Display:

4-inch (diagonal) widescreen display with Multi-Touch IPS technology
Retina display
1136-by-640-pixel resolution at 326 pixels per inch
800:1 contrast ratio (typical)
500 cd/m2 max brightness (typical)
Fingerprint-resistant oleophobic coating

Camera, Photos, and Video:

5-megapixel iSight camera
Autofocus
Tap to focus video or still images
Backside illumination
Hybrid IR filter
Five-element lens
LED flash
ƒ/2.4 aperture
Face detection
Panorama
HDR
HD video recording (1080p) up to 30 frames per second with audio
FaceTime HD camera with 1.2MP photos and HD video (720p) up to 30 frames per second
Video stabilization
Tap to control exposure for video or stills
Photo and video geotagging over Wi-Fi