Boosted by Apple’s “tetraprism” technology, the iPhone 15 Pro Max gets a 5x telephoto camera that should help improve photography for those who buy the $1,199 smartphone. It’s the newest example of periscope camera designs that are spreading across flagship phones.
If you don’t know about periscope cameras, we’re here to explain it. In short, a periscope camera uses clever engineering to pack a bulky telephoto lens into a compact smartphone body so you can take photos of distant subjects like mountains or musicians. They’re key to the effort to gradually reproduce the framing flexibility of conventional cameras’ zoom lenses.
Cameras are the most important feature in most phones, as evidenced by the amount of time manufacturers devote to detailing the new abilities during each launch event and the profusion of lenses sprouting from the backs of new models. Taking photos and videos is one of the most personally important uses of our phones.
Apple announced the camera technology at its iPhone 15 launch event Tuesday. The iPhone 15, 15 Plus and 15 Pro all got camera improvements compared to their 2022 predecessors, but only the iPhone 15 Pro Max gets the new tetraprism-based periscope design.
More from the Apple event
Here’s a look at periscope cameras and why they’re a good fit for flagship phones.
Why did Apple add a periscope camera to iPhones?
The main reason is to provide iPhone customers with better photography options. The secondary reason is to catch up to the competition.
For iPhone photography, a 5x optical zoom — the equivalent of a 120mm lens on a conventional full-frame DSLR or mirrorless camera — is good for lots of situations. Telephoto cameras are useful for photographing people who are a bit farther away, like kids at a playground or Taylor Swift away on a stage. Nature and landscape photography also benefits from better telephoto reach.
The iPhone 14 Pro camera suite comes with a 3x zoom telephoto, the equivalent of a 77mm lens on a DSLR camera. That’s useful, but it falls well short of the 5x camera on Google’s Pixel 7 Pro or the 10x camera on the Samsung Galaxy S23 Ultra. The iPhone is competitive (and taking market share away from Android rivals), but its telephoto photography has been a competitive weak point.
How do periscope cameras work?
The basic problem with telephoto cameras is that they require physically longer lens assemblies. There’s no easy way around these limits of optics, physics and engineering.
Periscope cameras, also called folded cameras, work by building much of this length sideways inside the phone body. The outside lens looks like that of a regular phone camera, but behind it is a prism or mirror that bounces light 90 degrees. A 2016 Apple patent for a “folded telephoto camera lens system” shows both options.
Prisms are angled transparent blocks of glass or plastic that’ve been used for decades in optical equipment, for example binoculars or the pentaprisms in SLR cameras’ viewfinders. High-quality prisms don’t degrade image quality much.
Apple takes a different approach from Android periscope cameras. Its tetraprism bounces light not once but four times, letting the company put the image sensor in the same plane as all the other cameras sensors. That’s probably better for accommodating the electronics around a sensor, such as the image stabilization system that Apple built in to counteract hand shake or camera movement.
Today’s periscope cameras offer 5x zoom, the equivalent of about a 120mm focal length on a traditional camera. But by using just the central pixels on a high-resolution image sensor, Google’s Pixel 7 Pro also can shoot at 10x zoom, about 240mm, without any digital magnification trickery.
How do periscope cameras compare to traditional cameras?
A periscope camera gives you better zoom, but don’t expect to match what serious photographers can do with a traditional camera and modest telephoto lens, much less a $13,000, 7-pound supertelephoto lens that’s hard to fit in your backpack. In my use, I’ve found the Pixel 7 Pro’s 5x and 10x modes useful for identifying birds, for example, but not for producing particularly good photos of them.
The reason for the limit: Periscope cameras still have relatively small image sensors that struggle with lower light. Bigger sensors offer higher image quality, but they cost more, and the bigger the sensor, the bigger and more expensive the accompanying lens assembly.
We haven’t yet seen test photos from Apple’s new 5x camera, so it’s hard to evaluate whether it’ll do better than rivals when it comes to image stabilization, low-light performance, the suppression of lens flare and other optical matters.
One problem with periscope cameras is that they can displace useful medium-telephoto cameras. Samsung’s Galaxy S23 Ultra solves this problem by including an entire 3x conventional camera along with the 10x periscope. Higher-resolution image sensors like those in the Pixel 7 and iPhone 14 Pro offer 2x modes that compensate. More unusually, Sony’s Xperia 1 V phone has a true zoom reaching continuously from 3.5x to 5.2x zoom.
The larger main camera sensor in the iPhone 15 Pro also helps here. Both of Apple’s iPhone 15 Pro models will be able to shoot at designated 24mm, 28mm, 35mm and 48mm modes. With that and periscope cameras, flagship smartphones year by year come closer to traditional cameras’ zoom flexibility.