You can read official features of Lumia 730 display below.
Display colours: TrueColor (24-bit/16M)
Display technology: OLED, ClearBlack
Pixel density: 316 ppi
Display features: Brightness control, Refresh rate 60 Hz, Sunlight readability enhancements, Corning® Gorilla® Glass 3, Easy to clean, High brightness mode, Wide viewing angle, Scratch resistant glass. Touch screen technology: Super sensitive touch
So, in this video, we tried to test outdoor or sunlight readability of Lumia 730 display and check how easy it is to use outdoors on a bright sunny day. The video shows that it has great sunlight readability and usability outdoors.