So I may be missing something but I cannot think what it can be.

I have a Sony compact hx9v and an NEX-6. the 16mm on the NEX is very similar to the compact at its widest, so I thought I would compare the shots. With the bigger sensor I thought the NEX would produce a brighter picture.

Both 16 megapixels Both set to f3.5, ISO 100, 1/80, exp 0.

Even with this, the compact produces a brighter picture. I thought that with the bigger sensor the NEX would produce a brighter picture?

  • 1
    Can you post the two examples?
    – mattdm
    Dec 28 '13 at 15:23

It is not. What you are referring to is sensitivity to light. That is the ISO sensitivity is for and while there is a standard that describes it, digital sensors do not match exactly the posted sensitivity. A site like DxOMark actually measures ISO equivalence as part of its sensor benchmarks and you can commonly see a difference of ±1/3 EVs.

The other independent variable here is that you may be looking at images rather than RAW data. If this is the case, the tone-curve applied to transform the sensor's linear-response can be different and it most likely is. Nearly all cameras have parameters which affect , this, like Contrast, Key and Brightness. Exact parameters and their impact is different between cameras so you cannot simply set them to the same levels and expect the same results.


Theoretically both images should be the same brightness, even though the NEX sensor is larger, it stills receives same amount of light per unit area both lenses were set to f/3.5. The difference in brightness is due to different processing, there's nothing in the ISO standard that guarantee the same digital brightness values given the same exposure and ISO setting.

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