Have you ever fallen down the camera research rabbit hole? I have, many times. Only, this time, it was a search without success. Because the camera that I was trying to find information on, the Sigma SD Quattro, is a true oddball. Though there’s a decent Sigma group on Flickr and a few old SD Quattro reviews, there’s little information beyond that and nobody seems to own one. I quickly decided that I needed to see for myself what this strange Sigma’s all about.
First impressions – it’s a weird one. A camera designed with originality. It’s got a weird lens mount, unorthodox ergonomics, and a decidedly un-digital methodology. It’s a camera that forces our habits to change if we want to get the most out of it. But most unique of all, it has a sensor that everyone (even people who hate everything) say is great, so long as you stay within certain parameters.
All About the Sensor
The Sigma SD Quattro is a digital interchangeable lens mirrorless camera first released in the year 2016, with a 29 megapixel sensor that punches above its weight to create images with depth more akin to those of a 40 MP sensor. Is this witchcraft? Actually, it’s Foveon. Never heard of it? That’s okay; most people haven’t. Foveon is a sensor that’s very unique in consumer photography products. They’re rare, and that’s largely because only one company produces these sensors. That company is Sigma.
Now, I consider myself to be a bright guy. I’ve restored cars. I can take things apart and get them back together (mostly). So, I’m going to take a stab at going through what makes this camera’s Foveon image sensor (and by extension the camera itself) such an interesting and unique product.
Here goes everything.
Your average digital camera sensor is of a Bayer design. So, when it captures information, it is actually stripping the colors down at the pixel. Each pixel is designed to only capture one particular color (red, green, or blue) in a sort of mosaic weave pattern. What Foveon sensors do is layer red, green, and blue color-sensitive diodes on top of each other. This means that every single pixel is actually capturing color, unlike the typical Bayer sensor.
What else does this mean? It means that the sensor is recording information on a massive scale. I can see the question forming in your head. “But it’s only 29 MP, and that is not massive.” Well, let me try and explain that one.
Due to the three layers, the top layer of pixels records mostly blue (but red and green as well) and luminance information, and equates to approximately 20 MP. The second layer records mostly red (again, also a little bit of blue and green) and is approximately 5 MP while the third and final layer captures another 5 MP of mostly green (once more, also a little red and blue). Every pixel captures the three main colors, luminance is separated out for noise reasons, noise is reduced, and the images (especially color images) are phenomenal.
The math does not work out, I know. 20 + 5 + 5 =/= 40. But, somehow, images from this camera are up to that level. I checked. My regular digital camera is a D610. That is 24 MP of full frame sensor. It has never been accused of having a bad sensor. In fact, it is pretty damned good. The Quattro has slightly more megapixels but APS-C, so at a disadvantage in terms or detail and depth, right? Let me tell you now, the Nikon gets smoked. When I look at D610 RAW files versus the DNG RAW files of the Sigma for the first time, I laughed. Seriously. Out loud. My daughter ran into the room to see if I was watching something funny. When she saw that I just had a photo on the screen, she left.
According to an interview I read, the benchmark for this APS-C sensor was the Nikon D800E. A full frame 36 MP beast which was possibly the best DSLR of its generation. The Sigma SD Quattro out-resolves it. Easily.
Have you ever taken a photo of black lines on a white piece of paper? Have you noticed that those black lines always look colored? I saw this and had to replicate it. It does exactly that. The way a Bayer sensor works by not absorbing color information leads to that. I replicated this with the Sigma SD Quattro and what did I see? Sharp, clean, black lines on a white piece of paper. No weird color ghosts running up and down the line.
I have no doubt that the image files on the screen were of 40 MP quality. No doubt whatsoever. And you know what else? They were clean. They were sharp. The colors are vibrant without any bleed. I normally like to play with the color wheel when it comes to editing. I started to and realized that it would be an insult to the files. What I went for, in the end, with every photo was to try to create an E-6 film-worthy edit. I tried to edit to make colors as true to life as they can be. And it was not difficult at all, because everything is just there in the raw data.
“Wow! This sounds amazing! Why isn’t every manufacturer using these sensors?” You ask.
Patents? Some other reasons, maybe? I truthfully don’t know.
“Well, why isn’t every photographer using a Sigma SD Quattro?” You ask.
That’s a question more easily answered.
The Body – What?
Let me say this again; what? It’s a mirrorless camera. It’s actually lightweight and looks to be extremely weather proof. Everything has a rubber plug or a latch. It also has an SLR lens mount with an SLR-length flange distance. On a mirrorless? Yup. Let’s take a look at that quirk, first.
The Sigma SD Quattro is a mirrorless camera with an SLR lens mount for the Sigma-made SA mount SLR lenses. Not a big deal, as far as lens availability, since Sigma makes every Sigma ART lens in that mount (I was using the 30/ 1.4 A exclusively). But it is an odd choice for a mirrorless camera. In order to allow mounting of Sigma’s SA lenses, Sigma designers needed to add a shoulder onto the body of the SA Quattro to approximate the mirror box of an SLR camera, and to get the flange distances correct. This is similar to Pentax’s treatment of the mirrorless Pentax K01, which used their SLR K mount. Except Pentax did it more elegantly than Sigma.
In Sigma’s case, the SD Quattro has a big round protuberance on the front of what is actually a very comfortable camera. So that this bulbous bulge is not a complete waste of space, Sigma did throw the on/off switch on top of it. In addition to allowing lenses to mount to the camera, the SA mount also makes it a very front heavy camera. Attach a lens to it and it instantly tips forward. Prime lenses aren’t egregious. An ART series zoom though? Forget about it. This is 100% a two handed camera. One on the grip and one supporting the lens. You have absolutely no choice.
The Sigma SD Quattro has a rangefinder style body. Yeah! Rangefinders are super popular. A good viewfinder in the corner so you can kind of frame with both eyes open. Except you can’t. Not with this camera. The viewfinder screen is on the right part of the body, about three-quarters of the way over. Closer to the grip than where you would normally find an RF viewfinder. This is a bit odd as you are so far removed from the centerline of the lens.
You might be thinking that it’s a mirrorless, so who cares? What you see is what you get. Sorry, but no. The viewfinder’s placement did create some composition issues for me. You naturally line up a shot based upon where the viewfinder is and where the lens is. They are normally close to each other so it works out. Here though, it never did. I always had to move a little if I just walked up and pointed the camera at the subject. I would have to turn it on, look through the viewfinder/screen and frame up while composing. I had to use the camera to compose, not my eye. If I were shooting a grand landscape where everything is f/16 or higher, it would not really matter. But in more open apertures where focus point placement mattered, it was a little more difficult.
And the Sigma SD Quattro has an undeniably odd design. Just look at it. Why is the grip higher than the rest of the body? I do not know. But though it looks odd, it is comfortable to hold and manipulate. I have big hands. The grip fits me very well. It’s sculpted with finger recesses, and very rarely did my pinky slip below the camera.
The dials are easily reached, but everything else is most inconvenient. Focus point selection is through a button on the bottom. Five straight days of using the camera and I still had to look to see where it was. Same thing with the direction pad, and the AF-L (back button focus) button. The shutter release button is okay. It’s a piece of plastic that you push down. There is no real resistance. Basically it’s a laptop key. There’s no half-press feel in it. The button is, however, where you would expect it to be.
Let’s talk about screens. Normally I wouldn’t care much about a camera’s LCD, but this is a mirrorless and they live and die by their screens. The Sigma SD Quattro has a big, fixed, rear screen with a sub screen for basic setting information (hugely useful) and a big viewfinder screen. The problem is that they are pretty awful. I will be the first to admit that I prefer an OVF over a screen pretending to be an OVF. Size does not mean accuracy. If it was not for the histogram being displayed in the finder, all of my shots would have been off. Seriously, it is amazing just how much the image in the OVF differs from reality. It lags, images seem jagged at times, and it’s slow to resolve.
On my last day of using the camera, I took it down to the shore and set it up on a tripod. In order to keep the sky from blowing out, I slid a two stop soft Haida grad filter into place. With my D610, or any other OVF camera, I would watch and stop lock in the position based on what I could see. Two stops is a visual difference. Looking through the viewfinder, and even the rear screen on the Sigma, I could not tell where anything was! The only solution, again, was to watch the histogram and keep sliding the filter down until the highlight side started to slide away from the edges! It seemed to work but should not be that way.
These belly-aches noted, one great aspect of the camera screen set up is the small, black and white sub-screen that allows you to see and quickly change basic settings. It’s like having the top panel LCD screen that many cameras offer, but with the added bonus of being able to change things right there.
A Film Shooter’s Digital Camera
I will admit that a lot of what I’ve written might sound kind of negative. It sounds that way because it is. There are many odd things about this camera. What redeems it then? The fact that shooting the Sigma SD Quattro is like shooting a 250 frame roll of Provia. Yes, that is what you can squeeze out of the camera battery and a 32 GB flash card. Yes, 32 GB for 250 photos. I put a 64 GB card in and was told that I had about 560 shots worth of room. The files, due to the sensor’s method of capturing all color information at every pixel, are approximately 108 MB in size (DNG RAW files). You can save yourself some room by shooting JPEGs. Those are only around 55 MB each…
Let me explain the slide film analogy. The colors are crisp and the camera makes its best shots at ISO 100. Anything higher and things get noisy and ugly. Shooting with this camera was like looking at slide film for the first time after shooting only negative film.
Now, I will readily admit that I am used to seeing 24 MP Nikon files. No one complains about those being terrible. The look of images is massively different from the Sigma and its Foveon sensor. The blacks are deep, the whites are bright, and the colors are amazing. There is clean contrast and sharp lettering everywhere. No need to mess around with sliders or color wheels to find a saturation that best reflects what was there. It’s already there. It’s almost as if you shot a roll of Ektachrome or Provia and then scanned it. Except the scanned film would still require some messing with in order to get the final shot closer to where the Sigma files already are.
Besides the colors and sharpness, what makes this a film shooters digital camera? Pace. You absolutely cannot rush this thing. Start up time is sluggish. Composing is not quick due to the situation I described above with the screens. You are limited to basically ISO 100. Every shot takes some time to process and save to the card. It’s a camera that rewards set up and deliberation. It is digital, of course, but it’s also somewhat anti digital. It’s not a snapshots camera. The published burst mode frame rate is high but due to the slow-to-focus nature of it, it is basically a single shot at a time camera. You need to think before you shoot. Because of these limitations, you look for things that you would not ordinarily look for. I found myself looking for textures and shadows. For colors and contrast. I became incredibly interested in moss for some reason. Vibrant greens and browns. Contrast and texture. Moss! Never in my life did I feel like that was worthy of a shot.
Were there issues? Absolutely.
Problems, there were a few. Wait. Let me rephrase that. There were not a few. That implies more than I mean. In reality, there was really only one or two things that I would classify as a problem. The rest were mere inconveniences that are no big deal, as long as you shift the way you use a digital camera. The actual, real and tangible problems were overheating and metering.
The camera overheats. Granted, it has been 95 degrees with 85% humidity, resulting in what feels like temps of 105 degrees, but I’ve never used a camera where shooting stills has brought on a heat warning. The Sigma SD Quattro, however, changed all that. And turning it off really didn’t help. It never froze completely, and the moment I got the warning I took the shot, turned it off, and placed the camera in my bag. The next time I brought it out for use, I got a couple of shots before encountering another heat warning. Apparently this is common, but it’s also not something I want to mess with. Putting the camera in front of an air conditioning vent helped a lot.
The second problem was the metering. Again, just like with the screens, pay attention to the histogram. This is something that I am not accustomed to. I absolutely never pay any attention to the histogram. With this camera though, it is a necessity. The screens do not give you an accurate picture of what you are shooting. They are there merely as an approximation. For me, I needed to be 2/3rds to 1 stop under-exposed to get the photo that I was looking to capture. If I went with the meter, the skies would have been blown out and unrecoverable. The files are so large and flexible that I could recover shadows while having my brights still be there.
Now for the inconveniences. Slow start up and a weird shutter lag. Turn it on and wait. Frame a photo and then press the shutter to take the photo. Problem is that the auditory response to pressing the shutter is delayed, so the first couple of days of using this camera, I had this feeling like all of my photos were going to be blurry. They weren’t, as my shutter speeds were properly high to avoid shake, but pressing the button and then moving on created a split second panic of ruined photo due to the delay. I’m not sure if this delay is due to the processor, or the massive file sizes, but there is a delay in the taking and then writing to the card. Which brings me to another minor inconvenience. The file sizes. They are large and you will need a large card. And a decent computer to handle it. The moment I loaded my files into Capture One, the fans kicked on and basically stayed on the entire time.
There are a couple of other things that bothered me, but they are nitpicky. The battery life is not amazing (about 250 shots) and the BULB mode seems to actually be timed to about 40 seconds. The camera is a deliberate shooters camera. Not a walk around snap shots, whatever catches your eye kind of thing. This doesn’t mean you can’t use it that way. I did. It just means that you need to really think about what you’re doing in order to get the most out of it.
Odds and Ends
I didn’t try shooting moving objects, as that’s not necessarily what the camera is meant for, but I did try to put the Sigma SD Quattro through its paces. I shot landscapes, people, street photography. I was out in the early blue to golden hours and in the height of the afternoon heat and sun, and here are some rapid-fire final thoughts.
The focus is slow, but that’s okay. You want to get your shot in as few attempts as possible. I thought of it as a film camera loaded with a $12+ roll of slide film (i.e. not to be wasted). The best ISO is the base ISO, so set it to 100 and leave it there. This sometimes means that you need a tripod. You’re going to start looking for different things. As I mentioned earlier, I was looking for colors and textures, not things that I would normally choose as my primary subject. I was using filters far more often than usual to protect highlights (much like you would with slide film). The body is oddly shaped, but it handles incredibly well with the lens being the perfect place to position a hand while you hold the grip with the other. The 30mm f/1.4 ART lens is, well, amazing. Even down to 1.4 it is sharp.
Who is it for? Should you buy one?
Who is this camera for? I’m honestly not too sure. It’s not convenient, but it does reward. Would I keep it? Yes, I would. I have general-use digital cameras and lenses. And a digital point and shoot. What this camera offers is something that those cannot. A different way of looking at the world. It rewards a slower, more deliberate pace. It rewards thought. My only regret is that I was not able to road trip out to some deserted town to photograph derelict buildings and maybe some grand vistas.
As a purchase today, the Sigma SD Quattro is very reasonable. You can get the body and that excellent lens for $699 brand new, which is a pretty good deal. Even better buying second-hand, where gently used units can be found on eBay for under $450.
I realize that the “different way of looking at the world” line sounds cliché and something that all camera manufacturers would love for you to believe. The fact is, however, that this camera absolutely does do that. Its limitations are also its strengths. You cannot just simply jack the ISO up to match available light, rely upon enormous dynamic range, or use IBIS (it has none) as a crutch. You cannot bend it to your will. You have to work with it. And after working with one for some time, and in no small part because of the impressive color depth an incredible clarity of the images it makes, I really like the Sigma SD Quattro.
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