>>1255719The 50/1.8 has a wide aperture, which lets in more light, therefore you can take better pictures in the dark, but the 50mm on a crop sensor is very narrow and not really ideal for a street photography enviroment, it's basically a near telephoto lens. you'd do better with a wide angle lens and a tripod, unless your plan is to shoot people on the street at night, for that i'd recommend a sigma 30mm f/1.4 which is basically a fast normal prime for APS-C, ideal for street photography and fast (albeit soft) enough to get some ISO800 shots at maybe 1/60th in dusk type of lighting.
Also unless you want to shoot stars, the best time for "night" photography is around dusk, just after sunset when the balance between artificial light and the ambient light is just perfect.
That milkyway picture seems photoshopped but i guess you might be able to get that kind of pic with an extreme wide angle lens, talking 14mm type of stuff on fullframe, probably can't get that wide on crop unless it's a fisheye. Also seems the ground was exposed differently from the sky and combined later in post. Sky is probably something like ISO800-1600 for probably under 15sec on a fast lens, f/2.8 or less. Ground was probably exposed with lower ISO and smaller aperture (f/8 maybe, just so he could get enough depth of field) and a long exposure, maybe up to a few minutes. (unlike the sky the earth isn't moving)
You pretty much need to keep sky exposures less than 15s or you'll get visible star trails. Although it varies by focal length, longer lens means star trails will become visible faster. 15s pretty much the limit on around 28mm (or equivalent, like 18mm on APS-C).