Sigma bends to the will of their customer base.

I'd say it's more like they're bending to some good ol' fashioned market pressure. And that market pressure has a name: Nikon D800, for $3,000.

Does Sigma make their own cameras? Or do they sub it out?

And how do they get away advertising this as a 46MP camera when it's resolution is 4800x3200? That looks like 14.4 to me.

And how do they get away advertising this as a 46MP

The Foveon sensor they use does not have the standard RGBG Bayer filter but each pixel has separate RGB photosites stacked vertically. This does give it higher color resolution than a standard Bayer sensor, but not 46MP worth. I've heard the advantage is closer to 20-30% over Bayer.

I understand that they have a separate sensor layer for each channel.

I still don't see a practical difference when I am working on a photo in PhotoShop.

A higher color resolution? Take the blue pixel, for example. In PS it can only be 256 different shades of blue, on the blue channel, right? How would you take advantage of this higher resolution in PS?

It's still only a 4800x3200 image, right?

Unless there is some practical reason for it, it would be like a 12MP camera that shoots RAW and Jpg at the same time and adding them up to say they have a 24MP camera.

It's a higher "color" resolution because each pixel has it's own definition, versus interpolating the information from the surrounding pixels as a bayer does. That said, the Foveon chip should lead to more detail for each pixel during capture, so your level of 256 should be more accurate and relevant to that one pixel than on a Bayer layout.

The 46MP is marketing BS, it is 3x15.3MP (I think) to get there. Really, it's a 15MP camera.

I don't know. I am not in the same world. buting things only under $10.00
But years ago Sigma made YS lenses and later denied it
and made other lenses that were not -well they were- YS
with the adapter held with setscrews- and denies it
and more recently made a camera that was almost a pentax k
why make a unique lens mount and create and Instant orphan.
I think they make good equipment but have strange management.
I Not to be taken too seriously.

Imagine a Bayer filter and Foveon sensor the same size and both produce files of 4000x3000 pixels. Normally people shoot black and white test charts to see how many line pairs per mm can be resolved. If you shot a test chart that had lines of color instead the Foveon sensor would resolve more than the Bayer. Why? In a Bayer filter each pixel really only has the true value for just one color. The demosaic algorithm in the camera or RAW converter looks at adjacent pixels and makes up the other 2 colors. Eventually the lines would get so close that different lines would be over different pixels and the demosaic algorithm could not determine the correct color. These links may help.

http://en.wikipedia.org/wiki/Bayer_filter

http://en.wikipedia.org/wiki/Demosaicing

Richard, they "get away" with it, because their camera performs. It also captures more red and more blue pixels than any 46 megapixel standard digital camera could. In fact, very few medium format cameras capture so many red and blue pixels as the Sigma SD1 does. That gives cameras with Foveon sensors a distinct advantage in certain situations. As it is with standard cameras, that capture a total of whatever their megapixel counts state, the Foveon sensor cameras capture the same. What is funny is that many people said the same thing about the Sigma SD14 (which I own), and the fact that the camera actually shoots 14 megapixel JPEG images just didn't seem to ever enter the conversations these people had. It's as if they just ignored the fact that the camera produced 14 megapixel images. Weird.

The fact is though, the "interpolated" higher resolution image does not retain/contain the same level of detail as the "un-interpolated" images the camera produces. Interpolation introduces blur, which we often call "Bayer blur" when we are talking about "normal" digital cameras (as opposed to Foveon sensor cameras).

Take a look at my comparison gallery: http://ffphotos.zenfolio.com/SigmaSD14

I don't know, Scott - the images on your gallery have detail, but do they really have that much more detail than ones from regular digital cameras? If I were shopping, and comparing a D800 or D800E to an SD1, for the same money, the SD1 might be able to resolve the same amount of detail from the sensor, but I'd also have to consider the lens selection. B&H lists 256 lenses available new in Nikon mount (and there a huge used lens selection), 42 in Sigma and they're all Sigma made lenses. Keh lists 5 lenses available used for Sigma and they're all zooms. In Nikon they have 384 AF lenses and 392 MF. (A lot of those are overlaps - minor variations getting separate listings - but still, it's a very large difference.)

Then there are the intangible benefits of the D800 being FX frame over the SD1's DX frame - larger finder, 50mm lens acts like a 50mm lens, larger finder, the lenses don't have to resolve as many lp/mm to get the same real output, larger finder, etc.

Maybe the SD1 has a certain something that appeals to your photography, but at the same price is it really competitive with a D800 in the market? At nearly triple the price, is it really competitive with a D7000?