Chapter 8

Update January 2011

Ted Kinsman

www.sciencephotography.com


Time-lapse photography of construction sites


Time-lapse photography of construction is a popular way to document how a building was made as well as a unique visual element in a documentary. It is quite common for art directors and directors to ask about a time-lapse sequence for their documentary on the role of a new art center, bridge construction, renovation of main street, or just about any public project.


It is common for these requests to be stated without much prior concern for budget constraint, or even the actual practicality of getting a camera to the angle desired and keeping it there for many months.


Many time-lapse cinematographers are asked to make a quote on filming some huge project that has never quite been filmed before, and asked to complete the project on a shoe string budget. The goal of this chapter is to show not only solutions to standard situations, but also show some of the unexpected problems that can pop up.


The budget that is presented mandates the format chosen for the project. This has a few exceptions. If the client wants monthly updates for a web application, then the project will have at least one digital camera on board. If the budget has no limit, than a photographer can be hired for a year be on site and supply weekly updates. Most projects are on a medium budget that can not afford 35 mm film.


The following pages will present various options and techniques for filming on a construction site for long periods of time.


There are currently a growing number of ways to time-lapse a construction site. I will address each of these in tern. Each of these systems has advantages and drawbacks.


1. A web camera (webcam) is set up to collect images to upload to a web site, and the web master also programs a file be permanently archived on a hard drive.


2. Use a digital camera tethered to a computer to collect digital files.


3. A 16-mm film camera is used to collect individual frames from the site.




The least expensive of the techniques is to get a webcam and setup a scrip that saves an image every few minutes to a server. There are now several firms that will ship a client an HDTV res webcam and back up all the files everyday over a cell phone link.


The only limit appears to be that several of these standard time-lapse programs only allow 9,999 images to be collected, and that some of the programs have the ability to crash at 12:00 am on Monday morning. These odd features of a program are not always obvious to a person testing a program. As with any time-lapse set up it should be fully tested for over one week before it is placed on a long duration time-lapse shoot. I can not stress this point enough!!!!




One of the big drawbacks to all time-lapse camera systems is the instability if there is a power outage. Since most of the programs can not be configured to run upon computer start up, if the municipal power is cut for longer than an uninterrupted power supply can supply power, than both the computer and camera will go off line. This event is called a catastrophic failure and needs human hands on site to fix. This can be quite a problem if there is not a person on site who is looking after the camera and if the time-lapse photographer is many miles away. Though out the United States there is a probability of 100% that any specific site will loose power for longer than 15 minutes in any given year. In some locations this can be a weekly event.


There are no 100% reliable computers, and the systems must be checked on a basis that is the same as the amount of footage that is acceptable to loose. That is if the project can afford to loose a weeks worth of images, then the system can be checked once a week. If there is a phone line near by the computer can be tied into a hard wired phone line, or a cell phone modem to that sample images can be downloaded at the end of each day to determine if everything is running correctly. The computer can also be attached to an Internet link and the digital files can be down loaded each night.


There are several computer problems that a time-lapse photographer be aware of:

Some laptop computers turn off if they get too cold.

The computer must be in a state where it does not enter a sleep mode - many programs will not wake up the processor.

Then computers get too hot or too cold the CDROM writer will not work.

Computers left in a shed on a hot roof will need to have scandisk or a hard drive mapping utility run about every three weeks

Some sort of back up data collection system is a must.

Back up camera and computer systems are also a very good idea on long duration shoots.

The most popular technique currently used is a digital camera tethered to a computer. This has the same problems mentioned in the past few pages concerning a computer system. The advantage is that the images are quite sharp and can be quickly converted into a digital time-lapse movie. The whole system is not limited to any on board camera memory, but is limited by the size of the computers hard drive. There are several cameras on the market that can be run in this mode including several canon models. The resulting images are much better and are high enough resolution that there is room in the image for panning and zooming. The art director for the project also has several thousand high-resolution stills for various other projects besides a time-lapse movie.


It would be extremely rare to shoot film these days, and it is also not a very cost effective option. I will forgo talking about film here.


The use of a web camera is also a good solution for a system. The web camera will have to be maintained on a daily basis by some sort of computer guy. A web camera in combination with a second system is a nice way to see what is happening at a remote site. The problems with such a system are numerous. With an active web site, there are often computer problems and the system will probably not be able to be self starting from any serious power failure. This will insure that there needs to be a person on site to fix any problems that may appear. There are a number of such system running every way and the images are available to any person who chooses to view these web cameras on the Internet. 


Any specific web camera or program that is in current use at the time of this righting will be totally out dated by the time this text reaches the reader. The active time-lapse photographer working on a construction project will need the resources of a professional programmer to set up and debug a web camera system. IT should be noted that some of the higher end digital cameras have the ability to be run as a very high-resolution web camera. One such camera is the Cannon D30 which has the ability to run in a tethered more. This camera and software would also require special code to be written to use it in a web camera application.


One of the last options is also the most recommended these days. A digital camera is out fitted with a 16 gig flash memory card (or larger if available) this card is large enough to hold over 4000 images at 1200 x 960 . The digital camera is outfitted with a remote battery and a digital controller. The digital controller is used to tell the camera to take a picture and can be programmed for any specific wait time. These controllers also have the ability to shut off when it is dark out such that precious flash memory space is conserved. Such a system taking a picture every 5 minutes will run for alt least 20 days with out needing the flash memory card backed up to a laptop, or replaced. One solution for a remote site is to have a local photographer visit the site and change the flash memory every 2 weeks and swap flask memory cards. If the wait time is increased, the camera can run for longer duration’s with out having to have the flash memory down loaded to another computer.


This specific system is also quite power efficient and suitable for use in remote locations were power is at a premium and all electricity must come from batteries. In the event of a catastrophic power failure where the municipal power is lost for more than 15 minutes this system would pop back on line and not miss a single shot.


This system can also be run fully off of a 12 v battery. The battery can be attached to an auto charging solar collector and run for many months at a time with out taking any municipal power. This system is once again ideal for remote locations.


There are an increasing number of companies producing these camera controllers specifically for time-lapse construction applications. Such a unit is pictured below. Have a look at Mumford time-machines online.

 



No mater what system is chosen of a construction time-lapse project there are several basic issues involved with all the projects.


The camera and any related computer equipment need to be housed in a weather proof housing. The housing can be a common video security camera housing as is often seen in parking lots, or a specific camera shed can be built. To have a camera shed built is the best option since this allows lots of space for numerous different devices that are often required.



This camera shed has a slanted window, the camera is mounted on a huge tripod that supports both a video system and a film camera. The large window allows the camera to be aimed at different areas once the shed is built. This camera shed was used on a one year project to film the construction of a unique design of water tower. This was quite a dice design with enough room to carry a laptop into the shed and use a local network to pull the data off the computer collecting the images. This shed was equipped with a nice rotating vent on the top which helped equalize the temperature during both the summer and the winter. The equalization temperature was important to keep ice and dew from forming on the window. The air vent had a screen installed that kept most bugs out. What bugs that did get in were caught on fly paper placed on the inside of the shed.

This system worked well to illuminate almost all insects though out the season – that is until the plague of the ladybugs.


This site was located about 10 miles south of the shore of Lake Ontario, one of the Great Lakes. Due to some strange weather conditions, the winds blew in huge numbers of these insects. The lady bugs saw the dark are of the camera shed and descended in unprecedented numbers. A five gallon shop vacuum cleaner was filled with lady bugs that had wiggled in to the shed from a crack in the door. While this might seem like a huge amount it was only a small fraction compared to the huge amounts flying around out side. There was no possible way to remove the ladybugs, and three weeks of photography was lost due to their presents in the area. Several critical frames were recovered by digitally removing the bugs, but this process was not feasible for the total duration.


There are other surprising issues that will often appear on construction site. This camera shed was installed and then the project supervisor decided that it should be raised four feet into the air. Although this was quickly accomplished it did give the resulting film a quick change of view in the first few seconds of the film. This camera shed had 4inch by 4 inch posts set into a cement foundation. The camera produced a rock steady image in even in high winds. That is until the construction crew poured 350 tons of reinforced slabs a few feet to the side of the camera shed. The whole area surrounding the cement slabs was depressed a few inches – camera shed and all. As much as it was depressed and the resulting frame was slowly moved for a few weeks the shed rebounded to almost the original alignment when the cement slabs were removed. It is quite important that the camera be located in a site that is immune from such problems.


On any construction site the primary object is to record the action and thus the capture the sequences various procedures take place. The placement of the camera would be ideal if it could be placed to the south of the construction (here in the Northern Hemisphere) such that the building obtains full illumination from the sun. Unfortunately a location of the south side of the building is not always practical. The construction site manager will often have critical processes taking place where the optimum site would be to place a camera. In such situations the time-lapse photographer must bit their tong and set up the camera in the best possible location out of the way. It is better to get an average shot that get a few weeks of great footage only to have the camera in equipment moved to some distant location whit it is deemed the camera is now it the way.


The timing associated with construction time-lapse often changes though out the project. A building might have a time frame of one year from the time the ground is broken until the time that offices move in. The building does not progress in a uniform fashion. The ground breaking happens quite fast. Holes are dug and cement is quickly poured in a matter of two weeks or less depending on the size of the building. During this phase of the process a wait time for exposures would be in the five minute range. The construction phase of the project happens also quite fast. The steal usually is constructed off site and brought in on trucks and bolted into place in a matter of days. The steel assembly is often the most exciting aspect of construction and it is this phase that the finished time-lapse movie will want to include the most material of. During steel assembly a wait time of 1 min to 4 minutes is highly desirable. The shorter the wait the better during this phase – remember that undesirable frames can always be removed from an edit, while it is impossible to obtain missing images. It is always better to over film, or collect more images than are thought needed. The nest stage of the construction process is for a building to have a skin placed on it. In architectural turns, the skin is called the facade and it typically is some sort of pre-assembled materials that are bolted or glued onto the outside of the building. The facade is also another process that takes place quite quick. Good brick layers can cove the front of a good sized building in just a few days. This stage of the process is best filmed with a wait time of about 1-minute. The facade of a building is highly weather dependent and it is often the case for the construction supervisor to schedule a certain facade to be put on at a specific time, only to have the procedure delayed for days of weeks due to the weather. It is also common for brick masons to cover the exterior wall of a building with a huge plastic tent to keep themselves and the mortar warm while they work in cold temperature. This is the bane of a time-lapse photographer since all that is recorded is a tent going up and when it is removed there is a beautiful facade in place.


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