Does the iPhone 4 really have a 'Retina Display'?

A display expert chimes in on Apple's claims and finds that, though the display is excellent, its claims might be exaggerated

Dr. Raymond Soneira runs DisplayMate Technologies, which makes software to test display quality. He also knows more about digital displays than just about anyone I know - and I know some pretty tech-savvy folks. This morning, Dr. Soneira shot me an interesting email regarding the so-called "Retina Display" of the iPhone 4. To clarify: a retina display is one whose resolution meets or exceeds the maximum resolution the human retina is capable of resolving, assuming perfect vision.

This is a bit tricky, since the eye doesn't have "pixels" and the resolution required to match the human eye's capability depends on the distance from your eye to the display. If you sit four feet away from a 50" 1080p television, you'll see pixels. If you sit 100 feet away, you won't. The distance between any two visual elements is a matter of how many pixels per "arc degree" of vision it covers. Dr. Soneira's email, in full and unedited, is as follows:

...

The iPhone 4 has an outstanding display... and I'm glad that Apple resisted the emotional rush to OLEDs because they still need lots of improvement before they will be ready to compete with the highly refined IPS LCDs. The iPhone 4 display should be comparable to the outstanding IPS LCD in the Motorola Droid, which I tested and compared to the Nexus One OLED, which was trounced by the Droid.

Steve Jobs claimed that the iPhone 4 has a resolution higher than the retina - that's not right:

1. The resolution of the retina is in angular measure - it's 50 Cycles Per Degree. A cycle is a line pair, which is two pixels, so the angular resolution of the eye is 0.6 arc minutes per pixel.

2. So if you hold an iPhone at the typical 12 inches from your eyes, that works out to 477 pixels per inch. At 8 inches it's 716 ppi. You have to hold it out 18 inches before it falls to 318 ppi.

So the iPhone has significantly lower resolution than the retina. It actually needs a resolution significantly higher than the retina in order to deliver an image that appears perfect to the retina.

It's a great display, most likely the best mobile display in production (and I can't wait to test it) but this is another example of spec exaggeration.

...

So there you have it - some math from a display expert showing that, while the iPhone 4's display is certainly exciting and probably represents a step forward for smartphones, it may fall short of Apple's claims of meeting or exceeding the resolution of the human retina.

Be sure to check out our other coverage of cell phones.

Follow Jason Cross on Twitter.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags iPhonesmartphonesiphone 4

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jason Cross

PC World (US online)
Show Comments

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Kurt Hegetschweiler

Brother PocketJet PJ-773 A4 Portable Thermal Printer

It’s perfect for mobile workers. Just take it out — it’s small enough to sit anywhere — turn it on, load a sheet of paper, and start printing.

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?