High ISO noise has been a problem going back to the days of film. Although contemporary digital cameras outperform their film counterparts in this area, noise remains an issue when pushing settings above the ISO 1600 mark with most digital cameras; the exception is the best professional cameras available that perform well at higher settings.
To be fair, even entry-level cameras are excellent performers these days, but even so, there will inevitably be times when you need to crank up the ISO to be able to expose correctly when shooting handheld in low light or to freeze subject movement in certain situations. One thing to always
