iphone 4 to another facetime-enabled iphone, ipad, ipod touch, or mac over wi-fi. 3.5-Inch retina display. Everything you see and do on iphone 4 looks amazing. That’s because the retina display’s pixel density is so high, your eye is unable to distinguish individual pixels. 5Mp isight camera with hd video recording. The 5-megapixel isight camera built into iphone 4 captures amazingly detailed images. And you can shoot video in high definition.