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ISO calibration between cameras
  • flashflash

    Hello,

    I noticed a huge difference with ISO calibration from A7S and X5R (Dji camera). The X5R at 800 ISO is sensitively practically same than A7S at 3200 ISO

    This is not the first time I noticed an ISO sensibility difference between cameras. But this is the first time I see a small sensor does as well as a large sensor with less ISO.

    If you have an explanation you are welcome !

  • 3 Replies sorted by
  • NZVERGENZVERGE

    Well the difference between F1.7 and F2.8 is first thing worth mentioning. Ignoring the total light hitting the sensor (due to a big difference in image circle required between sensors). The actual lux (light/area) at the sensor surface is significantly higher at F1.7 and approx 3x more than at F2.8. Light transmission is also different between lenses. A lens might be F2.8 but have a transmission equivalent aperture of F3.1 (also called T3.1) for example which is very common. The difference between a T1.8 lens and T3.1 lens is close enough to 2 stops, or an ISO of 800 vs 3200 to compensate. This is what you would expect to see under the same circumstances you tested and what your video shows.

    I think you will find the X5R at 3200 ISO quite a different machine against the A7S ;)

  • yskuntoyskunto

    Could you calculate the whole system price to get the price performance ratio? May be it is cheaper to have X5 1.7 at ISO 800 compared to 7S 2.8 at ISO 3200

  • flashflash

    @NZVERGE Yes the X5R at ISO 3200 is not good as A7S. But the new Dji camera X5S do a better job at higher ISO than 800. In any case, thank you for your answer.

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