10 Tips for better construction photography

05 - Cameras should have three legs

If you already bought a digital camera to document your construction progress you may be looking for the next piece of equipment that you can buy to improve the quality of your pictures.  I would like to put in a plug for an underutilized piece of equipment that you probably already own, namely a tripod.

Digital cameras come in many weights and sizes, but they all suffer from the same problem.  They need a fair amount of light to record an image properly.  The equivalent film speed on most digital cameras is around 50 ASA.  This means that you can properly expose an image in bright sunlight at an aperture of f16 and a shutter speed of 1/50 sec.  

Using a normal or wide-angle lens a shutter speed of 1/50 sec is fast enough for most people to shoot hand-held without inducing motion blur.  If you have a zoom lens the acceptable shutter speed goes up roughly by the zoom factor.  A Canon G3 for example has a zoom ratio of 4.  This means that when the lens is zoomed out to it’s maximum telephoto setting you will need to use a shutter speed of 4x faster (i.e. 1/200 sec) in order to shoot hand-held without motion blur.  Some people have a steady enough hand that they can get acceptable images at lower shutter speeds but a good rule of thumb is don’t shoot hand-held at shutter speeds below 1/50 sec for normal and wide angle lenses.

If the interior of homes under construction were illuminated like outdoor scenes  in bright sunlight there would be no need for further discussion.  Unfortunately that is hardly ever the case. Lighting levels within homes under construction can be anywhere from 7 to 12 f-stops below the outdoor lighting level. It may be a bright and sunny day outside but inside an interior bathroom it may be darker than a witches lair illuminated by a single candle.  In order to get an acceptable image in a room that dark you need to do one of two things.  You need to bring in additional light, or you need to use a shutter speed longer than 1/50 sec, which means you need to use a tripod.

You  may think you could increase the film speed to deal with low light situations but the concept of film speed in digital cameras is a ruse, a case of digital trickery akin to digital zoom.  Increasing the film speed on a digital camera actually reduces the amount of light that falls on the sensor.  Digital cameras make up for the lack of light by post-processing the image to bring out detail that would otherwise be lost in the shadows.  In a brightly lit scene the results may be acceptable but in a dark room you will loose detail.

Using your camera’s flash is no panacea for dealing with low-light situations.  The light from a flash falls off as the square of the flash-to-subject distance.  While objects four feet away from your flash may be properly exposed, objects that are 16 feet away will appear to have fallen into a black hole because they will receive 16 times (four f-stops) less light from the flash.

In summary the lowly tripod is an underutilized tool in construction photography.  It is the most reliable way to insure that your images are sharp and properly exposed even if you are photographing a witches lair by candlelight.

 

Ken VanBree is the owner of Imaging Perspective, a Bay Area firm that specializes in as-built construction photography.  Questions or comments are welcome: ken@imagingperspective.com