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Bristlecone Star Trails, White Mtns., California

Posted by
Gary Hart (California, United States) on 22 August 2009 in Landscape & Rural.

<If a rock star can repackage previously released material in a "Greatest Hits" album, I can repost an image from a previous blog because it best conveys today's message. For the story of my capture of this image (and an easier read), check out my March 18 blog.>


"Is that the way it really looked?" (fifth in a continuing series)

I'm asked that question quite frequently, and my response is always an emphatic, "No!" The camera and the eye see the world differently; it's silly for any photographer to claim an image is "exactly the way it looked when I was there." A camera's dynamic range, visual depth, and range of focus (to name a few) are all inferior to the human eye. A good photographer doesn't submit to these limitations, he or she turns them into an advantage. Conversely, there are wonderful things the camera can do that the eye can't. All these differences combine to give the experienced landscape photographer an opportunity to create evocative, artistic images in the camera, with very little post-processing required. Today's post continues an ongoing series expressing my thoughts on using your camera's vision to your photographic advantage (and without having to resort to Photoshop enhancement).
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Expand time

Is this exactly what I saw that night in the White Mountains? (What do you think?) The first four posts in this series deal with the camera's limitations and how to turn them to your advantage. But here's something the camera can do that the human eye can't: Expand time.

While your eyes send your brain a series of consecutive images to connect into a continuous moving picture, the camera can capture all that motion in a single fixed frame, creating effects the eye/brain can't. Holding your camera stationary (on a tripod!) and leaving the shutter open, you can juxtapose sharp fixed objects and blurred moving objects. The most common examples of this are blurred water and star trails.

Blurring water is so popular that some consider it cliché. But sometimes it's impossible to freeze the motion of streams, rivers, and waves in shadow, making blurring the most aesthetically appealing approach. There is no magic formula for blurring water, as the effect varies with shutter speed, subject distance, and focal length. But doing it is fairly straightforward in that, aside from the water's motion, the scene will appear quite similar to the resulting image. Once you get the exposure right, you can play with the other settings (ISO and aperture) to vary the shutter speed. The more you try it (don't be afraid to fail), the more you'll start to identify opportunities when you're in the field, and know how to handle them.

Star trails are a bit trickier, as the long shutter speeds will record a world significantly different than your eye registers. Success requires some understanding of these differences, and of the reciprocity of exposure. It also requires a solid tripod, locking remote release, and a camera that supports bulb mode. (And a warm jacket.)

(And reading about star trail photography exhausts copious brain cells, so if you proceed from here, sit down and hold on tight.)

I've found the star trail compositions that usually work best are silhouettes, like this bristlecone. For a silhouette to succeed, the silhouetted subject needs to stand out against something brighter, like the sky or water (even though the sky looks dark, it is lighter than the foreground, a difference that will be revealed by a long exposure).

The correct exposure varies significantly with factors like the phase of the moon, the time of night (the sky is darkest right around the midpoint between sunset and sunrise), the amount of light polution, the direction you're shooting (even if you can't see it, the western horizon is brighter when sunset is closer than sunrise; the the eastern horizon is brighter when sunrise is closer), and the effect you’re going for. Unfortunately, conventional metering pretty much goes out the window with star trail photography—there simply isn't enough light. Fortunately, digital shooters have a solution….

(Now the fun begins.)

Digital shooters, a test shot will help you determine the exposure settings you'll need. Start by bumping your ISO as high as it will go and opening your aperture to its widest opening (you can even use your fastest lens for this test). Point your camera in the direction of your planned composition and meter--keep adjusting the shutter speed longer until the meter registers, and shoot a test shot (on a tripod, please!). If you don't get any response from your meter, try a one minute exposure

Review your LCD and adjust the exposure (using shutter speed) lighter or darker, continuing to take test exposures until you get one you like (this shouldn't take too many shots)--don't worry about image quality or critical focus for these tests. Once you get the test exposure you want, you can choose the desired shutter speed by reducing the ISO and aperture, counting the stops as you go--remember, halving (or doubling) the ISO subtracts (or adds) one stop of light; the 1-stop f-stop steps are 1.4, 2.0, 2.8, 4.0, 5.6, 8.0, 11.0, 16, 22, ... (it's handy to note that the 1-stop f-stop sequence is just two sequential sets of doubling numbers: 1.4, 2.8, 5.6, 11, 22, ... and 2.0, 4.0, 8.0, 16...).

So if you found 1 minute gave the desired exposure at ISO 3200 and f2.8, and you want 32-minute star trails, you can compute that 32 minutes is 5 stops more light than 1 minute (do the math—getting from 1 to 32 requires doubling 5 times). Armed with this knowledge, you know that reducing the light by any aperture/ISO combination of 5 stops will allow a 32 minute exposure that matches your test exposure. That’s the beauty of photographic reciprocity. In this example, to reduce my light by 5 stops I could drop down to ISO 400 (3 stops less light than 3200) and f8 (2 stops less light than f2.8), or ISO 200 (4 stops less light) and f5.6 (1 stop less light). Both total 5 stops less light, allowing me to reciprocate, adding 5 stops of light by going from 1 minute to 32 minutes.

(Are you still there?)

Now you’re ready to compose (and I’m exhausted). I find it easier to compose and focus off the tripod. Focus is a total pain, usually involving flashlights and lots of guessing. In my exposure settings I usually opt for a higher ISO to allow a smaller aperture, just to allow more depth of field (increasing my margin for error). A shorter focal length (wide angle) also increases your margin for focus error. And if your subject is at infinity, you can sometimes find a distant light (such as headlights or the moon) to autofocus on. Just be sure when you’re ready to shoot that you put your camera in manual focus mode—otherwise it will forever hunt for focus.

And now it’s time to shoot. I’m not going to talk much about in-camera noise reduction (black-frame subtraction) except to say that some photographers use it and some don’t—turning it on (it’s usually buried deep in your menu system) doubles your exposure time by taking a second picture of equal duration with the shutter closed, then subtracting noise it finds in the black frame from the actual frame. In my example, using black-frame subtraction, I’d have to wait another 32 (or so) minutes after my initial exposure while my camera did its processing.

Put your camera on the tripod (stabilizing it with your camera bag or some other weight isn’t a bad idea), adjust the tripod head to position your camera (but don’t change your focal length or you’ll mess up your focus—trust me on this), put your camera in bulb mode (if it isn’t already), click your shutter (if mirror lock-up is set, don’t forget to click a second time to release the shutter), engage your remote lock to hold the shutter open, and check your watch. Now there’s nothing to do but sit back and take in the sky.

Questions? Hey, where'd everybody go?

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Thanks for visiting. Even if I don't respond, your comments are always read and appreciated.

Barbara Kile from Ft. Worth, United States

Awesome shot. And, yeah, you almost lost me, but it IS late.
:-)

22 Aug 2009 5:09am

@Barbara Kile: Thanks, Barbara. And thanks for sticking in there until the end. :)

pernilla from Andonno, Italy

I'm still here :) Beautiful shot! The star trails works really well together with the silhouette. Interesting post to. As a former press photographer my interest for nature is newly discovered and as soon as I have become more friend with my tripod I will try this out. Thanks for an inspiring post.

22 Aug 2009 6:23am

Ana Lúcia from Leiria, Portugal

Gorgeous.

22 Aug 2009 9:22am

Anina from Auckland, New Zealand

AWESOME!!!!
I love this!

22 Aug 2009 9:32am

Don Smith from California, United States

I was with Gary on the night this image was made, and I can tell you that all the technical jargon aside, the sensory experience of sitting on a 10,000 foot mountain in the middle of the White Mountains, with the lone howl of a far away coyote, and 4,000 year-old bristlecone pines and a star-filled night sky as out palette, far outweighed the beautiful resulting images. We all love making incredible nature images (as Gary has done here), but it is our connection with nature that is truly the a huge part of the enjoyment for me.

22 Aug 2009 4:34pm

@Don Smith: Yes, Don was one of three other photographers with me that night. The others light painted, but being something of a natural light fanatic, I opted for a silhouette. As I mentioned earlier, you can read about my experience capturing this image in my March 18 blog.

john4jack from Corvallis, Oregon, United States

Very, very cool photograph. Don Smith's last sentence certainly speaks for me. On "did it really look that way?", I am reminded of how Ansel Adams always laughed and said that he had never seen a sky look the way that skies looked in his prints. As I frequently do with you and Don, I have printed out your commentary (tutorial) for future reference. Thank you.

22 Aug 2009 5:28pm

@john4jack: Thanks, Jack. Over the years it's become increasingly apparent that aspiring photographers are inhibited by the mistaken belief that they need to capture a scene exactly as it looked when it was there--that's simply impossible. All of us color shooters who have been doing this for awhile shot for years with film, so (without Photoshop or a color darkroom) we learned how to use our camera to be creative. Digital makes some things easier, but most of what I talk about can also be accomplished with film.

Viewfinder from Bradenton, FL, United States

No words necessary. Just beautiful.

22 Aug 2009 5:41pm

john4jack from Corvallis, Oregon, United States

Following up on your response, I find an analogous situation in expecting your print to look exactly like the monitor screen. I have done detailed soft proofing with a well-calibrated monitor, but there still are variations. Just the fact of the difference in types of light creates variations. However, this has never been a big deal for me. Often I like the print as it comes out better than what I see on the monitor. If I don't like what I see in the print, I figure out what modifications I need to make and go back and make them. My primary concern is always with the print.

22 Aug 2009 6:36pm

@john4jack: Yeah, I think people obsess too much about that kind of stuff, particularly in nature photography, where color is so subjective in the first place. That's one reason (among millions) I don't do weddings--get skin tones wrong or the color of Aunt Connie's dress, and you'll get no end of grief. I try my absolute best to get my colors as accurate as possible, but just can't afford to obsess about it. Continuing your analogy, I was extremely concerned about the color of the images in my book, which required a conversion to CMYK. I was thrilled with how well they came out, with only a couple that I felt were clearly (but still tolerably) off. It helped that the publisher insisted on proof prints for each image, a real pain, but in hindsight worth it.

Bill Jennings from (Bay Area Northern Calif), United States

Love the star trails, and how you defend the art of photography: by teaching us to learn what the camera sees, and to use that creatively to open up new awareness of familiar subjects. Well done.

23 Aug 2009 7:26am

daniela scharnowski from Berlin, Germany

This is a beautiful long exposure effect - with an excellent bizarre motive - lovely athmosphere - a little scary but the beauty wins =)

23 Aug 2009 10:56am

Mirjam from Kiev, Ukraine

Thanks for sharing your experience and the shot

23 Aug 2009 11:00am

Scott Schilling from San Martin, United States

The background sky color and tones are perfect in this Gary! Great work with the tree silhouette also! thanks for the tip on the iceplant. I will clean that up in the original. Have a great week along the coast!

23 Aug 2009 6:23pm

Curly from South Shields, United Kingdom

Terrific result and worth all of the effort.

23 Aug 2009 8:03pm

Ashley from San Francisco, United States

Awesome tutorial! In-person explanations are great, but I love having a print version - I like to read over the confusing bits multiple times until they make sense. Thanks for writing this!

24 Aug 2009 9:47pm