OnePlus

OnePlus 7 Pro’s telephoto lens isn’t technically 3x optical zoom, relies on crop

Damien Wilde | May 24 2019 - 5:20 am PT

The OnePlus 7 Pro does genuinely offer a step up in the camera department but it appears that the claims of 3x telephoto zoom is not actually 100% true. Digging by /u/ImKuya over on Reddit (via Android Police) has found that the OnePlus 7 Pro telephoto camera only has a 2.2x optical zoom capability.

Instead, the OnePlus 7 Pro camera uses this 2.2x optical zoom and then crops to create 3x zoomed in pictures. This effectively gives you 3x zoom but lacks the field of view associated with a true 3x telephoto zoom lens. We have to admit, that is a little bit sneaky all things considered.

This little bit of digging has found that the OnePlus 7 Pro uses the telephoto zoom lens for the in-built camera portrait modes. Users noticed that the field of view when in portrait mode is very noticeably wider than when using the 3x zoomed in mode — using the same telephoto lens.

Delving into photo EXIF data, you can see the resolution and focal length used by the camera for photo-taking. This is what has helped unearth OnePlus’ little white lie. The 13-megapixel image is being cropped down to just 8-megapixels to hit that 3x field of view.

So why is this a big deal? Well, it’s all to do with effective focal length and crop factors — something I’ve personally had to deal with using the Micro Four Thirds camera system extensively. Distance from your subject directly affects perspective.

In the most basic terms possible, the difference between 2.2x and 3x zoom in 35mm-equivalent focal length for the sensor is the perspective end result. AP did the math and calculated that the real focal length of the lens is actually ~57mm (2.2x) versus the ~78mm (3x) focal length advertised by OnePlus. In practice, this 21mm discrepancy doesn’t sound like a great deal, but the end result can be pretty noticeable.

This real-world focal length discrepancy affects photographic angles, meaning objects within your images will appear thinner or more warped than at the relative focal length. Cropping in doesn’t account for these angular changes and even if you are the same distance from a subject, the result can be wildly different. You can’t achieve the same effect simply by cropping in to attempt to replicate the same focal length.

The perspective remains the same, i.e. a 25mm lens can be cropped replicate a 50mm lens but the end result will still have the 25mm perspective. Your field of view will be wider which is why the results vary so much between focal lengths. Camera experts Fstoppers have an excellent guide on focal length and crop factors that you should check out to get a clearer picture of how these principles affect photography — and videography.

OnePlus gave this explanation to Android Police for the lack of a ‘real’ 3x telephoto zoom lens on the OnePlus 7 Pro:

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.

It’s also worth noting that for most people, this isn’t a cause for concern. You’ll still get the 8MP 3x zoom that OnePlus does advertise, even if the marketing used is slightly misleading. The lens itself offers 2.2x optical zoom with the 13MP sensor, while the remainder of the 3x is handled by cropping the image to an 8MP photo.