The new 8MP camera in the iPhone 4S is one of the handset’s standout features. Other than Siri, the improved camera is likely the biggest motivator for folks to upgrade to Apple’s latest smartphone.

But iPhones haven’t always sported class-leading camera hardware — it’s come a long way in 4 years. Gizmodo demonstrates this with a side-by-side comparison of photos taken with each of the 5 iPhone models…

As you can see, camera quality wasn’t really a priority for Apple with its first two smartphones. It was more of a me-too feature that helped keep its handset on par with the competition. After the iPhone 3G, however, the camera has improved with every model.

The camera in the iPhone 4S is one of the best we’ve seen in a smartphone, hands-down. It eliminates the need to carry around a second point-and-shoot camera, something you couldn’t have necessarily said about previous iPhone models. Ah, progress.