Camera phones get better. Point-and-shoot cameras get cheaper. Readers query. Tests must be run.
So today I shot my way around Madison Square Park with the iPhone 4S and the Canon PowerShot Elph 100 HS. I chose the 100 HS because it's exactly the type of camera whose existence camera phones like this threaten: inexpensive, with prices as low as $150, and a minimal feature set that doesn't offer any obvious advantages over the convenience of a single device with built-in communications. But it's also a decent little point-and-shoot that takes good photos for its class, and has a 4x zoom lens; the fixed focal-length lens of the iPhone is one of its big weaknesses.
Except where indicated, I left everything on automatic. I suppose that makes this a least-common-denominator comparison rather than a best-you-can get comparison, but I think that's fair given the role they play. There are some inevitable inconsistencies: the lenses have different focal lengths, and it's hard to get the stepped zoom in the 28-112mm-equivalent 100 HS to match the 35mm-equivalent focal length of the iPhone 4S camera, and therefore the angle of view covered in the scenes can be substantially different. (I'd also like to apologize for the more boring-than-usual photos.)
In the end, this exercise for me turned out to be less about the quality of the photos and videos than how comparatively annoying the point-and-shoots are to use. I had some nitpicks about the phone as a camera--I kept putting my finger over the lens and I was worried about draining the battery (therefore rendering it useless for its gazillion other tasks)--but all its flaws paled in comparison to the seriously unintelligent autofocus system in the camera.
And it's not just the 100 HS; camera AF systems almost universally lack smarts when it comes to figuring out what you want the subejct to be. But there's no reason the autofocus system in a camera phone, and that includes a bad camera phone, like the one in my otherwise excellent, should work so much better and more seamlessly than the AF system in a point-and-shoot. The iPhone's is especially good. Most of the time, it could figure out that the thing in the center of the display was the subject. Not the closest object in the lower left corner and not the grass in the background. The statue's face. The squirrel. The Flatiron building. And the iPhone was consistent about what it chose to focus on; the Canon was all over the place from shot to shot. Its tracking AF is as fickle as a cat in a roomful of laps.
I credit the iPhone's intelligent AF for its relative speediness. We quickly ran a couple of our camera performance tests on it, and its shot-to-shot time of 1.08 seconds makes it a lot faster than cameras in the PowerShot Elph 300 HS' league. It doesn't seem to refocus if it doesn't need to, which speeds up subsequent shots considerably. Of course, with a single focal-length lens, it doesn't have to think as much as a zoom camera.
On the other hand, while point-and-shoot lenses are pretty bad as a class, the iPhone camera's is worse, with atypical distortion and fringing. Apple made a big deal about it having a wide aperture at f2.4, but that seems to be its only aperture; even most snapshot cameras have at least 2 aperture settings. However, once you take that into account, its decisions--like opting for a shutter speed of 1/2900 sec to shoot a building--make a little more sense. And the decisions a camera makes can be more important than its photo quality. The iPhone frequently errs on the side of a slower shutter speed. It pays off, except in dim light or when you're shooting moving subjects. The 100 HS, on the other hand, is a little too quick to boost ISO sensitivity, resulting in a disproportionate number of photos mushy from noise reduction.
Taking all that into account, I have to declare this contest...a draw. The 100 HS has better low light performance, better images for moderately distant subjects, fewer lens-related artifacts, shallower effective depth-of-field, and fewer processing byproducts. But then there are those AF issues. They performed about the same for macro shots and video capture. And while the iPhone has a heinously bad flash--you could put someone's eye out with it--neither delivered good flash shots. I think overall I like the iPhone's white balance better, and while it blows out highlights, it's really good about opening up midtones and shadows.
However, I think it's possible that the iPhone camera can be made better by third-party apps. I don't know the extent to which app developers have access to the data coming off the sensor, but it seems like there's room here for someone to introduce better sharpening and noise-reduction algorithms, in-phone lens corrections, and some manual metering controls to really kick its photos up a notch. And that would be so much nicer than new effects filters.