iPhone Duo zoom test — do you really need a telephoto lens?
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The iPhone Duo is an impressive phone, but we can't ignore the fact that you do have to accept a bunch of compromises . One of them is the fact that the foldable phone only offers two main cameras, and misses out on the telephoto lens you'll find on the likes of the iPhone 18 Pro Max . But does that actually matter in the long run?
We found that the loss of the telephoto lens was detrimental to the quality of zoomed in shots on the Samsung Galaxy Z Fold 8 compared to the Z Fold 8 Ultra . That doesn't bode well for the Duo, even if Apple's cameras operate very differently than Samsung's — especially on the software side of things.
So we decided to do some testing to find out exactly what the deal was, comparing the Duo to both the iPhone 18 Pro Max and the telephoto-less Galaxy Z Fold 8. Here's what we found.
Like the iPhone 18 Pro Max, the iPhone Duo has something Apple calls "optical quality 2x telephoto" capabilities. This is essentially a form of digital zoom, which takes a photo with the 48MP main camera and crops it down to 12MP — imitating magnification in the process. The main cameras aren't identical, but they are pretty close from a hardware perspective.
It's no surprise that the photo quality isn't that different at 2x magnification. There is some difference in sharpness and overall quality in the iPhone Duo's favor, as well as some over-exposure on the iPhone 18 Pro Max. But, overall, the two photos are close enough that the majority of people won't see the difference.
As for Samsung's Galaxy Z Fold 8, we can see a little more sharpness and color saturation at 2x magnification, but overall the amount of differences between the two phones are pretty meager.
The iPhone 18 Pro Max's tetraprism telephoto lens tops out at 4x optical zoom, so it's no surprise that it can take much higher-quality photos at this magnification than the iPhone Duo. That's fairly noticeable at the offset, especially if you look at the wooden pillar in the foreground, but the more you zoom in the more the quality and sharpness degrades on the Duo's photo.
The Z Fold 8 also has the slight edge when it comes to those same factors. While the iPhone 18 Pro Max still trumps Samsung's telephoto-less foldable, the level of detail captured by the Z Fold 8 at 4x zoom is noticeably better than that of the iPhone Duo.
If you up the zoom to 8x magnification, you can see that the quality difference is even more pronounced between the two iPhones. No doubt thanks to the 8x "optical quality" camera, the iPhone 18 Pro Max still offers a sharp image that captures a fairly high-quality photo.
Meanwhile, the iPhone Duo is noticeably degraded, and that's most obvious on the letters, which are starting to turn blurry and pixelated, and even starting to merge together in the case of some of the smallest lettering.
The Galaxy Z Fold 8 looks a little better than the Duo, though it is noticeably worse quality than the iPhone 18 Pro Max. The lettering and details are getting pixelated, but the details are still sharper than those captured by Apple's foldable. That's especially noticeable on the logo at the rear of the boat, which is sharper and has better-defined shapes than the fuzzier image on the iPhone Duo.
It's a very similar story at 10x magnification, and it shows just how well the iPhone 18 Pro Max's "optical quality" zoom is able to perform. The flagship's pseudo-zoom stretches to 16x magnification, and you can't really see any loss of quality at this particular level. Meanwhile, the iPhone Duo looks slightly worse than it did at 8x magnification, with slightly more visible blurring to the finer details on display.
You can see the quality start to drop on the Galaxy Z Fold 8 as well. Letters are getting fuzzy, details on the logo are even more blurred, and the grain on the wooden post in the foreground is starting to merge together. It still has a slight edge over the iPhone Duo, but it's catching up to Apple's foldable fast — which isn't a good thing.
The iPhone Duo's magnification maxes out at 10x, so we can't actually compare its capabilities further. Which is a shame, considering the iPhone 18 Pro Max extends all the way up to 40x zoom — a point in which AI plays a much bigger role in the quality of the photo in question.
The quality still holds up at 20x zoom, which is pretty incredible considering how much degradation there was on both the iPhone Duo and Galaxy Z Fold 8. Things start to get worse for wear at 40x, even with help from AI, but the damage is mostly relegated to minor blurring and pixelation on the different parts of the image.
It's not the greatest picture in the world, but it's much clearer and pleasant to look at compared to the 10x shots on the iPhone Duo and Z Fold 8.
The iPhone Duo's zoomed-in shots started off pretty strong, thanks to the 2x optical quality camera mode, but things started going downhill pretty fast. It even starts falling behind the Galaxy Z Fold 8, and while the difference isn't as large as it is with the iPhone 18 Pro Max, it does paint the iPhone Duo's zooming capabilities in a particularly bad light.
Still, it's obvious to everyone that the iPhone 18 Pro Max's zooming camera outclasses the iPhone Duo in every way. The tetraprism lens, in conjunction with up to 16x optical quality zoom, managed to maintain a high quality picture for a surprisingly long time. Which just goes to show that the telephoto lens isn't quite as frivolous as it seems — and here's hoping that the inevitable iPhone Duo 2 adds that all important third camera lens.