For some reason I've had several inquires lately about how I do Twilight and/or Night Photography. Perhaps it's all the colorful Christmas lighting and decorations, which do add a lot interest.Most of the questions have been coming from Realtors and homeowners wanting something special and different to market their homes. Last year I even had a real estate virtual tour company out of Los Angeles contact me asking how I produce my twilight shots. I was a little surprised since this was a rather large company already providing that same service (among many others) to their clients.  After I related my work flow, he responded with "that's not at all how we've been doing it, but I like your results better."  I never did find out how he was doing it, but I thought I'd share how I do it.

First of all when it comes to commercial twilight photography of homes, shopping centers, resorts, etc. I keep it as fast and as simple as possible; for two reasons. First, I generally don't get paid enough to have assistants and special lighting to move around.  Secondly, the window of opportunity for the best light of the evening is very brief.  If I'm going to get more than a couple of unique shots from different viewpoint locations, I have to work very fast. I've read the steps other photographers take and most get outstanding, perhaps superior results, but the time it takes is far too long and it can take multiple nights to get the assignment done. That's okay for a lot of them as they can often command large fees for their services. The most common question is "when is the best time;" meaning how dark out should it be.  And the answer is, like so many things--that depends!  It depends on the season, clouds, weather conditions like fog, environmental conditions like pollution,  your compass direction relative to the Sun, and more.  It's nearly impossible to predict where and when the sweetest light will occur but you'll know it when you see it.  I've been hired to do dusk shots only to have the client select the sunset shots because of the color in the sky. We should probably define a few words like what exactly is twilight and dusk.  Dusk occurs after Twilight and is the beginning of darkness in the evening but before the blue disappears. Long exposures at this time can produce beautiful deep indigo blue. Twilight is the time between Sunset and Dusk (or between dawn and sunrise) where sunlight is scattering in the upper atmosphere and illuminating the lower atmosphere and land features.  The sky can be too bright during early twilight, especially if there are few or no clouds, in which case I often use a Graduated Neutral Density Filter. In addition to the occasional use of a GND or polarizer filters, a tripod is an absolute must since this is low-light photography.  Its also a good idea to have a shutter release cable.  There is one other piece of equipment I find essential for dusk and night photography and that is a high power flashlight, preferably one with a warm or yellow hue to "paint with light."  I like to use Surefire flashlights as they are lightweight, small and put out a lot of candle power.  Since we're on the subject of equipment, I'll also mention that its quite helpful to have a camera with a large, sensitive sensor which can keep the noise down with high ISO settings.  Quality glass is also important, but that's generally true in any light condition.  I use a Nikon D700 for most of my low light photography projects and I always shoot in RAW as I'll need as much leeway as I can get for color balance and other post production. Here is the basic workflow I use for twilight, dusk and night photography:

• First I determine when Sunset is and arrive on location about 20 minutes before. I scout the location to determine the best angles to shoot from.
• If it is a home, I note which sides will receive the most and least light as the Sun goes down. This will determine which side of the building I'll concentrate on first and last.  I'll also make sure all the inside and outside lights are on including landscape and pool lights if any.
• Although I'll be making adjustments to my camera settings throughout the evening, I generally start out with lowest ISO possible and in Aperture Priority.  For architecture and homes, I want a sharp focus from foreground to background so I typically start out with an aperture around f/16 and let the camera select the shutter speed. This will give a good sense of what to set when I eventually change to full manual mode as the light becomes scarce.  Also, small apertures can produce a nice flare on small artificial light sources.
• I start composing test shots from each location. If I think there are some good sunset shots I begin to capture those using a NGD filter to darken the sky while waiting for low light.
• As an area becomes darker, and the scene becomes illuminated primarily from artificial lights, I'll pull out my Surefire flashlight and will quickly use it to paint light on darker and/or more interesting surfaces of the building or landscaping while the shutter is open. During late twilight and dusk my shutter is usually open about 10 to 15 seconds.  If necessary, I'll raise the ISO to keep the shutter in that range, but I try not to go over an ISO of 800 or 1600 to keep the noise down.  When doing low light landscape photography I'm willing to go longer if necessary [See Inset-1].
• It's during this time I move as fast as I can from each previously scouted location capturing a series of shots.  There will become a time when the light reaches a range of contrast that becomes too great.  That is the shadows become black and the artificial lights begin to blow out.  This is when I usually quit for the evening.  I say usually, because I recently discovered its possible to get very satisfactory results using HDR for night shots; but that's topic for another time.
• The location captures was half the work.  Next, I take the images to the digital darkroom for post production editing.  Generally, all I'm trying to do here is balance color, dodge and burn the shadows and highlights a bit, and correct for lens distortion. Since I don't have PC (Perspective Control) lenses, I rely on Photoshop to straighten my verticals.

A one evening commercial photography session of a home, complete with post-production editing, will take me about 4 to 5 hours and produce about six unique images for delivery to the client. Inset-Left. If the landscape includes the night sky I use a shutter speed as long as possible without creating star trails, unless of course I want star trails.  How long that is depends on the focal length being used.  Some time ago I came across a helpful formula to determine what that was.  You take the number 700 (I don't know why) and divide into it by the focal length of the lens.  Don't forget to take the crop factor into consideration.  You want to use the effective focal length.  For example, an 18mm lens mounted to a DSLR with a typical APS-C sized sensor and a crop factor of 1.5 would have an effective focal length of 27mm. 700 divided by 27 equals approximately 26 seconds.  This is the maximum amount of time the shutter can be open without clearly discernible star trails.  This is obviously a big advantage for wide angle lenses. Telephotos and telescopes will require a mechanism to compensate for the Earth's rotation.  If more light is needed, raising the ISO or increasing the aperture size will be necessary.  Although HDR in night photography can further extend the dynamic range in a scene, it is not a realistic solution when movement, including Earth rotation, is present.