Interesting, D600 raw comparison with OMD.....

Started Oct 5, 2012 | Discussions thread
bobn2
bobn2 Forum Pro • Posts: 69,787
Re: Interesting, D600 raw comparison with OMD.....
1

Anders W wrote:

Hmm. What is your basis for saying that the E-M5 is actually as good "area for area" as the latest Nikons? If the per-pixel DR would actually be independent of pixel size, as might be expected under equally good technology, we would expect the D800 to have roughly two times, the D600 roughly three times, and the D4 roughly four times higher read noise (in electrons per pixel) than the E-M5. In reality, the Nikons all do significantly better than that at all ISOs, and particularly so at lower ISOs for the D600/D800 and at higher ISOs for the D4. Similarly, the two-year-old APS-C sensor used in the D7000 (and some other cameras) does significantly better than expected in these terms when compared to the E-M5 at lower ISOs and about as well at higher.

Well, maybe I was being a little bit kind to the E-M5 in the hope of avoiding too many brickbats from the faithful. It matches them in QE, it's read noise does not scale area for area as it should. On the other hand for like proportions of the image, it has less read noise than any FF sensor.

Thanks. I have seen you make similar comments in earlier threads and have, on that basis, come to appreciate the importance not only of sensor design but also sensor production facilities. One further question here: Are these production lines entirely different for larger as opposed to smaller sensors or are they somewhat flexible in this regard. If they are inflexible, much of the potential FF advantage would seem to depend on how big a market share FF can actually secure now that it has finally become affordable for the average "enthusiast". The smaller the production, the higher the likelihood that the production lines will continue to do service even though the product has passed its best-before date. Would you tend to agree or am I thinking along the wrong lines here?

A line is really characterised by the minimum feature size that can be fabricated. Canon for instance has two lines, 350 and 180 nm minimum feature size - Sony 5 lines going down to 90 nm minimum feature size, plus foundry service. One can make a 350 nm design on a 180nm line but not vice versa. Once a design is committed to a line, its details will likely be optimised for that line. If like Canon you have a 350nm line, it is virtually useless for small pixel sensors, so to get any investment back you need to schedule large pixel sensors on that. By the same token, if you have to make all your small pixel sensors on one line, making FF sensors on that line wipes out a whole volume of small pixel sensors - so Canon is almost bound to make its FF sensors on its old 350nm line. Sony with 5 lines has more flexibility, but will still tend to make the FF sensors on its oldest, coarsest geometry lines. The reverse of that is that if the old lines aren't useable for anything other than FF, it's in the sensor manufacturers interest to make as many FF sensors as use the capacity of that line - hence I think the low end FF we are seeing. The other option is low end APS-C like the Canon 1100D, but Nikon has more or less shot that fox with the D3200 - presumably made at a foundry and hence outside Sony's own production economy.

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Bob

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