Update: May 24, 2019 at 4:25 p.m. ET: We’ve been back and forth with OnePlus about this camera topic today and it seems that a bit of a grey area in terms is getting in the way of understanding what’s really going on.
OnePlus is adamant that there’s no dishonesty on its part and that the 3x zoom provides full lossless quality. The quality part is true — there’s no digital zoom or quality degradation going on. What’s happening is that the 3x zoom reduces the field of view from the full 13MP sensor to give you an 8MP output. It’s also worth noting that OnePlus’ marketing material mentions 3x zoom at 8 megapixels, which is exactly what you get out of the camera, although the hardware is a little different.
In my opinion, the debate really comes down to what you consider an “optical” zoom and how this relates to focal length and field of view. Camera lenses are fixed in smartphones, which means that the focal length is set based on the sensor size, distance, and aperture of the lens. In the OnePlus 7 Pro, the telephoto camera used for portrait mode and zoom has a focal length appears to produce approximately a 2.2x zoom compared to the regular sensor. This focal length is dependant on the 13MP sensor size and cannot change if you switch to 8MP. However, you can make an image appear more zoomed in on a small screen, without degrading quality, by cropping or changing the field of view. This is what the OnePlus 7 Pro does.
Ultimately what you’re getting here is a crop, and that’s okay. However, I wouldn’t consider it a 3x optical zoom camera in the strictest sense. Why implement the camera this way rather than giving users a 13MP output at 2.2x and allowing them to crop in manually in photo as well as portrait mode? I’m not sure. We made a few tweaks to the original article below to better clarify these points.
Original article: May 24, 2019 at 5:58 a.m. ET: The OnePlus 7 Pro has earned praise from reviewers, but we thought photo quality was one major weak spot in our review. Now, it seems like OnePlus may have hit a bit of a grey around about its zoom capabilities.
Reddit user ImKuya discovered that there were differences when switching from portrait mode to the 3x telephoto zoom camera. The user found that portrait mode shots were zoomed out (2.2x) and at 13MP, while the 3x zoom option was indeed showing 3x zoom and at 8MP.
We can confirm this by overlaying the different camera files over one another (see below).
It’s clear that there’s a reduction in the megapixel count and the 3x zoom picture is clearly a crop of the larger 2.2x zoomed image. However, note that it’s not perfectly aligned and sized, suggesting that there’s a little more than simple cropping going on here. More on that in a minute.
The OnePlus 7 Pro telephoto camera is a 13MP sensor (SK53M5). But OnePlus advertises the telephoto camera as offering 8MP 3x optical zoom. In other words, OnePlus is using the sensor’s native 2.2x zoom factor for portraits but cropping the sensor’s output for 3x zoom. This reduces the overall pixel count of the image by reducing the field of view, but the quality between the two images is maintained.
In a statement to Android Central, the company steered clear of calling it “3x optical zoom,” saying it achieves 3x zoom with “no digital zoom or loss of detail.”
The OnePlus 7 Pro has 3x zoom with no digital zoom or loss of detail. The telephoto camera serves two main purposes: 3x zoom and portrait mode photography. It will switch the field of view depending on the camera mode. With 3x zoom, the telephoto camera delivers the advertised lossless 8 megapixels images. Portrait mode utilizes all 13 megapixels from the sensor in the telephoto camera.
Note that OnePlus doesn’t claim optical zoom in the statement, but rather “lossless 8 megapixels images.” The difference is subtle, but important. That’s despite the fact that the official OnePlus 7 Pro specs page clearly mentions optical 3x zoom.
How is OnePlus achieving lossless zoom?
So what’s going on here? According to Digital Camera World, OnePlus appears to be using a “composite of image data” from the 48MP sensor and the optical zoom lens to create its digital shots. We tested this out by looking at three pictures shot from a tripod at 2.2x, 3x, and using the portrait (bokeh) mode. The images below are all 100% crops.
Clearly, the optical zoom camera used in portrait mode produces much more detail than the main camera’s 2.2x digital zoom used in the standard photo mode. Which does make you wonder why the optical lens isn’t used at 2.2x in photo mode too. Regardless, the 3x photo mode zoom clearly preserves the original detail from the optical camera but appears to use the main camera to improve the color balance and noise. This sets it apart from technologies like Huawei’s Hybrid Zoom, which use superresolution and upscaling techniques that are very different from OnePlus’ crop.
The results are clearly pretty good, but it’s debatable whether OnePlus should be advertising the phone with 3x optical zoom or a 3x telephoto camera. Huawei generally avoids this for its phones, promoting the native zoom factor (3x or 5x) and using “hybrid zoom” branding otherwise.
It’s not the first time the firm was caught for misleading marketing, as the OnePlus 5 was advertised as having a 2x telephoto zoom camera. It later emerged that it had a 1.6x telephoto camera, using digital zoom and multi-frame capture to achieve the 2x factor. However, OnePlus isn’t pulling these tricks this time around.
In the end, the subtle distinction between optical and lossless zoom technologies doesn’t matter that much for the average consumer. Just like benchmark scores really. What does matter is the negative perception debacles like this create.