The photograph was taken along Green Street in Urbana, IL, just north of the student union at the University of Illinois at Urbana-Champaign (UIUC). The view is westward facing, looking down Green Street at the eastern-most end of Campustown. There is more on Campustown and UIUC below. In the center of the photograph is the intersection of Green Street and Wright Street.
One of the most common questions that I get about this photo is, "where you standing in the middle of traffic while taking this photo?" Let me put your worries to ease. No, I was not standing in the middle of traffic. The photograph is just setup to look that way. While I was near the road, I was not in the road itself. I have a similar photo taken in downtown San Jose, California, where I was safe and sound on the sidewalk when the photo was taken.
That question is then commonly followed up with, "are you sure you were not standing in the middle of the street?" Yes, I am sure. I was there, and saw the whole thing go down.
For those unfamiliar with long exposure photography, the shutter is held open for a prolonged period of time. Because of that, movement within the field-of-view is captured in the final photograph. This can cause a variety of effects, which can be subtle or more pronounced, depending on what the photographer desires. Several additional examples of long exposure photography can be found here.
For this photograph, I setup the camera at night near an intersection with some traffic, but not too much. This ensures there are cars with headlights and taillights on passing by the camera. Because the headlights and taillights can be quite bright, especially when those lights are pointed towards the camera, having too much traffic would be bad. Because headlights tend to be brighter than taillights, balancing the headlights versus the taillights can be a factor as well.
The overall effect is that the headlights and taillights trace streaks of light along the cars' paths as they pass by. Because the cars are not as bright and not still for long, they do not really show up in the photograph. Instead, bright sources of light and stationary objects are emphasized. Only hints of the cars remain. And even then, the hints typically the light reflecting off the cars' exteriors, creating some of the more erratic lines. This is more easily seen on the right side of the photo mixed in with the streaks created by the red taillights.
The exposure lasted for 25 seconds, but the cars passing by any given point in the photograph where there for just a moment. This was accomplished by timing the exposure with the traffic light. As a result, the stationary features of the photograph, such as the road, sidewalks, trees, and buildings, are captured over time. Similar to the cars, these elements of the scene are not particularly bright either. However, the fact that they do not move gives their light a chance to build up at the same location on the sensor over time.
Because the headlights and taillights are so bright, relatively speaking, it does not take much time at all for their light to build up on the sensor. Instead, these bright elements create streaks of light that trace along the road's path, hovering just above the road's surface. This effect adds a lot of movement and life into the photo.
If you look closely at the photo, you will also see some people along the sidewalks near the intersection. In some cases, these people look a bit ghost-like. This is because they stood still long enough for the camera's sensor to build up some of the light bouncing off of them. However, after they moved away from their location, the background behind them began contributing light instead. The overall effect in the final photograph is that they look transparent. How transparent is determined by how long they stood still during the exposure.
For those unfamiliar with UIUC, Campustown is a small area (approximately two by three city blocks) near the UIUC campus filled with bars, restaurants, apartments, and other businesses. The main drag is along Green Street, right next to the edge of campus. For students, Campustown is easy to get to and thus is a popular place to hang out, eat, party, and otherwise have a good time. It was quite common for us to venture over to Campustown to grab lunch or dinner while working on the campus.
This picture was taken in 2010, so I am sure Campustown has changed quite a bit since then. One of the main bookstores serving students when I attended, Follett's Bookstore, has since closed. In the photograph, this is the building to the right with the large glass entrance on the opposite side of Wright Street. Another well known establishment at the time was a pizzeria called Papa Del's, which has since moved to a location further away from campus.
Many students, myself included, regularly ventured out into the downtown areas of the two neighboring cities, Urbana and Champaign. These are not large cities, but there is quite a bit going on if you take a bit of time to look around. Each city has a fun downtown area with a variety of businesses, including several good bars and restaurants.
The University of Illinois has multiple campuses, with UIUC being the largest campus. UIUC had over 51,000 students enrolled in 2019 (source). With that many students, obviously there is a lot going on. After all, students tend to have quite a bit of energy. Between the university and the two cities, there is plenty to do. The number of student groups and organizations is overwhelming.
For those that desire the draw of a larger city, Chicago is 2-3 hour drive to the north. This makes it relatively easy to visit one of the largest cities in the country on the weekends. St. Louis and Indianapolis are fairly close as well (approximately three or so hours away). Both are certainly easy to get to on the weekends.
Long exposure photography, as the name implies, simply refers to photographs taken with relatively long exposure times. Typically, the photographer wishes to capture the movement of one or more elements within a scene over the course of the exposure. The resulting photograph then reflects this movement in some way. This technique can be used to create various effects, and thus is a useful technique for photographers to know.
Taking long exposure photographs can be a bit tricky. First and foremost, the photographer needs to imagine what is going to happen in the scene over time and how that will affect the final result. There are several technical aspects to take into account as well.
As with all forms of photography, managing the light in a photograph is important. Long exposure times can add yet another layer of complexity to lighting. Not only does the light build up over a longer period of time, but it may also move around and/or change in intensity. The exposure settings on the camera also govern how the movement will be captured, including how much overall movement is captured and how much each element of the scene contributes to the final image. Many factors, such as how bright an object is, how reflective it is (e.g. glossy vs matte), how fast it is moving, the use of flashes, and so on, all play a role in how an object will show up in a long exposure photograph.
Secondary effects, such as camera shake and sensor noise, have a higher chance of affecting long exposure photographs as well. Digital camera sensors tend to generate more noise when they are exposed for longer periods of time. Camera shake can become a factor as well. Even small, subtle movements can affect the sharpness of the image. For example, cameras are commonly placed near roadways when photographing the light trails created by cars driving at night. Vibrations caused by those cars can subtly and constantly shake the camera, introducing a slight blur in the final photograph.
More examples of long exposure photographs that I have taken can be found here.