Pinch to zoom has become such a standard in interface interaction that I didn't question it until switching to google's map app on the iPhone. Their double click and drag behaviour is superior in that you don't need two hands.
You know something is wrong with your UI when users sometimes resort to putting their nose on the screen of their phone.
I'm not ashamed to admit that my usual tablet browsing right before bed has my left hand holding the tablet, my right hand and thumb scrolling, and sometimes my nose pushing on links.
I doubt pinch to zoom falls in that category then. The vast majority of innovative (or unique) touch based interactions/gestures have to be learnt and cannot be intuited. As you know, intuition just means your brain recognizes a pattern.
Not to defend pinch to zoom, but If you need two hands you may want to change how your holding your phone. Index and thumb on the screen, other three fingers to hold the back.
Tired that, my palm will touch the lower edge of the screen activating menu buttons. The only befit to the pinch and zoom method is the ability to rotate the map.
I've hardly ever seen people zooming with one hand (one hand on the screen, sure, but the other hand holding the phone). Maybe it works for you but, having just tried it, I find it very clumsy.
I've just looked through a load of random videos of people using their phones on youtube and I didn't see a single one where people are holding it with 3 fingers behind and two in front.
I just tried this one handed suggestion - first time ever in my 6 years using an iPhone - and I can see why I never thought of it. Extremely awkward and imprecise. I don't get why anyone would do that. Do you have giant hands?
For zooming, I've always used the double-tap method. This generally works fine for zooming in and out on Safari, and it works for zooming in on Maps. I can do a two-finger double tap on Maps to zoom out, but it's still pretty awkward so I'll keep switching to two-handed mode for those (rare) instances.
I do occasionally (meaning one hand holding, one hand doing the pinching and zooming. Not one finger from each hand doing the pinch-to-zoom). It's easier to do, and more accurate in my experience. I do pinch-to-zoom with one hand sometimes, but I find that I can't always get it right.
Ah, that's my misunderstanding. I was envisioning a finger from each hand doing the zooming. One holding + one pinching - duh, yes I do that all the time. Whoops!
Actually, I can pinch-to-zoom using my thumb and pointer-finger on the screen with my remaining three fingers holding the phone. It's awkward, but works in a pinch (haha).
I much prefer a gesture that makes intuitive sense. Pinch-to-zoom is very easy to learn and just seemed right the first time I saw it. I haven't tried the double-tap+scroll gesture you mention, but it sounds like something that would be a tad trickier and less obvious.
You seem to be saying you need two hands to pinch and zoom on an iPhone. You're doing it wrong! You should also know that something is wrong with your argument when you have to resort to fabricated anecdotes.
Pinch-to-zoom with one hand is extremely awkward, unreliable, and inaccurate. It's also a great way to drop your phone when you're standing on a crowded bus.
The root of the confusion here is that iphones are a lot smaller than most android phones. I'm holding a blackberry bold right now, and pinch with two fingers while holding the phone with three works just fine and is plenty secure.
If you're right handed: bottom right corner in the fold of your palm, supporting the back with your ring and middle fingers, and support the bottom edge with your pinky. Works fine as long as you're not gesticulating aggressively with the same hand.
Probably works for only a % of the population. I'm a guy with small hands, smaller than some women. I can't hold the phone steady, and much of the screen I couldn't possibly pinch without my palm hitting the screen.
It's like Lebron James telling you your doing it wrong when you shoot a jump shot or layup instead of dunking.
You know something is wrong with your UI when users sometimes resort to putting their nose on the screen of their phone.