Photos are at their best at ISO 64 and 100 with very good detail and the least amount of visible noise at 100 percent. At ISO 200, photos viewed full size have noticeable noise and softening from noise reduction, but overall detail is still very good. Noise increases quite a bit at ISO 400, but the reduction isn't too heavy so you still get good enough detail for small prints. The last two full-resolution sensitivities--ISO 800 and 1,600--aren't good for much, as photos get hazy and soft along with very noisy and colors turn flat. Overall, photo quality is good outdoors, mediocre indoors, and poor in low light. In other words, it's average for its class.
Though the flexibility of the lens isn't as extreme as other megazoom models, the S1500 will get you considerably closer and the image stabilization is still effective. On the left is a shot of the Empire State Building at the lens's 33mm-equivalent widest, while the right is fully zoomed in to 396mm-equivalent position.