Shooting a city’s skyline offers a photo rich environment. I live in Indianapolis, so I regularly use the downtown as a subject of, or backdrop for my photoshoots. Not a huge downtown, but still a solid photo subject. Since I do lots of nighttime photography I often capture downtown Indianapolis after dark. Many will agree cities take on a different look and richness of color at night. Most major cities are over photographed, so during the day I’ll try to do something different. I will shoot with a fisheye lens, a composite panorama, or with brooding clouds. Anything to get a different look.
When I shoot a skyline or cityscape at night and day I always us a small aperture as I want a deep depth of field. Normally, F/9 or smaller. This also gives you much wider selection of lens to choose from. Also, use a wide angle lens. I almost always shoot cities at 28mm or wider.
At night an aperture of F/9 or smaller creates starbursts on strong light sources which I enjoy. Bring your tripod because it’s needed at night, and I use an electronic trigger to limit camera shake. I set the camera to aperture priority and set the ISO as low as possible to minimize noise. I allow my camera to set the shutter speed while in aperture priority. Exposure often end up in the 30+ second range. If I’m not getting the look wanted I’ll adjust the exposure compensation. That’s about it.
At day, there is nothing special to it. On a bright day I keep my aperture as small as possible and almost always handhold unless I’m shooting series for a panorama which I stitch in Photoshop CS5. As noted above keep your aperture as small as possible to get the depth of field you want, and set your camera to aperture priority. Now go out and shoot your city.