Discussion - Star Trail
I really need to get back on task with my "Photography Basics" posts. Hopefully soon. Even though I haven't talked about that stuff yet, I hope that you can get something out of my discussion concerning a handful of my more recent photos. Granted, it might be nice to describe the photos that didn't work out, but since I didn't get those photos scanned it would be hard to do that!
a14 - 15 Minute Star Trail, Joshua Tree National Park
Comment: Point your camera at a clear night sky, open up the aperture, keep the shutter open for a while and see what happens! I have tried taking these photos throughout the years with varying levels of success. You have to be someplace with minimal or no light pollution and have a location that will not have extraneous light falling on your lens. If you can get the photo to work, I love all the different colors that are actually present in the stars!
Technical aspects: These photos are actually not that hard to shoot, but you do need to have a few things - however if you are serious about your photography these are standard anyway. The first thing is a camera that allows you to keep the shutter open for as long as you want. My camera is an old manual camera and after 1 second on the shutter ring there is a "B" for "Bulb". This keeps the shutter open for as long as the release button is pressed. However, I do not want to be standing with my hand on the camera for 15 minutes so I have a locking cable release. This little device screws into the shutter button and I can lock it open for as long as I want.
The next choice that needs to be made is what lens to use. Zoom lenses are fine as long as they are tight enough to not change their focal length while pointing straight up for a long period of time. Another thing to consider is the "integrity" of the shot. Light pollution is a problem in a lot of places and usually the closer one gets to the horizon that light is present. Depending where you are in the country, airplanes might also be flying around which would ruin a photo with a nice straight line or blinking dots across your frame. If light pollution on the horizon and airplanes are a problem, then wider-angle lenses might not be the best choice so that you can isolate a particular patch of sky. Since stars are not really all that bright you will also want a decently fast lens to capture as much of that light as possible. Using a lens that is f/4 or above might not get the fainter stars. Personally I like my 50mm f/1.8 normal lens for this work.
Another must is a good tripod, and one that will allow you to point your camera where you want it and keep it steady throughout the shot. Strictly speaking it doesn't matter how tall the tripod is, but if you want to look through the viewfinder to compose the shot then having one that is taller than you is nice. Another good reason to have a taller tripod is to keep out unwanted, extraneous light. All it takes is one person to shine a flashlight across your lens or a car to go by to ruin the shot. Elevating the camera (and using a lens hood) will keep that problem to a minimum.
Finally, you need film (assuming you are like me and still using the stuff). Since we are dealing with faint subjects, the faster the film the more stars will be recorded on film. This photo was shot on Fuji Velvia 100 film, which isn't fast, but it still did a great job getting the stars and since it is Velvia, the colors are rich and saturated. I have tried Velvia 50 film and it didn't work. Provia 400 film is great because it is fast, but not as rich of colors as the Velvia.
Composition: Actually in a way this photo didn't turn out the way I would have liked it. There is one element missing that I would have liked to have, and that is something else in the photo to anchor it, something that doesn't move relative to the camera. I actually tried putting other stuff in the photo, but where I was at I didn't like the options and just gave up and shot this. One suggestion for composing a shot with a foreground object is to use a flashlight to illuminate the object so that you can actually see it through the viewfinder. One problem that I run into since I usually do these photos in or near a campground is my foreground objects being lit up, even for a second, by a car or flashlight. This is fine if that is what you want, but I want to have a dark, silhouetted object to anchor my photo.
The only other thing to think about when composing these shots is that the farther you get from the North Star the less of an arc your star trails will be, and vice versa. Just something to think about!
One final thing if you are using film for these shots. Before actually taking photos of the stars, take a few photos of something brighter. This will help whoever mounts your slides figure out where the frames are and not cut anything off because they can't see what is going on! It might also be nice to let them know what these photos are so that they don't assume they are blank frames at first glance.
Please comment if you have anything else concerning this photo!
Labels: photo discussion, star trail
posted by Mark Vander Pol at
1/30/2008 05:58:00 AM
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