In an article about a new (dual camera) smartphone the following is stated:

Asus ZenFone 3 Zoom sports a dual rear camera setup, with one 12-megapixel rear camera with Sony IMX362 sensor, and f/1.7 aperture, and the other 12-megapixel rear camera featuring a 2.3x optical zoom - allowing for a total 12x zoom

Does this make any sense? The property that we have a 12x zoom is implied by two cameras and one being 2.3x zoomable? I do not see any relationship between having 12x zoom and having two cameras where one has a 2.3x zoom...


ZenFone 3 Zoom sets the new bar for mobile photography, combining two entirely new camera systems. A 12 megapixel ƒ/1.7 aperture, wide-angle lens with ASUS SuperPixel™ Technology is primed to capture everyday scenes, especially in dark environment; and a 12 megapixel 2.3x optical zoom for high-quality close-ups from farther away.

They are referring to the total range of focal length covered by the wide angle and the optical zoom lens. Their marketing doesn't know or want to use a better term than zoom. They will have to apply software interpolation to achieve settings inbetween the two lenses.

  • There is no kind of interpolation which can use two photos from two cameras to make an even image which has some intermidiate FoV. The part of image recorded inly with wide angle camera will have drastically worse detalisation, it cannot be compensated. Jan 18 '17 at 14:07
  • 3
    @EuriPinhollow Either there is no intermediate FoV available, or they have to crop and interpolate. Maybe they stitch, maybe not. Absolutely no doubt that the result is inferior to a proper zoom lens. If the two images are indeed stitched together, they might very well disguise the effect with a smooth transition.
    – bogl
    Jan 18 '17 at 14:18

I would expect the total zoom will include the digital zoom so nothing to do with the other camera.


  • One will be wide, the other a longer lens plus optical zoom. Software will differentiate. There will be digital zoom in addition. iPhone 7 plus works in a similar manner.
    – Tetsujin
    Jan 18 '17 at 11:33

Imagine if I have two lenses for my interchangeable lens cameras. One is a 10mm lens and the other is a 50-120mm lens. Both cameras have the same size sensor.

If I covered an event with each lens on one of the cameras I could claim to having 12X zoom coverage because the field of view I'm capable of capturing varies from 10mm to 120mm focal length on the same sized sensor. Of course for fields of view between 10mm and 50mm I would need to crop an image from the camera with the 10mm lens.

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