the photo.

White California Poppy

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Posted in Photography

Do You Know the Way?

Jack was kind enough to come with me for another night hike up the beast, Mission Peak. This time, I didn’t forget my tripod. Looking up from near the trailhead, where cows grazed along side the Silicon Valley McMansions, the summit looked shrouded in clouds.

When we got to the summit ridge, we were encased in white fog. We pressed on for the workout, if not for the photos. Then the fog started to breakup.

From the top, the lights of San Jose looked startling below the roiling hills. Remaining clouds, one of them pointing right at San Jose, appeared black where the thickness of the fog layer preserved them from ambient light. I fired off this thirty second capture, and within a minute or two the clouds were gone.

Posted in Digital Night, Photography

Creature of the Night
(or, the Were-Photographer)

With all the night photography I’ve been doing lately, I’ve begun to feel a bit like a night owl. To put this in another context, sometimes I think I am a mole blinking at the sunlight. Weird for a photographer. In fact, maybe I am becoming a were-Photographer.

My friend Mark reminded me recently that there is more to photography than darkness. I don’t have to be a mole, or a creature of the night.

Although I do tend to focus on my current photographic obsession, whatever that is. So I guess I’ll be photographing the night for a while more. Until I go on to the next photographic obsession.

In the spirit of recognizing that there is more to photography than digital darkness, here’s one of my first captures from Arch Rock while it was still somewhat light. The photo shows the remote side of Point Reyes stretching down to the great cape culminating in the Point Reyes lighthouse. I exposed for six seconds at ISO 100 and f/4, and it was still light enough for plenty of detail to be rendered quite realistically.

The rest of the story, as light faded and the captures became more expressionistic: Night Shore; Renegade Remaining Photons; Twilight Turns to Night.

Photographers of the night unite! A-bleh (in Transylvanian accent with incisors getting longer)!

Posted in Landscape, Photography, Point Reyes