Haven't read that article, but yeah, seems they're referring to an f2.8 lens. They also note a maximum ISO of 1000, while I've taken numerous photos with EXIF data indicating ISO 2000.
Either the EXIF data on my iPhone's photos is incorrect, or the author of that article may have some inaccurate information.
Not sure how much faith I can place on the author overall. I noticed he mentions low light photos are "noisy as heck." I'm assuming he's not expecting the iPhone 4 to have low light capabilities comparable to his $1500 Canon 7D DSLR. A knowledgable photographer should appreciate the fact that a less noisy image is not always a better image. For example, Canon's latest G11 and S90 cameras boast great low light capabilities for their class. However, it's been noted that they achieve this in part by applying an excessive level of noise reduction at high ISO settings. The result is a smoother looking, noise free image, but one where much of the picture detail has been obliterated by the noise reduction algorithm, yielding less useful resolution than some competing cameras. One photo site tested further by taking the RAW version of the image (without noise reduction) and applying some careful post processing to increase sharpness. The result was a noisier image which retained far greater picture detail.
Let's not forget that in pre-digital days, ISO 400 film produced what would be considered pretty grainy images by today's standards, yet that didn't keep those images from winning awards or gracing the pages of prominent photo magazines.
Ultimately, which photo is best is a somewhat subjective matter, but most pros would take a detailed, noisy image over a noise free image that lacks detail. I consider excessive noise reduction as a sign of a marketing decision aimed at pleasing inexperienced camera buyers. I applaud Apple's decision to allow the iPhone's camera to show off its true resolving power at high ISO settings without resorting to consumer-pleasing noise reduction settings that yield inferior images. This is in line with their decision to offer a lower resolution camera sensor rather than cramming in a higher density, higher resolution sensor that looks great on the spec sheet but performs poorly in low light.