Comparing the iPhone 4S and 3GS Cameras

Sherree and I use our Apple iPhones a lot, and in particular the camera. The 3GS’s camera has served us well but it was never a stellar performer. The iPhone 4S features a much better camera, so that was a feature I was sure we’d both enjoy.

The first and most obvious difference to me was that the field of view is different: the iPhone 3GS has a 37mm-equivalent lens, while the iPhone 4S has a 35mm-equivalent lens. (I’m surprised to say that I noticed such a small difference so easily.) ArsTechnica has a good look at the camera improvements. Notably, the 3GS has a nondescript 3 megapixel camera with a single-element lens. The 4S has a backside-illuminated 8 megapixel camera with a five-element lens.

I wanted to do some quick tests to see just how much different and better the iPhone 4S camera was. The cropped shot above shows the 4S on the left and the 3GS on the right. I scaled the 4S photo down to set beside the 3GS photo to create this split-screen view. The difference is really stunning: the 4S side shows so much detail, and the 3GS side looks muddy, almost painted (compare the grass in the yard). Notice the detail differences in the small branches, and even the blown-out-to-white bird feeder roof edges. The white balance in the 3GS side is a little too green; something I’ve noticed about many 3GS photos taken outside. What a great leap forward!

A higher resolution camera can capture more detail, so that can also account for some of the difference. A multi-element lens will better mitigate optical aberrations such as the white blooming off of the bird feeder roof as well as just offer a sharper picture. I don’t know if these two differences account for much of the quality improvement, though some other advances likely play a key role, too. Also, in the 3GS side, the painterly effect could be overzealous jpeg compression. In the end, so many minor differences really add up to a much better photo!

Below is another cropped split-screen composited shot taken in our living room — a dark environment, and a very typical place for us to quickly pull out our phone to snap a photo of Patrick. Again, iPhone 4S on the left; 3GS on the right.

Both sides look pretty bad, though that’s what happens when shooting in such low light. The 4S is again clearly better showing more detail, more color variation, and less noise. The 4S side has less color saturation, but I suspect that’s an artifact of the 3GS trying to make bad results look better: the colors are more vibrant but there’s less variation between colors.

An interesting thing to note about this shot is that the 3GS at ISO 1000, f2.8, 1/10 sec. The 4S recorded it at ISO 800, f2.4, 1/15 sec. The 4S does have a larger maximum aperture (f2.4 vs f2.8) that is used here but the end result is effectively the same exposure. I couldn’t get the 4S to shoot at ISO 1000 for a more direct comparison, which would have likely added a bit more noise to the shot.

The iPhone 4S camera looks to be notably better. I look forward to giving it a better workout in the coming weeks.