As I watched Apple announce the latest line of iPhones last week, I couldn’t help but think of the toilet paper math meme – you know, the one where photos of the packaging say that 12 = 52 but also 12 = 72.
Because, as I was looking at the specifications and photos of a rear camera system that clearly used 3 lenses, Apple said that the iPhone 17 Pro is like having “8 pro lenses in your pocket.”
Perhaps someone at Apple’s Marketing team has been in contact with someone at Charmin, because while 3 = 8 on the iPhone 17 Pro, 1 = 4 on the iPhone Air.
Even worse, Apple says the iPhone 17 Pro has the longest “optical quality zoom ever on iPhone at 8x,” yet the iPhone 16 Pro had a 5x lens on its telephoto camera, while the iPhone 17 Pro actually only has a 4x optical lens.
I may have been an English major with a deep-rooted hatred of math, but I didn’t need to suffer through pre-calc to know that something doesn’t add up here. So what’s actually going on with the iPhone 17 Pro cameras, and why is Apple claiming more lenses than are really there?
Apple’s camera math mixes the actual physical lenses that are there with the capabilities of the camera’s sensors in order to multiply the camera’s capabilities without physically adding more lenses. It doesn’t say that the iPhone Pro 17 actually has 8 lenses, but adds the all-important “like.”
Similarly, Apple doesn’t say that the iPhone 17 Pro has 8x optical zoom, but “optical-quality” zoom.
The trick to getting the look of eight lenses in three is actually in the iPhone’s sensor, not the lens.
The iPhone has used a Quad Bayer sensor on the main camera since the iPhone 14. In a standard camera sensor, each pixel has its own red, green, and blue filters that enable the sensor to see in color. But, on a Quad Bayer sensor, pixels are grouped into four, and each of those four has a different color filter, rather than using all color filters on every single pixel.
Those groups of four are key to the Quad Bayer sensor’s features, as well as the convoluted lens math Apple is using here. All 3 of the rear cameras on the iPhone 17 Pro are now 48MP Fusion Quad Bayer cameras. Because pixels are grouped into quads, the sensor can take 48MP high-resolution shots, or it can use those pixels in quads to take 12MP shots.
Mixing the lenses with those of different resolutions is how Apple is getting eight “lenses” from three on the Pro and four “lenses” from one on the Air. The 8x “optical-quality” zoom on the iPhone 17 Pro just uses the 48MP camera with a 4x optical zoom lens to crop the image in half, doubling that zoom range.
Yes, the trick to Apple’s strange lens math is using digital zoom, or cropping, rather than optical zoom. Yet Apple says this still delivers “optical-quality” zoom, so what gives?
The trick is, in part, due to that Quad Bayer Sensor. The image quality on a 48MP Quad Bayer Sensor isn’t going to be quite as good as a standard 48MP sensor because those pixels only have a single color filter. The camera fills in missing color data in the processing stage, which can make a Quad Bayer photograph look a bit more overprocessed with smoother details compared to a standard image.
When you group those four pixels together instead, using the lower resolution mode, the colors will be a bit more accurate, the details less overly processed and the grain from low light lower. So while the 8x zoom on the newly upgraded 48MP camera on the iPhone 17 Pro and Pro Max may be a crop, it’s a crop using a sensor that has some advantages when using a lower resolution mode.
The other reason Apple says the digital zoom has “optical-quality” likely has to do with the so-called Fusion camera. A Quad Bayer Sensor organizes pixels in groups of 4, and a 48MP camera divided by 4 is 12MP – not the iPhone 17’s default 24MP resolution. That’s where “Fusion” comes in. The 24MP photos are created by combining a 48MP image and a 12MP image. (DJI also uses Quad Bayer sensors.)
This all happens under the hood of the iPhone, without any input from the user. That means part of the reason that the 8x digital zoom has “optical” like quality is from computational photography, which is a term that refers to improving the quality of an image using software, rather than physical components like the lens and sensor. Computational photography is how modern smartphones balance the need to fit cameras into increasingly thinner devices.
All that boils down to one big question: Is the quality on Apple’s new digital zoom really going to look like optical zoom?
I haven’t got my hands on a new iPhone yet to test the theory. I suspect images from the 8X “optical-quality” zoom won’t be quite as good as a 48MP shot from the main camera using real optics, but may be close enough when compared to the 24MP default resolution. With the upgrade in sensor, I suspect the 4x on the new iPhone 17 Pro may even look better than the 5x telephoto lens on the previous generation.
Using that Quad Bayer digital crop, the iPhone 17 Pro’s trio of rear cameras create the look of a 13mm, 24mm, 28mm, 48mm, 100mm and 200mm lens. The eighth lens is the iPhone’s macro or close-up capabilities. Similarly, on the iPhone Air, that single camera is using the different resolutions of the camera sensor to turn a 1x lens into a 2x “lens.”
I’m less annoyed by Apple’s confusing camera math than I am about that word “pro” when Apple says the iPhone 17 Pro is like “having 8 pro lenses in your pocket.” Computational photography and the design of the Quad Bayer sensor may make the three lenses pass for eight on the lower bar for smartphone image quality, but even a smarter digital zoom isn’t going to look like a real pro lens.
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