When shooting architecture, the best possible luck is to have existing lighting or ambient light that cannot be improved upon. It happens, but not often. For evening shots it almost never happens. It is much more common to find interesting, nicely designed interior lighting than good exterior lighting. Most buildings, especially large commercial buildings are either poorly lit or lighting was installed merely to prevent darkness and address safety concerns without much consideration for design and aesthetics.
Sometimes exterior light fixtures have to be blacked out with black wrap or duvetyne because they can ruin the shot – often they are installed too close to the building, they are too intense, or saturated with a bizarre mercury vapor orange. You cannot turn them off. Exterior building lights are usually on a programmed schedule that cannot be accessed or altered by the usual maintenance and security staff.
For evening shots, it is hard to know what the solution is until you see the building about twenty – thirty minutes after sunset, which is not always possible. I always check the web in advance to keep track of the exact time of sunset. I try to know my compass directions precisely, checking directions on Google maps and my I-Phone compass until I understand what is likely to happen as the sun changes position. There is software that goes deeper into this issue, but I don't use it.
When shooting the built environment outdoors, it helps to use studio lighting techniques analogously. Will the light be diffuse like from a soft box (light cloud layer), or hard and bright like a strobe head (direct sun)? Where are the bounce surfaces? Sometimes your best light source will be light bouncing off a white wall or a white building. How will these light sources change as the sun moves across the sky? The time of year is important, and the way the arc in the Southern sky affects the setting sun.
I was hired to shoot a retail space in a landmark building in Los Angeles. It was on a narrow, busy downtown traffic corridor. I thought I would have to bring my own lighting for the evening shot because the street was hemmed in by tall buildings and more than half of my facade was nearly pitch black at night.
I had been there for scouting once during the day, and once at night after sunset so a visit at the key time in the twilight hour was missing. I came with lots of lighting – a 3200 watt second pack, three heads, gels and soft boxes, three Ari heads, cables and grip accessories, and a capable experienced assistant. Preparation is everything, but with all my preparation I was not prepared for finding that the light in this image was already there and could not be improved upon.
In the end, no amount of finesse with extra lighting could equal the ambient light that was already there in the twilight hour. Why? The street the facade was on runs north and south in downtown Los Angeles and this was a winter shoot. The light from the setting sun in the south (to the left of the shot) created a massive projection, channeling directional diffuse light from the left (the south) to the right (north) and raked across the geometric details in the art deco facade to create perfect modeling for a few minutes each evening. Because the buildings across the street from my shoot were seven stories high, they flagged any diffuse light that might have come from behind the camera and protected the side-lighting from loss of contrast. None of my professionally lit shots of the building came close to the beauty and uniform distribution of the light that was already there.