iPhone's Retina Display: What Is It?

Apple iPhone 4
The iPhone 4 features what Apple calls a "Retina Display.". Apple

Apple calls the display on the iPhone a "Retina Display," saying it offers more pixels than the human eye can see -- a claim that has been disputed by some experts.

The iPhone 4 was the first iPhone to come equipped with a Retina Display with a pixel density of 326ppi (pixels per inch). When announcing the phone, Apple's Steve Jobs said that 300ppi is a "magic number," because it's the limit of the human retina to distinguish pixels.

And, as the device features a display with a pixel density of more than 300ppi, Jobs claimed that text would appear clearer and smoother than ever before.

Since the launch of the iPhone 4 in 2010, every iPhone revision has sported a Retina Display, but the actual display size and resolution has been changed over the years. It was with the iPhone 5, when Apple realised that it was time to finally increase the screen size from 3.5-inches to 4-inches, and with that change came a change in resolution - 1136 x 640. Even though the company was using a higher resolution than before, the actual pixel density was kept the same at 326ppi; classifying it as a Retina Display.

However, a 4-inch display was still too small compared to smartphones produced by its competitors, they were sporting displays ranging from 5.5-5.7-inches, and people seemed to like them. In 2014, Cupertino launched the iPhone 6 and 6 Plus, it was the first time the company introduced two flagship iPhones to the world at the same time.

And, the main reason behind them was that both devices features different screen sizes. The iPhone 6 packed a 4.7-inch display with a resolution of 1334 x 740 and pixel density at 326ppi; again, keeping the pixel density exactly the same as before. But, with the iPhone 6 Plus, the company increased the pixel density - for the first time in four years - to 401ppi as it equipped the device with a 5.5" panel and resolution of Full HD (1920 x 1080).

Updated by Faryaab Sheikh