how do I get night time or low light shots without sacrificing quality by ramping up the iso?
The easiest ways would be to either use a wider (smaller number) aperture or use a tripod/ put your camera on something that doesnt move.
Keep in mind however that higher ISOs don’t necessarily equate to lower quality.
A lower ISO struggling to pick up detail in the shadows will create noise, depending on the situation it can be more noise than that same picture taken at a higher ISO. Lets say you’re shooting hand held with a 50mm. You’d need your shutter speed to be at least as fast as 1/50th to (ideally) avoid camera shake. Lets say the lens you’re using is wide open at f1.8, but you want to shoot at f4 (because composition). If a properly exposed picture requires ISO 800, that picture is going to have less noise at ISO 800 than 400, assuming you keep all the other setting the same.
This is because the camera’s sensor at ISO 400 cannot find any detail in the shadows and will basically make stuff up so you get brightly colored pixels. Bump the ISO up to 800 and now the camera is able to pick up details so it doesn’t need to make anything up.
Once you have composed your picture, your next decision needs to be aperture, then shutter speed, then ISO. Use ISO to allow you to shoot at your chosen aperture and shutter speed, not the other way around, in most cases.