When I am working in Photoshop and zoom out on the image it gets really noisy at quality gets quite low but when you zoom in enough to work it smooths its out get back's to normal quality. I was looking at preferences settings to find the reason but nothing really worked.
Photoshop Zooming is done for performance speed not done by using slow best good interpolation. The only time your viewing you images actual pixels is when the zoom level is 100% actual pixels. Everything else you see is a quick scaling not the best image posible.