Digital Panatomic-X: The Sigma SD Quattro Foveon

The Utterly Weird, but Compellingly Fascinating Sigma SD Quattro

I’ve always been a lover of quirky, neglected and/or unfairly maligned cameras. Hence, my allegiance to the Leica M5 and the Ricoh GXR, two of my favorite cameras, both of which were critical and popular disappointments. I also own, and love, the Sigma SD Quattro. Sigma says its 20MP APS-C sensor produces a resolution “equivalent” to 39MP. In reality, it’s way better than that. My experience is, when shot at ISO100, it easily resolves fine details much better than the 36MP D800E, which was, at the time of the Quattro’s introduction, the Mack Daddy of high resolution full-frame DSLRs, and I suspect it can hold its own against the current crop of 60MP mirrorless. All of this out of a 20MP APS-C sensor.

The SD Quattro’s Foveon* sensor is what makes the SD Quattro unique and allows it to punch so high above its weight. Traditional high resolution digital sensors employ a Bayer filter sensor where red, green and blue photosensors are positioned at discrete locations. The Bayer filter then ‘interpolates’ them (i.e. makes an educated guess about what, for example, red would look like in a position where there is no red photosensor) to produce a full color image. The Foveon sensor ‘stacks’ the red, green and blue photosensors on top of each other at the same location ( in other words, there’s a red, green and blue pixel at every position) producing significantly sharper files than a Bayer filter sensor at same resolution. Frankly, it’s not even close. ‘Why’ it would do so, from a technical standpoint, is beyond my expertise. Just know that it does. If sharp resolution files are your thing, a Foveon sensor is what you want.

It also produces really nice, tonally rich B&W files that remind me of the look of Panatomic-X, and does so right out of the camera with exceptional jpeg files. While I’m hesitant to admit it, given my love of the M9 CCD Monchrom’s output, I think the Quattro is the better B&W camera. It’s that good.


ISO 200 B&W Conversion in Silver Efex

Build quality is excellent. This is no cheap, plastic-y camera. Made from a magnesium alloy, fit and finish is really nice. Buttons and dials feel robust. Ergonomics are surprisingly intuitive, much more so than digital Leica’s and contemporary DSLR’s and mirrorless offered by Canon/Nikon et al.

In spite of all the above, the Sigma SD Quattro (and the Quattro H) are most decidedly not for everyone. They aren’t a camera you’re going to grab going out the door if you’ve got other less complicated options. They’re cumbersome in any situation in involving live action – people photography, ‘street photography’ , sports. They’re bulky and super slow in operation. If you’re shooting RAW, don’t even think about shooting them at any ISO above 400; in fact, it’s advisable to not shoot at anything other than its native sensor sensitivity of 100 ISO… or 200 ISO in a pinch. (Shooting jpegs is another story, which I’ll address shortly).

But man, when you use it as it was meant to be used – 100 ISO steadily handheld in sunlight, or on a tripod – the results are remarkable. It gives you DNG files that allow almost endless manipulation to get whatever look you’re after. They are particularly good for B&W conversions. They are incredibly sharp even at large magnifications, and their Foveon-ish* sensor produces a noticeable something that even current 60MP sensors don’t. Viewing the output of my M9 Monochrom (itself capable of really sharp, clean fines at lower ISO way better than you’d expect from an 18MP sensor) with an out-of-camera JPEG from the Quattro makes it clear just how good 1) Quattro jpegs are and 2) the Foveon sensor is in B&W.

Out of Camera jpeg from the Quattro using the 4:5 Aspect Ratio In Camera Crop

A DNG RAW file from the M9 Monochrom – Processed in Lightroom

The ability to shoot DNG RAW files is a major upgrade from Sigma’s previous Foveon cameras, which shot a proprietary RAW version that required conversion in clunky, bug-ridden Sigma software (although the latest version Sigma Photo 6.8 is pretty good). In 2004 Adobe created the DNG file format to replace the various proprietary Raw (.RAW) formats of differing digital cameras. The goal was to provide a standardized file format that could be processed on any computer system or viewer without special proprietary software. DNG files are supported in software such as Adobe Lightroom, Photoshop, Camera Raw.

With the Quattro, you also have the ability to avoid shooting RAW format entirely: the jpeg processing engine is really good, which allows you some ability to shoot at higher ISO’s – expose properly and you can shoot jpegs in color up to ISO 400, and black and white to ISO 800. Yes there is some degradation as you increase ISO, but because of the clarity of the Foveon pixels you can still print and display at very large sizes. One upside of shooting jpeg is the reduced file size; the DNG files out of the Quattro are enormous and take a lot of processing power to work with. Of course, the downside is you’re stuck with the rendering the jpeg engine gives you. Suffice it to say that the Quattro is the only camera I feel comfortable shooting in jpeg mode.

Out of Camera jpeg From the SD Quattro – Me Looking Like Uncle Festor


And then there’s the issue of lens choice. The Quattro employs the Sigma SA mount, a mount Sigma used for all its SLR and mirrorless cameras until they discontinued it in 2018. As such, you’re limited to pre-2018 Sigma optics (of which there are plenty and most of which are really good, the trade off being most are also quite large). I’m currently using the Sigma DC 17-50 2.8 EX HSM which is solidly built and sharp at all apertures. If you need a ‘standard’ prime, the excellent Sigma 30mm 1.4 ART lens fits the bill nicely (that’s it on the photo that leads off the piece). Just realize that you’re going to be limited to already existing Sigma optics.

Sigma discontinued the camera in 2018. They’ve replaced it with the fp, which uses a full-frame Bayer sensor. This means that the Quattro is probably going to be the last in the line of commercially produced Foveon-sensored cameras, as Sigma wholly owns the Foveon patent. I applaud Sigma for doing something different; their Foveon cameras, from the original 4MP DP series through the Merrills and ending with the Quattro are all fascinating departures from the norm. IMO, their strengths – super sharp, super detailed RAW files – transcend their obvious limitations. It’s a shame the marketplace killed it. I suspect Foveons, and the Quattro in particular, are eventually going to achieve cult status, with in-the-box examples bringing exorbitant prices. Ten years maybe?

UPDATE: Maybe not…..

July 2022: Sigma CEO Says More Foveons Coming. Yay!

Should you buy one? Yes. Full Stop. These things are currently bargains used. Buy one – or an equally weird Merrill or DP Quattro – and use it. The question is which one. I’ve owned most iterations – the 4MP DP2x, the DP2 Merrill and the Quattro. I loved the pocket-sized ‘4MP’ DP2x with its fixed 24mm 2.8 that produced beautiful color files looking like those from a camera with 5 times its resolution but, alas, the lower pixel count precluded you from printing big. The Merrill’s produce stunning output, but unfortunately tether you to Sigma’s RAW processor, which is a nightmare to work with. Were I to choose one my preference would be the Quattro, as it offers the ability to shoot DNG files you can post-process in Photoshop or Lightroom without recourse to the dedicated Sigma software and it allows use of the entire range of Sigma SA optics. It also shoots really good jpegs, which the Merrill did not. I haven’t used the DP Quattro series, which Sigma offered after the Merrill and before the SD, but I assume the image quality is on par with the SD. As I understand it, the DP series is the SD with fixed lenses (and a very weird design).

The Quattro H, a slightly larger sensor than the Quattro (1.3 crop as opposed to the 1.5 crop of the base Quattro) commands a premium over the APS-C base Quattro, but I don’t see much functional distinction between the two. Given the price difference, I’d stick with the base APS-C model. Current prices are all over the map, as you can see from the Ebay offerings below. Having watched past auctions, $800 should get you a lightly used Quattro body and either the 30mm 1.4 Art lens, or my choice, the 17-50DC EX with IS. What you’ll get is an APS-C camera that easily out-resolves the latest Leica M, isn’t going to ever become “obsolete,” and will keep your interest permanently. Certainly, if you aspire to landscape photography, take things slow and use a tripod, this is the camera for you. Plus, this thing just oozes cache; pull it out and start pointing it around and every DSLR toting Ansel Adams and Leica M HCB wannabe is going to be secretly envious. Thorsten [von] Overgaard will be completely flummoxed. Try doing that for $800 in Leica land.


Get the PG-41 Power Grip and Extra Batteries. You’re Going to Need Them.

We talk of Leica being the one camera company offering digital cameras that hearken back to – and retain vestigial features of – film era cameras and their operation. I’d suggest that the Sigma SD Quattro does the same. Operation is reminiscent of a MF film camera loaded with a high resolution low ISO film. Think of a Hasselblad loaded with Panatomic-X.

The Quattro requires you to slow down and think about what you’re doing. Its slow start up and interminable write times give you no choice. Its energy hungry sensor eats batteries, so, much like film, you’re best to make every shot count. There’s no doing it wrong and having the camera’s automation correct you. But do it right and work around the camera’s inherent limitations and the results can be stunning. It rewards pre-visualization and proper technique with subtle color detail or wonderfully detailed, tonally rich B&W files. Those who’ve worked with MF film cameras will feel right at home.

Mine. Yes it’s Big. So is a Hasselblad 501CM with 80mm Planar.

*The X3 Quattro sensor used in the SQ Quattro is slightly different than the original Foveon sensor. The blue photosensor layer at top has 4 times the high resolution of the red and green  photosensor layers underneath it are of lower (1/4th) resolution.

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13 thoughts on “Digital Panatomic-X: The Sigma SD Quattro Foveon

  1. Leicaphila Post author

    One thing I can always count on: post an article about Sigma Foveon cameras and the resulting reader silence will be deafening.

    1. Brian Sweeney

      When I saw the title, thought it would be about the original Leica M Monochrom. From the first picture from that camera, figured I was shooting with Panatomic-x again. I shot with it almost exclusively in the late 1970s on a Nikon F2a and Nikon F Photomic “Bullseye”.
      I’ve had the M Monochrom for 10 years now, use it all the time. First thing I do after transferring the images to the computer is to run them through my Fortran-77 Program to add a Gamma curve to the DNG file and to correct the “Black Level” set by Leica, and that I do not like. The program also restores one underpeforming column that it picked up. Restore, not map out and average over. I’ve been using Digital Imagers for over 40 years now, paid to work on them in the research lab.
      The Foveon sensor: Knew about it when it was still in the R&D stage, a friend explained how it worked on the whiteboard in the optics lab after reading an article. Sad that Sigma is just using a color mosaic filer on the latest cameras like “everybody else.”

      If I see a good price on a Foveon ILC camera, and the Sigma Quattro being closed out- might get one. I only have two questions.

      Is the File Format documented well enough that I can read it in using Fortran?
      Does the Raw format use Big-Endian or Little Endian? I prefer little endian. The M240 used Big Endian. Skipped it, Big Endian is a PITA.

      Gamma Curve for M Monochrom, also the column-restoration algorithm:

  2. Dan Newell

    You must be seeing something on the print that isn’t being portrayed by a backlit computer image.

    1. Leicaphila Post author

      I certainly see it on the magnified jpegs shown. The Foveon photo is sharper and has a 3D effect that the Monochrom doesn’t. Click on both photos to enlarge them. Take a good look. If you don’t see it I’m not sure what to tell you, Dan. Maybe it’s all the painkillers I’m on.

  3. Dan Newell

    I didn’t enlarge them so I see where you’re going with it. Impressive jpeg for the camera that it is.

    I haven’t shot with the M9 so I’m not sure what’s left on the RAW to pull.

  4. Steve K

    Alright Tim, you know we’re all here, so I’ll stick my head above the parapet.
    Here’s my short take on the Sigma cameras: the shortcomings outweigh the benefits. So, whatever miracles they may be capable of, I won’t be following you down this path. Yes, that is probably a shame, as it might have been fun to try.
    I think you already know this but I’ll say it anyway. You’ve earned the trust of your readers, so we want (at least I want) to see these cameras as you do. My reaction has been the same each time you’ve written about the Foveon sensor. First I realize I don’t know enough about this unique, possibly game-changing technology. I start poking around the Sigma website to learn more. I might even check reviews on certain unnamed photography sites. Then I catch myself. What am I doing? The last thing I need is another camera, especially one that might be on an evolutionary dead end.
    I hope you don’t mind me adding that I find a slight contradiction in your opinions about Sigma/Foveon, given that you have generally not been a pixel-chaser. After all, shouldn’t aesthetics trump technical wizardry? Let me ask you this: how many pictures in Car Sick would have been improved had they been taken with a Sigma? More to the point, how many would have even been possible?
    So I give my head a shake and remind myself I should try to take better pictures with the cameras I already have. But I do give you full credit for your excellent assessments of these cameras. Anyone thinking of buying one needs to read your posts. And of course I’ll read them too, despite my foregone conclusion.
    Thanks for doing this. All of it.

    1. Leicaphila Post author

      Steve: You are completely right. I’m a total hypocrite for hyping the sharpness of the Foveon while simultaneously denigrating people who consider sharpness the sole criterion of a successful picture. Guilty as charged. But…
      1) It’s fun being inconsistent, consistency being “the hobgoblin of small minds,”and 2) I don’t think I’m completely inconsistent. Let me explain. Yes, Car Sick would not be served by Foveon. Not one bit. That subject is for a Leica or some other handheld quick and easy camera. I also think that type of subject benefits from grain, fuzziness, lack of sharpness. It’s part of the ambiance of the subject. Now, I’m not advocating you sell your M’s and buy a Sigma. That would be really stupid. What I am saying is that, if sharpness is your thing, go no further than the Sigma. It is the Mack Daddy of sharpness.

      Now, are there times when I DO want a sharp camera. Yes, sometimes, but not often. For example, my wife and I were travelling through the Scottish Highlands a few years ago and I would have killed to have the Sigma with me. The low cloudy, half drizzly weather combined with the stark beauty of the landscape would have made a killer series of photos. I did get a few decent shots with my 10MP Ricoh, but man, I’d love to have a 4 x6 foot poster sixed print of that same photo take with the Sigma. That would be awesome.

      There’s a picture on the blog somewhere of my wife standing in front of the ocean with my two dogs. I took it with the Sigma. It is stunning when printed large. Stunning. It wouldn’t have the same impression had I taken it with my 18MP Monochrom. It just wouldn’t.

      So, there’s room for sharpness in various situations. They don’t come around often, certainly not with the type of photography I prefer. But they do exist…and the Sigma is the camera you want when you do encounter them.

  5. Rob Campbell

    I received a copy of Car Sick today, courtesy of a kind fellow Leicaphilia reader who took it upon himself to ensure that I got one.

    I had my first gaze at it a few minutes ago: I’m reeling in shock. My hope is that it is not still representational of rural American life today. I used to think that Glasgow was bleak, full of doom and with little to brighten the soul. And yeah, I guess that it was when I left four decades ago. But it’s bleakness was that of a city that had largely lost its raison d’etre with the demise of heavy engineering. Your photographs force a confrontation with a bleakness quite different: a bleakness that comes from what appears to me to be the absolute loss of faith of a part of a nation that’s discovered it was all a lie, right from the beginning, that the dream, the promised payoff for belief – I don’t mean the religious kind – had never happened. At least, for what it was worth, Glasgow did enjoy its industrial period and produced a massive amount of wealth. The places you observed look as if they had never experienced that phase, had simply died in the womb. The party where nobody came.

    Okay, you have used a very hard, abrasive photographic style which certainly helps along the sensation of harsh defeat, and I guess nowhere actually has an atmosphere that resembles any of the pictures; however, the basic clay is there in the images, regardless of accentuation, technique and the speed of the wheel..

    I guess that it might boil down to rural decay perhaps being more surprising than the city kind, where there have always been the so-called dumps. The expectation is perhaps for the rural always to be the nice girl, unlike the ubiquitous city tramp.

    Whichever way you look at it, that’s some book! Nobody can delve and remain neutral. Eggleston, eat your fucking heart out.

    1. Leicaphila Post author

      That’s a nice review Rob. Thanks. Believe it or not, I think the book is more representative of what’s going on here in “flyover” America than you might think. I live in a thriving liberal, urban community. Incredible growth, opportunity, the streets full of life, cultural stuff abounding. But ride 15 miles due east and you are in rural NC, Trump country, and there is literally nothing but fast-food restaurants, Dollar Stores, bible-thumper churches and hollowed out, dead town centers, and the people who live there are prey to every stupidity. This is what hyper-capitalism, radical individualism and fundy religion has given us. I have no real hope for the future of this country. IMO, we should burn it all down and start over.

      1. Dan Newell

        “The future ain’t what it used to be”- Yogi Berra

        I don’t think burning is necessary, they seem to be plowing and building into oblivion.
        I’ve gone down to Collinsville CA over a couple of years to shoot landscapes. It’s on the California Delta, just northeast of San Francisco.
        While it’s been developed into a wind farm they’ve also plowed every foot of ground to support meat production. Thousands of acres. There isn’t a law on the books for murdering the landscape but there should be.
        I usually just shoot for myself and the kids, if they want a print I’ll make it but they didn’t want any of these.
        Which is understandable, they got on the bus to Freak City a while ago…..

  6. patrick j clarke

    I’ve been an unashamed BW Foveon fan since my first DP1 many years ago, but I’m a self-admitted contrarian as well. My love of Foveon peaked with the DP1 and DP2 Merrill, but when Sigma lent me an dp2 Quattro I just couldn’t deal with the odd ergos of that camera, and I still thought my Merrill produced more “foveon-y” monochromes. It was until earlier this year that I got an sd Quattro and 30mm lens and man, and I was shocked at how well built and robust it was. The buttons are a little mushy compared to my Merrill’s and the wheels on the Merrill are placed better, but I had no complaints with the quality of the build.

    But then I got the 18-35 and the 24mm Art (FF) and it was apparent that this thing gets HUGE quickly. I had been shooting exclusively with my M240 for a year, so it was just shocking how big the sd was. I could work around the slowness, but when I was out shooting “street” it wasn’t as ghost-like as my Leica M was.

    I shot stuff around the property here and some portraits and it worked really well, even if the files are a bit “grainy” compared to my Merrills…but spot on ALL foveon’s BW files are amazing…you may struggle with the camera, the ISO, and even Sigma Photo Pro, but you really don’t have to futz with the files much to get stunning monochromes, and yes I think they are better than CCD Monochrom or CMOS Monochrom overall. But that size for what I wanted to do just was the deal-breaker, so I traded it out. I still shoot and love the DP1 Merrill..and think the DPM’s button and wheel placement, and QS menu are just perfect for how I like to shoot with it in the street. I don’t think I will ever not have a Foveon around, but just not the sd Quattro.

    I really really wish Sigma would team up with Leica and make a super basic M with the upcoming FF sensor…hell, I’d take Quattro H sensor in an M body. A rangefinder makes a ton of sense to me for a Foveon, and I can only imagine how Leica glass would render on a Foveon sensor. Oh, and I’d call it the Leica MF

    1. Leicaphila Post author

      I agree with you about the B&W files from the Foveon.

      I’m not sure about a Foveon sensor in a small rangefinder body. You’d have to shoot JPGs to get 400 ISO, which severely limits the camera for candid available light photography i.e. “street” photography.

  7. Scott Kennelly

    Why would you have to shoot jpegs? I’ve seen quite good images made from Quattro raw files shot at ISO 1600. SPP has improved a lot over the years, and well exposed high-ISO shots can look just fine . . . especially in monochrome.

    I’ve had three cameras with Foveon sensors, though at the moment I shoot with a Nikon D810 exclusively, and plan to buy a 60 MP Sony. I do plan to buy Sigma’s upcoming full-frame camera, with what Sigma has dubbed their “three layer sensor” in it. (Sigma shut down Foveon a while back, and moved all sensor development to Japan, deciding to not continue with the Foveon name, unfortunately.)

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