St. Paul's cathedral in London at night from across the Thames​
Aperture
From ApogeePhoto: For highest image quality, use medium to small apertures (large f-stop numbers like f/8 to f/11 or higher) to achieve sufficient depth of field. Note: Large f-stop settings tend to create beautiful star effects on street or building lights while large apertures (small f-stop numbers like F/5.6) minimizes that effect.
From LightStalking: Depending on your lens/camera combination, aim to shoot at an aperture of around f8-f11. Any smaller than this and you will start to introduce diffraction, which will reduce your image quality, any wider and you run the risk of getting your foreground out of focus.
Use Your Histogram
From Digital-photo-secrets: Your histogram will tell you whether you’re capturing the right colors with the settings you’re currently using. If most of the graph is slanted toward the left, you need to increase your exposure time. If most of it is toward the right, you need to decrease your exposure time.
Focus
From ApogeePhoto: Focus on the skyline, as this is your main subject, and it should be crisp and clean. When an interesting foreground subject is included, focus on the objects in front of you and choose your aperture wisely. Utilize the depth of field preview to ensure high image quality and sharpness from foreground to skyline. A split neutral density filter might come in handy to handle the contrast between bright sky, skyline and darker foreground.
Use Lower ISO
Try to keep your ISO setting to 100 or less. 200 if necessary. Night shots can get noisy very quickly.
But there maybe instances where higher ISO helps according to gregoryballosphoto: When some people think of taking night photographs they often think that the lower the ISO the better. While this is true in most circumstances, a super low ISO is not always the best way to take night pictures. The reason is because there are often lights that we don't think of that can cause a night shot to come out really bad if the ISO is too low. Some examples are the direct moon light, street lights, star light, city lights and car lights to name a few. If you just put your camera on the lowest ISO setting then you could end up with a really bad exposure. I usually start with an ISO of around 200 dialed in and then adjust it up or down depending on what the exposure looks like it needs. Within a couple of shots I usually get the exposure I am pleased with.
Enhancers
- One powerful visual technique in cities, is to use a long exposure during in the blue hour. This will add headlight trails to your already brightly lit neon signs, conveying a sense of motion and dynamism to the image.
- Water is a great enhancer of cityscapes, many of the worlds great cities are built on an around water. Use the water’s reflections to add texture to the scene and to lead your eye to the subject.
- As well as water, elevation is a powerful tool in the cityscape photographer’s arsenal. Getting an elevated viewpoint can create new insights on a city and add a sense of scale.
Shoot in RAW
Night scenes are particularly challenging to process, so give your self the opportunity to fix any issues your camera may have. To make my life easier I often shoot and JPEG/RAW mode so I don't have to do more work if my camera got it right the first time.