Quattro and AFE

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Roland Karlsson
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Quattro and AFE
2 months ago

We, or at least I, have assumed that Quattro has no AFE.
That is, AFE in the meaning of Sigma vocabulary, i.e. that
the data is not amplified before stored digital.

Now - this is not the case!

I have made measurements at ISO 100, 200, 400, 800 and 1600.

I used the same aperture and exposure time and only changed ISO.

ISO 100 and 200 got exactly the same values, let us call that the base amplification.

ISO 400 had 2x base amplification, i.e. the values were twice as high.

ISO 800 and 1600 had 4x base amplification.

Somewhat confusing IMHO.

In my test image this means that the data that was intact in ISO 100-400 were actually clipped for ISO 800 and 1600.

 Roland Karlsson's gear list:Roland Karlsson's gear list
Sigma DP3 Merrill Sigma DP2 Quattro Sony Cyber-shot DSC-RX100 III Pentax K-3 Pentax smc DA 15mm F4 ED AL Limited +8 more
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