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PDAF pimples
The Fujifilm GFX100S exhibits a significant image quality defect in having off-color PDAF pimples—a made-up term, as I am guessing at the cause based on the pattern which is row-based and of definite periodicity. Hence it is a sensor-derived issue.For lack of a better term, and because of the probable genesis, for now I am calling this defect PDAF pimples, as I suspect they stem from PDAF focusing pixels.
- Pimples are seen even without any unusual raw processing parameters. They may be faint but they are there with the right subject matter. Using perfectly reasonable adjustments can make them much more obvious.
- Pimples interact with the underlying subject matter, becoming visible or not, depending (see snow below, where they are absent). I have not determined what condition(s) are required for them to manifest.
- Pimples contaminate the entire frame; it is only a matter of whether they are obvious or not.
- Pimples are seen only along lines that are 36 pixels apart (not in-between the lines). There are 242 such lines on the GFX100S sensor.
- It’s not feasible to spot them out as they number in the tens of thousands, at least.
- I don’t know if they are related to Adobe Camera Raw (choice of raw converter). But they surely are in the raw data capture and so it should only be a question of raw processing accentuating or masking them.
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