High ISO settings are generally used in low light situations – however the cost is digital noise (grainy looking files). So goes common wisdom. It's clear that technology is advancing and it's never too late to play catch up with what high ISOs can do for you. High ISO photography works safely in situations where bright lights (artificial) meet the night. In other words, just because the ISO is 1600 doesn’t mean you see more noise (especially true for the latest digital cameras). As long as you don't underexpose you can get good results with even older cameras (if your histogram is dipping equally to the right, you're probably getting the right exposure). The lesson here? Don't be afraid of digital noise. Think differently: High ISO photography may lend itself to your producing the best images you've ever made plus independently it is a compelling technology to follow, even for daytime use.
High ISO photography (shot at 1600 ISO). photo: (c) 2012 roberta fineberg | South Street Seaport