Yesterday, Sony introduced the flagship smartphone Xperia 1 IV, one of the few innovations of which was an improved telephoto. Like the previous generation, this is a variable EGF camera capable of shooting at varying degrees of magnification.
But now it increases more strongly: 3.5x-5.2x against 2.9x-4.4x in the previous one. Or, speaking in the more formal language of the EGF, 85/125 mm now versus 70/105 mm then.
It would seem that this is an obvious progress, albeit a small one – but no. Upon closer examination of the characteristics, we found that Sony actually worsened the camera, but pretended that it was even better. Now we will explain, but get ready to turn on spatial thinking.
So, what determines the camera’s capture angle? In fact, from three parameters. The first is the optical properties of the lenses, the way they scatter the collected light. Optics can collect all the light into a narrow “beam”, and then you get a wide-angle camera (wherever it comes from, it will still hit the sensor), or it can “spray” it in all directions, and then you get a telephoto (only light that fell almost exactly perpendicular to the camera, will not fly past the sensor).
This is the most “honest” way to make cameras with different viewing angles. The second way is to move the sensor further or closer from the lenses (focus points). The farther it is, the more light “flies” past it, which means that a telephoto is obtained.
And there is a third way: you can simply make the sensor smaller or larger without changing the optics. It is clear that if you put a larger sensor to the same optics, you get a wide one, and if the sensor is smaller, then a telephoto. That’s exactly what Sony did: the diagonal of the sensor in the Xperia 1 IV is 1/3.5″ versus 1/2.9″ – or, more simply, 4.8 mm versus 5.8 mm.
Thus, the sensor diagonal was reduced by 17% – and, what an incredible coincidence, the EGF increased by the same 17%. That is, the optical design has not changed in any way, but due to the reduced sensor, 17% of the light flies past, and the picture on the phone screen becomes larger.
It is clear that the “cutting off” of the sensor gives a very dubious increase in the quality of shooting, so it is not clear what exactly Sony is proud of in its new telephoto.
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