I’ve owned three cameras with Foveon sensors. Here’s why I think they’re so special, and why they didn’t take off...

I’ve always had an interest in photography, and from an early age I became the designated photographer at family events and holidays, often handed a cheap disposable camera and set loose photographing friends and family. Of course, waiting for the film to come back had a certain magic to it, but predictably this became replaced by a digital compact camera in my teens as they became affordable.

My first ‘proper’ camera, however, was a Sigma SD14 – at the time I thought this was a perfectly normal choice, though looking back on it now I now know it was a rather quirky camera. Sigma carved a name for itself as a manufacturer of reliable and solid third-party options over the years, though in recent times has stepped into a higher gear with more premium optics, seen in its Art and Sports lenses. When it came to cameras however, Sigma has a tendency to be the outlier, and straying far from the norm. This was seen most recently seen with the company’s full-frame mirrorless Sigma BF.

I was a photography student when I bought my Sigma SD14. I had owned a Sigma DP1 compact camera previously, and the lenses available in Sigma mount were at the time cheaper than the same optics for Canon and Nikon – as a student every little helped! Some of my bargain buys included a Sigma 50mm f/1.4 EX DG HSM and 70-300mm f/4-5.6 DG Macro.

Rather naively, at the time I don’t think I fully understood its unique digital sensor technology. Though of course being a camera journalist I now know all about them. Sigma cameras, like my SD14, use a Foveon chip. Modern digital sensors typically use the ‘Bayer’ array filter pattern (though there are exceptions such as Fujifilm’s X-Trans pattern).

With CMOS sensors that use the Bayer array there is a grid of red, green and blue filters placed over individual pixels, with half of this being dedicated to green as the human eye is more sensitive to this colour. The camera also uses a process called demosaicing to interpolate – effectively this is where your camera takes its best guess as to what the missing colours should be.

Foveon sensors are special because they use three layers of stacked photodiodes, each sensitive to its own blue, red or green color channel. One of the greatest injustices with Sigma’s Foveon technology (in my humble opinion) was perhaps a lack of marketing… Foveon cameras were usually billed as having a very high number of megapixels. While this is technically true, with each red, green and blue layer containing its own set of pixels, this usually got mixed up with total image resolution and often came across a bit misleading. My Sigma SD14 for example, had 14MP of color data split over three color layers, but the actual resolution of each of these was 4.7MP so the total resolution for how large you could blow up the image or crop in was limited to quite a meager amount.

I love many of the images I took with my Foveon cameras over the years and the colours always looked particularly vivid. The black and white photos also really popped as the internal IR filter could simply be popped off the camera allowing infrared photos to be taken with ease. However, I think it was a bit too ahead of its time as the processors evidently struggled to handle the vast amounts of data from three colour layers – I remember all too well regularly waiting up to 30 seconds for the memory buffer to clear. It also had no live view or video function, and it really struggled to produce clean images at higher ISO values meaning the CMOS camera I upgraded to after owning my SD14, was a much better all-rounder.

I am, however, more optimistic than ever for the future of Foveon. We now have powerful processors capable of recording vast amounts of data such as Canon’s EOS R5 Mark II with its 45MP RAW files, pre-capture and 8K video and suitably fast CFexpress cards now, too.

I’m still holding out hope for the long-awaited full-frame Foveon from Sigma, and with some clearer marketing that leans more into color quality than a misleading large number of megapixels, would give it every chance of success.

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Take a look at the best DSLR cameras as well as our Sigma BF review. For more info on Sigma's ground-breaking sensor tech be sure to read our article: Will Foveon sensors will ever return?