Retina display

This article is about the high-PPI screens of Apple products. For the heads-up-display technology, see Virtual retinal display.

Part of the Retina display on an iPhone 4. The pixels are not visible at normal viewing distance, creating an impression of sharp, print-like text.

Part of the non-Retina display on an iPhone 3GS. The pixels are visible at normal viewing distance.

Retina display is a branded series of LCDs and OLED displays by Apple Inc. that have a higher pixel density than traditional displays. Apple has registered the term "Retina" as a trademark with regard to computers and mobile devices with the United States Patent and Trademark Office and Canadian Intellectual Property Office. The applications were approved in 2012 and 2014, respectively.

The Retina display debuted in 2010 with the iPhone 4 and the iPod Touch (4th Generation), and later the iPad (3rd generation) where each screen pixel of the iPhone 3GS, iPod touch (3rd generation), and iPad 2 was replaced by four smaller pixels, and the user interface scaled up to fill in the extra pixels. Apple calls this mode HiDPI mode. In simpler words, it is one logical pixel that corresponds to four physical pixels. The scale factor is tripled for devices with even higher pixel densities, such as the iPhone 6 Plus and iPhone X. The advantage of this equation is that the CPU "sees" a small portion of the data and calculates the relative positions of each element, and the GPU renders these elements with high quality assets. The goal of Retina displays is to make the text and images being displayed crisper.

The Retina display has since expanded to most Apple product lines, such as Apple Watch, iPhone, iPod Touch, iPad, iPad Mini, iPad Air, iPad Pro, MacBook, MacBook Air, MacBook Pro, iMac, and Apple's computer monitors such as the Studio Display and Pro Display XDR, some of which have never had non-Retina displays. Apple uses various marketing terms to differentiate between its LCD and OLED displays having various resolutions, contrast levels, color reproduction, or refresh rates. It is known as Liquid Retina display for the iPhone XR, iPad Air 4th Generation, iPad Mini 6th Generation, iPad Pro 3rd Generation and later versions, and Retina 4.5K display for the iMac.

Apple's Retina displays do not have a fixed minimum pixel density, but vary depending on and at what distance the user would typically be viewing the screen. Where on smaller devices held or worn closer to the user’s eyes, such as watches and phones, the displays must have very high pixel density for the pixels to be indiscernible to the user, for displays viewed from farther away, such as those of notebook or desktop computers, slightly less pixel density is required in order to achieve the same angular resolution. Later products have had additional improvements, such as an increase in the screen size, contrast ratio, or pixel density. Apple has used names such as Retina HD display, Retina 5K display, Super Retina HD display, Super Retina XDR display, and Liquid Retina display for various iterations.

Rationale

See also: Fovea centralis § Angular size of foveal cones

When introducing the iPhone 4, Steve Jobs said the density of pixels needed for a Retina display is about 300 PPI (120 dot/cm) for a device held 10 to 12 inches (25 to 30 cm) from the eye. One way of expressing this angular pixel density is in units of pixels per degree (PPD) which takes into account both the pixel density of a screen and the distance from the screen to the observer. Based on Jobs' stated angular density of 300 DPI at 10–12 inches, the threshold for a Retina display is an angular pixel density of 52–63 PPD. 58 PPD, the value at 11 in (28 cm), means that a tall skinny triangle with a height equal to the viewing distance and a top angle of one degree will have a base on the device's screen that covers 58 pixels. Note that, unlike absolute linear or planar resolution (e.g. 1920×1080 pixels) or linear pixel density (e.g. 401 PPI), angular pixel density is not an intrinsic property of a display but is dependent on the distance from which it is observed; moving the eye closer to the display reduces the angular pixel density of the image (i.e. it’s easier to see detail up close), and moving away increases the angular pixel density, in direct proportion to the distance. Angular pixel density can be calculated by the formula

$2dr\tan(0.5^{\circ })$

where $d$ is the distance between the screen and observer, and $r$ is the absolute pixel density of the screen in pixels per unit length.

In practice, thus far Apple has converted a device's display to Retina by doubling the number of pixels in each direction, quadrupling the total resolution. This increase creates a sharper interface at the same physical dimensions. The only exceptions to this have been the iPhone 6 Plus, 6S Plus, 7 Plus, and 8 Plus, which render their images at triple the number of pixels in each direction, before down-sampling to 1080p resolution.

Models

The displays are manufactured worldwide by different suppliers. Currently, the iPad's display comes from Samsung, while the MacBook Pro and iPod Touch displays are made by LG Display and Japan Display Inc. There was a shift of display technology from twisted nematic (TN) liquid-crystal displays (LCDs) to in-plane switching (IPS) LCDs starting with the iPhone 4 models in June 2010.

Apple markets the following devices as having Retina, Retina HD, Liquid Retina, Liquid Retina XDR, Super Retina HD, Super Retina XDR, Ultra Retina XDR or Retina 4K, 5K or 6K displays:

Model	Marketing name	Screen size	Resolution	Aspect Ratio	Pixel density		Pixel size (μm)	Angular pixel density (px/°; at typ. distance)	typ. viewing distance	Total pixels
					ppi	px/cm
Apple Watch 38mm	Retina display	1.34 in (34 mm)	272×340	4:5	326	128	77.9	56.9	10 in (25 cm)	00,092,480
Apple Watch 42mm (Series 0, 1, 2 and 3)		1.53 in (39 mm)	312×390							00,121,680
Apple Watch 40mm		1.55 in (39 mm)	324×394		330	130	76.9	57.7		00,127,656
Apple Watch 41mm		1.69 in (43 mm)	352×430							00,151,360
Apple Watch 44mm		1.76 in (45 mm)	368×448							00,164,864
Apple Watch 42mm (Series 10)		1.77 in (45 mm)	374×446							00,166,804
Apple Watch 45mm		1.90 in (48 mm)	396×484							00,191,664
Apple Watch Ultra		1.94 in (49 mm)	410×502		335	132	75.9	58.5		00,205,820
Apple Watch 46mm		1.96 in (50 mm)	416×496		330	130	76.9	57.7		00,206,336
iPhone 4, 4S and iPod Touch 4		3.5 in (89 mm)	960×640	2:3	326	128	77.9	56.9		00,614,400
iPhone 5, 5C, 5S and SE 1, iPod Touch 5, 6 and 7		4.0 in (100 mm)	1136×640	9:16						00,727,040
iPhone 6, 6S, 7, 8, SE 2 and SE 3	Retina HD display	4.7 in (120 mm)	1334×750							01,000,500
iPhone 6 Plus, 6S Plus, 7 Plus and 8 Plus		5.5 in (140 mm)	1920×1080		401	158	63.4	70.0		02,073,600
iPhone XR and 11	Liquid Retina display	6.1 in (155 mm)	1792×828	6:13 (9:19.5)	326	128	77.9	56.9		01,483,776
iPhone 12 Mini and 13 Mini	Super Retina XDR display (Super Retina HD on iPhone X, XS and XS Max)	5.4 in (140 mm)	2340×1080		476/337	187/133	53.4	83.1		02,527,200
iPhone X, XS, and 11 Pro		5.8 in (150 mm)	2436×1125		458/324	180/127	55.4	79.9		02,740,500
iPhone 12, 12 Pro, 13, 13 Pro and 14		6.1 in (155 mm)	2532×1170		460/325	181/128	55.2	80.3		02,962,440
iPhone 14 Pro, 15, 15 Pro and 16			2556×1179							03,013,524
iPhone 16 Pro		6.3 in (160 mm)	2622×1206							03,162,132
iPhone XS Max and 11 Pro Max		6.5 in (165 mm)	2688×1242		458/324	180/127	55.4	79.9		03,338,496
iPhone 12 Pro Max, 13 Pro Max and 14 Plus		6.7 in (170 mm)	2778×1284							03,566,952
iPhone 14 Pro Max, 15 Plus, 15 Pro Max and 16 Plus			2796×1290		460/325	181/128	55.2	80.3		03,606,840
iPhone 16 Pro Max		6.9 in (175 mm)	2868×1320							03,785,760
iPad Mini 2, 3, 4 and 5	Retina display	7.9 in (200 mm)	2048×1536	3:4	326	128	77.9	85.3	15 in (38 cm)	03,145,728
iPad 3, 4, 5 and 6, Air 1 and 2, Pro 9.7"		9.7 in (250 mm)			264	104	96	69.1
iPad 7, 8 and 9		10.2 in (260 mm)	2160×1620							03,499,200
iPad Pro 10.5" and Air 3		10.5 in (270 mm)	2224×1668							03,709,632
iPad Pro 12.9" (1 and 2)		12.9 in (330 mm)	2732×2048							05,595,136
iPad Mini 6 and 7	Liquid Retina display	8.3 in (210 mm)	2266×1488	2:3	326	128	77.9	85.3		03,371,808
iPad 10, iPad Air 4, 5 and 6		10.9 in (280 mm)	2360×1640	7:10	264	104	96	69.1		03,870,400
iPad Pro 11" (1, 2, 3 and 4)		11.0 in (280 mm)	2388×1668							03,983,184
iPad Pro 12.9" (3 and 4), iPad Air 13"		12.9 in (330 mm)	2732×2048	3:4						05,595,136
iPad Pro 12.9" (5 and 6)	Liquid Retina XDR display
iPad Pro 11" (5)	Ultra Retina XDR display	11.1 in (280 mm)	2420×1668	7:10						04,036,560
iPad Pro 13"		13.0 in (330 mm)	2752×2064	3:4						05,680,128
MacBook 12"	Retina display	12.0 in (300 mm)	2304×1440	16:10	226	89	112	78.9	20 in (51 cm)	03,317,760
MacBook Air 13" and MacBook Pro 13"		13.3 in (340 mm)	2560×1600		227			79.2		04,096,000
MacBook Pro 15"		15.4 in (390 mm)	2880×1800		221	87	115	77.1		05,184,000
MacBook Pro 16"		16.0 in (410 mm)	3072×1920		226	89	112	78.9		05,898,240
MacBook Air 13"	Liquid Retina display	13.6 in (350 mm)	2560×1664		224	88	113	78.2		04,259,840
MacBook Air 15"		15.3 in (390 mm)	2880×1864							05,368,320
MacBook Pro 14"	Liquid Retina XDR display	14.2 in (360 mm)	3024×1964	14:9	254	100	100	88.7		05,939,136
MacBook Pro 16"		16.2 in (410 mm)	3456×2234							07,720,704
iMac Retina 21.5"	Retina 4K display	21.5 in (550 mm)	4096×2304	16:9	219	86	116	76.4		09,437,184
iMac Retina 24"	Retina 4.5K display	23.5 in (600 mm)	4480×2520							011,289,600
iMac Retina 27", iMac Pro and Studio Display	Retina 5K display	27.0 in (690 mm)	5120×2880		218			76.1		014,745,600
Pro Display XDR	Retina 6K display	32.0 in (810 mm)	6016×3384							020,358,144

Reception

Reviews of Apple devices with Retina displays have generally been positive on technical grounds, with comments describing it as a considerable improvement on earlier screens and praising Apple for driving third-party application support for high-resolution displays more effectively than on Windows. While high-dpi displays such as IBM's T220 and T221 had been sold in the past, they had seen little take-up due to their cost of around $8400.

Reviewing the iPhone 4 in 2010, Joshua Topolsky commented:

"to our eyes, there has never been a more detailed, clear, or viewable screen on any mobile device. Not only are the colors and blacks deep and rich, but you simply cannot see pixels on the screen…webpages that would be line after line of pixelated content when zoomed out on a 3GS are completely readable on the iPhone 4, though the text is beyond microscopic."

Former Microsoft employee Bill Hill, an expert on font rendering, offered similar comments:

That much resolution is stunning. To see it on a mainstream device like the iPad—rather than a $13,000 exotic monitor—is truly amazing, and something I've been waiting more than a decade to see. It will set a bar for future resolution that every other manufacturer of devices and PCs will have to jump.

Writer John Gruber suggested that the arrival of Retina displays on computers would trigger a need to redesign interfaces and designs for the new displays:

The sort of rich, data-dense information design espoused by Edward Tufte can now not only be made on the computer screen but also enjoyed on one. Regarding font choices, you not only need not choose a font optimized for rendering on screen, but should not. Fonts optimized for screen rendering look cheap on the retina MacBook Pro—sometimes downright cheesy—in the same way they do when printed in a glossy magazine.

Detractors

See also: Fovea centralis § Angular size of foveal cones

Raymond Soneira, president of DisplayMate Technologies, has challenged Apple's claim. He says that the physiology of the human retina is such that there must be at least 477 pixels per inch in a pixelated display for the pixels to become imperceptible to the human eye at a distance of 12 inches (305 mm). Astronomer and science blogger Phil Plait notes, however, that, "if you have [better than 20/20] eyesight, then at one foot away the iPhone 4S's pixels are resolved. The picture will look pixelated. If you have average eyesight [20/20 vision], the picture will look just fine... So in my opinion, what Jobs said was fine. Soneira, while technically correct, was being picky." The retinal neuroscientist Bryan Jones offers a similar analysis of more detail and comes to a similar conclusion: "I'd find Apple's claims stand up to what the human eye can perceive."

Apple fan website CultOfMac hosts an article by John Brownlee who incorrectly stated that the resolution the human eye can discern at 12 inches is 900 PPI, concluding "Apple's Retina Displays are only about 33% of the way there." On the topic of 20/20 vision, Brownlee misrepresented visual acuity in the population saying "most research suggests that normal vision is actually much better than 20/20" when in truth the majority have worse than 20/20 vision, and the WHO considers average vision as 20/40. Brownlee also stated that people do not always view displays at a constant distance, and claimed a close-viewed display could no longer be classed as Retina. However, near visual acuity is usually poor due to presbyopia in nearly everyone over 40, such that decreasing reading distance can actually reduce perceivable resolution.

Competitors

The first smartphone following the iPhone 4 to ship with a display of a comparable pixel density was the Nokia E6, running Symbian Anna, with a resolution of 640 × 480 at a screen size of 62.5mm. This was an isolated case for the platform however, as all other Symbian-based devices had larger displays with lower resolutions. Some older Symbian smartphones, including the Nokia N80 and N90, featured a 2.1 inch display at 259 ppi, which was one of the sharpest at the time. The first Android smartphones with the same display - Meizu M9 was launched a few months later in beginning of 2011. In October of the same year Galaxy Nexus was announced, which had a display with a better resolution. By 2013 the 300+ ppimark was found on midrange phones such as the Moto G. From 2013 to 2014, many flagship devices such as the Samsung Galaxy S4 and HTC One (M8) had 1080p (FHD) screens around 5-inches for a 400+ PPI which surpassed the Retina density on the iPhone 5.

The second major redesign of the iPhone, the iPhone 6, has a 1334 × 750 resolution on a 4.7-inch screen, while rivals such as the Samsung Galaxy S6 have a QHD display of 2560 × 1440 resolution, close to four times the number of pixels found in the iPhone 6, giving the S6 a 577 PPI that is almost twice that of the iPhone 6's 326 PPI. The Sony Xperia Z5 Premium launched in late 2015 had 806 PPI. The larger iPhone 6 Plus features a "Retina HD display", which is a 5.5-inch 1080p screen with 401 PPI.

Aside from resolution, all generations of iPhone Retina displays receive high ratings for other aspects such as brightness and color accuracy, compared to those of contemporary smartphones, while some Android devices such as the LG G3 have sacrificed screen quality and battery life for high resolution. Ars Technica has suggested the "superfluousness of so many flagship phone features—the move from 720p to 1080p to 1440p and beyond...things are all nice to have, but you’d be hard-pressed to argue that any of them are essential". Furthermore, developers can better optimize content for iOS due to Apple's few screen sizes in contrast to Android's wide display format variations.

Many Windows-based Ultrabook models have offered 1080p (FHD) screens standard since 2012 and often QHD or QHD+ as optional upgrade displays.

See also

• Resolution independence
• Pixel density
  • HiDPI
• Pixelplus