Dustin Curtis who is user interface designer has been wondering about Apple’s decision to launch iPhone 4S with the 3.5 inch screen, especially when it has been facing competition from Android based smartphones like Samsung Galaxy S II that sport a larger screen. He believes that it boils down to usability.
He writes on his blog:
When you first see a phone with a 4-inch or larger screen, it seems like a much better experience. I thought it was a technical decision, and it could be, but since switching to an Android phone — a Samsung Galaxy S II, the “best Android phone you can buy, anywhere” — 15 days ago, I have realized another huge downside of larger screens: when holding the phone with one hand, I can’t reach the other side of the screen with my thumb.
Touching the upper right corner of the screen on the Galaxy S II using one hand, with its 4.27-inch screen, while you’re walking down the street looking at Google Maps, is extremely difficult and frustrating. I pulled out my iPhone 4 to do a quick test, and it turns out that when you hold the iPhone in your left hand and articulate your thumb, you can reach almost exactly to the other side of the screen. This means it’s easy to touch any area of the screen while holding the phone in one hand, with your thumb. It is almost impossible to do this on the Galaxy S II.
There two more reasons:
- If Apple would have launched an iPhone with a bigger screen, it would have been quite a disruptive change for developers as they would have to redesign their apps for the larger screen, which is quite an obvious reason to resist changing the screen size.
- As John Gruber of Daring Fireball had pointed out last week, an increase in the screen size would have also reduced pixels-per-inch resolution beneath Apple’s own threshold to qualify as a “retina display”.
But the reason that Dustin has highlighted could have also played a major role in Apple’s decision to stick with 3.5-inch screen. We’ve always felt the size of the iPhone is just about right, anything bigger would make it uncomfortable to handle it with a single-hand. As TiPb points out Apple treats iPad as a two-handed device, iPhone as a one- or two-handed device.
It will be interesting to see if Apple decides to offer a bigger screen in future iPhones. We wouldn’t count on a 4-inch screen, though a 3.7-inch screen is probably possible with an edge-to-edge screen even if you take usability into consideration, which will occupy nearly the entire front of the phone as seen in one of the mockups below.