ISO 800 can be enough for night photography, but it depends on the scene and the result you want. Exposure is controlled by available light, shutter speed, aperture, and ISO. If your subject is static, ISO 800 may work fine with a longer exposure or added light. If the subject is moving, or you need a fast shutter speed, higher ISO can help—but it also increases noise.

A very high ISO is not automatically better. On some cameras, high ISO settings are more marketing than real image quality. Sensor size, pixel size, and image processing all affect low-light performance, so ISO numbers are not directly comparable between phones and larger cameras.

For night scenes, you also do not always want the image to look bright like daytime. Letting the scene stay dark can produce a more natural night look without needing extreme ISO.

In short: ISO 800 is usable, especially for static scenes, intentional dark mood, tripod/steady support, or extra light. If you need clean images of fast action in very low light, a camera with better low-light capability may help more than just a bigger ISO number.