Panasonic engineering blooper

Started Feb 13, 2007 | Discussions thread
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John Sheehy Forum Pro • Posts: 21,042
Panasonic engineering blooper

I've had my Panasonic FZ50 for about 10 days. Last night I put it through one of my tests; take a shot in manual mode, well-exposed at ISO 1600, and then keep taking the same shot as I lower the ISO to 100, leaving the Av and Tv values fixed. With my Canon DSLRs, the images get worse as I lower the ISO. With a camera that just faked all the other ISOs than the lowest with multiplication or bit shifting, I would expect them all to be about the same. Not so for the FZ50; the images get better as I lower the ISO; even after scaling the RAW data 16x, the ISO 100 still has a blacker black, and weaker noise in the RAW data (and in an ACR conversion, as well). The only disadvantage of ISO 100 under-exposed 4 stops is that there are a very small number of hot pixels (automatically removed by many converters), which are not hot in any other images, which I assume to mean that they are not sensor-well defects, but electronic spikes of some kind during readout. The blanket noise is significantly stronger in the ISO 1600 image, showing black dots and tiny globs in areas where the under-exposed ISO 100 images only have mild modulations.

Simply pushing ISO 100 to all the other ISOs with bit-shifting would have given better results than the inept amplification that the camera does. Did anyone even test and compare the two options? Now, I can't say much bad about the camera's ISO 100. It has almost no blackframe read noise to speak of, the noise at most tonal levels seems to be almost totally shot noise (with an apparent well capacity of about 4500 electrons).

It is painful to know that I have a better "ISO 1600" hiding in ISO 100, unreachable with the camera's meager -2 EC. What the hell is wrong with these companies?

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John

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