Blue-hour cityscape

The constraint is balance: for a brief window after sunset, the sky is dark enough for city lights to register but still bright enough to keep colour and detail, so neither blows out. Put the camera on a tripod, shoot aperture priority at f/8 for front-to-back sharpness, and keep ISO 100 for the cleanest file — the resulting one-to-four-second exposure is no problem on a stable base. The ultra-wide 10-20mm takes in the sweep of the skyline; a two-second timer keeps your finger off the camera during the exposure.

Watch out for missing the window — blue hour lasts only twenty minutes or so, so arrive early, compose in the light, and be ready before the colour peaks. Check the histogram, not the bright rear screen, which lies in the dark: let the lights approach but not pile against the right edge, and protect that glow the way you would any highlight.