I have to admit I don't follow this segment of the market very much (my expertise being medium format capture and software). But I love new cameras and new ideas and am a tech-nerd in general so I went ahead and read through several pages of various sourced info/opinions I am left in utter confusion.
Given that we sell camera kits anywhere from $5k-$60k and to a broad range of kinds of customers I'm the first to tell you that price is not always a stumbling block. But I'm finding it very hard to find the unique selling points that would compel any of our customers to spring for this compared to the other options out there.
I make this post honestly in hopes that someone will chime in with some compelling reasons.
Doug Peterson (e-mail Me)
The Foveon sensor have several advantages, but most of them are unfortunately theoretical. The following assumes that the new sensor is similar to the previous Foveon sensors, which is not a given.Advantage 1) increased sensitivity.
The color-filters used in a typical Bayer-design will allow approximately 40% of the light to pass. A Foveon sensor should be able to get a about 1,3 stop advantage.
1a) you only get this advantage if you can match the noise-level in the rest of the system.
1b) the color response can not be chosen as flexibly as a Bayer design.
Tech speak: to convert a RAW-image into a typical color-space (e.g. sRGB or Adobe1998), you usually start by applying a "camera matrix". This will increase the noise by a factor called a "condition number" (gory details here: http://en.wikipedia.org/wiki/Condition_number
). If the color filters have a large overlap, the condition number is large. Typical Bayer-designs have a condition number in the range 1-2. Previous Foveon designs had condition numbers exceeding 10 (rough estimate). Thus, the color-noise is increased by at least 3,5 stops in practice.Advantage 2: improved lens correction
It is significantly easier to fix problems such as lateral chromatic aberration perfectly in software.
2a) the wide color-filters means that the color channels will loose sharpness due to CA. This is similar to a panchromatic BW-image using a lens with a lot of CA.
2b) you need software that will do it.
Sigma could fix 2b... May I suggest cutting a deal with someone who makes an advanced RAW converter ;-)
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The SD1 should be great as a pure BW-camera. All the disadvantages of the Foveon sensor mostly vanish in this case. This does, of course, assume that the software does the right thing and does not add a lot of noise before converting to BW.