Sigma dp2 Quattro - Foveon strikes again! - manzur fahim

Sigma dp2 Quattro - Foveon at its best!

3rd December, 2014

When Sigma announced the new dp Quattro cameras with the new Foveon X3 Quattro sensor, I was overly excited. I am a proud owner of DP1 Merrill camera and I love the images the camera can produce. So when dp2 Quattro became available, I requested Sigma UK if they can arrange a short term loan for me and some very kind people at Sigma UK approved my request.

I am an avid travel photographer and photography is my passion. The camera arrived just before my Lake District trip, and I thought it would be the perfect way for me to test the camera and see what it can do. I have had the camera for a couple of weeks, and I want to share my experience with others who are interested and looking for some real life experiences, rather than a brick test scene and graph of number of lines a camera can resolve.

A little about the camera and its sensor:

New, exciting and non-traditional technologies have always intrigued me, and Foveon sensor is not an exception. dp2 Quattro has the new Foveon X3 Quattro sensor as its core, a 29 Megapixel APS-C multi-layer sensor. Just like DP Merrill cameras, DP Quattro will also have dp1, dp2 and dp3 models, and will be equipped with 19mm, 30mm and 50mm lens. Their 35mm equivalent focal range will be 28mm, 45mm & 75mm. Foveon sensor works differently to other traditional sensors, as the images below explains:

So a traditional Foveon sensor has a layer for each of the RGB channels, and therefore holds 3 times more color data than a standard sensor. Quattro sensor further improved the specification by adding a 19.5MP top layer, which records blue channel and luminance information. The other two layer records red and green channels and are 4.9MP each. This design change improves the camera performance and also increases noise performance, specially in the red and green channel. Calculating the color information that the sensor can record is equivalent to a 39MP Bayer sensor in terms of resolution.

Design aspects:

Sigma DP2 Quattro and DP1 Merrill for comparison. Quattro is by no means pocketable, and very wide at about 161mm.

Being an owner of a Sigma DP1 Merrill, I can see some definite changes and improvements on the design. dp2 Quattro looks very futuristic and funky, and by no means a pocket camera. Personally, I like the camera design. It is not pocket able, and takes up a lot of space in the bag due to its design but it is exceptionally well built and looks like its from future. The body is metal and the camera is quite wide. The grip is backward and feels very solid when holding. It also holds a bigger battery than the Merrill cameras and battery life as a result is also better.

Sigma Merrill cameras had a more compact design but was not very comfortable to hold. On Quattro, the memory card slot is not anymore with the battery compartment, but on the left side of the camera. This is one of the design change everyone wanted, but I do not like it, because the memory card compartment is now covered by a rubber flap. It has a snug fit and works but I was afraid it might get loose over time. It is also a little frustrating at times when you have to fiddle around with it to take the memory card out and use your nail to try and open the rubber flap, as it does not open that easy. The screen is very detailed with 920K pixels and worked well for me in bright daylight. It lets you see the photos in good detail, unlike the 460K screen of Merrill cameras.

Unique design of dp2 Quattro


If the dp2 Quattro camera is made for one thing and one thing only: it is the image quality. It produces exceptional image quality, and the details and sharpness of the camera is nothing sort of amazing. AF is quite accurate and fast. It is definitely faster than Merrill cameras but slow compared to most other compact cameras. Focus speed is not a great deal for me, and I was ok with the focus speed of the Quattro. AF does hunts at low light and sometimes fails to acquire focus. ISO quality is good but not great. ISO 100 and 200 is pretty much great with a very slight appearance of noise, at ISO 400 it starts getting noise and starts losing color characteristics and detail from ISO 800 and onwards. It is still better than Merrill cameras where ISO 400 starts banding. Low light performance is not that good and visible color rasterization problems occurs at low light. But it is a photographer's tool, when everything is perfect and the light is on your side, this camera can produce photos that can outperform sometimes even a full-frame camera.

The lens is very very good and tack sharp, capable of resolving very high detail. I do not know if it is as good as a Sigma 35mm f1.4 Art lens and such, but it is a very good lens and designed specifically to work with Quattro Foveon sensors. It is a 30mm f/2.8 lens, which gives an 35mm equivalent focal range of 45mm. f/2.8 is quite helpful at low light and the lens is very sharp even at f/2.8. It also produces nice depth of field, thanks to the lens design and 9 blade diaphragm blades.

The overall performance and responsiveness of the Quattro camera is improved considerably from previous generation Merrill cameras. It is now more responsive to user interactions, and the file read/write operation also takes less time than Merrill cameras, but it is still slower than most other cameras. This is not a surprise, as the sheer amount of information readout of the Foveon sensor produces quite large raw files (about 54MB - 60MB).

It can capture about 3.5 frames in burst mode with a buffer capacity of 7 raw files. Based on my file write performance test, Once the buffer is full with RAW files, the time the camera took with different memory card to clear buffer:

* SanDisk Ultra 16GB 30MB/Sec SDHC - 40 seconds

* SanDisk Extreme 128GB 45MB/Sec SDXC - 30 seconds

* SanDisk Extreme Pro 64GB 95MB/Sec SDXC - 29 seconds

* PNY Ultimate 256GB 90MB/Sec SDXC - 30 seconds

So the buffer to memory controller is fast enough for a 45MB/Sec memory card, but anything faster does not really make a difference here. Its good to see that it supports 256GB SDXC cards. For example, DP1 Merrill and Fuji X-T1 did not recognize the card when I tried.

Image Quality:

As I said before, the only reason I like this camera is because of its exceptional image quality. When the light is good, and you want the best image quality you can get, Quattro is equipped with Foveon sensor that can outperform a 35mm full frame sensor. Sigma Merrill cameras already have an excellent image quality and detail and Foveon ups the game even more. It is also good that the RAW files are 14-bit lossless compressed which can hold more information than 12-bit raw files. The RAW files are 19.6MP in resolution, and there is a super high JPEG option which give you Bayer equivalent 39MP image. It would be nice if the camera could produce a 39MP raw file too along with the Super Hi JPEG files, and also if it had the option to capture RAW + Super Hi JPEG.

Due to the uniqueness of Foveon sensor and the way it records information, adobe Photoshop or Lightroom cannot open the X3F raw files natively. Sigma Photo Pro is the software you need to use, either to edit or convert the X3F files to TIFF format and then process them in Photoshop or Lightroom. It is an additional step you need to consider in your workflow if you want to shoot Raw. Sigma Photo Pro is very basic and slow, but it have improved over time and with version 6.1.0, things are better than before.The software still needs some performance improvement and additional features. For example, it does not have a proper cropping tool like Lightroom or Photoshop, which is a very common feature to have for any editing software. Instead it only has fixed crop options for 3:2. 4:3, 16:9, 21:9 and 1:1. It took me some time to get used to the software, but it is not too difficult to get used to. But it itself is not enough, you will need to have other software like Photoshop or Lightroom or something similar to have a complete workflow. Sigma Photo Pro may be very basic, but it has some powerful features that are very useful with X3F files. I also found that the software handles X3F files better than Lightroom handles 16-bit TIFF files converted from Sigma Photo Pro.

For all the dp2 Quattro X3F files here, my processing steps were:

* Open the X3F files in Sigma Photo Pro 6.1.0

* Convert them to TIFF files and import them in lightroom

* Use lightroom to crop and convert to JPEG.

Once you click on a photo to open it, there is a button on the bottom right hand corner which will let you see the image to its original size.

Notes: The photos are from X3F raw files, converted to 16-bit TIFF using Sigma Photo Pro 6.1.0, imported to Adobe Lightroom 5.7 and exported to JPEG. No post-processing was done other than cropping.

As expected, dp2 Quattro delivers exceptional image quality: sharp, detailed and rich in colors. It is very rare to see a digital camera records very very close to what we see with our eyes, and usually a good amount of post-processing is needed. But Quattro actually delivered these detailed photos without any post-processing or sharpening and it is great to see a compact camera delivering image quality and detail comparable to a medium format camera.

Here are some 100% crops to show you the detail dp2 Quattro is able to resolve:

Here are some extreme 100% crops to show the amazing sharpness, detail and micro contrast the camera and the lens can deliver. And some of these photos were taken at f/2.8, which is unbelievable.

One of the night, when the sky was clear and the moon showed up on top of Duddon valley, I tried some long exposure shots with dp2 Quattro. The AF was hunting and took some time before it could focus on the moon. It also showed some color rasterization issues, even at ISO 100. It seems like the sensor is not coping well with long exposures at low light. This could be a problem with the sensor heating up or something. I am not too sure what is the reason for this. Also the lens seems to have some flare issues, but other than that the lens is incredibly sharp and can resolve a lot of micro contrast. I will ask Sigma about this color rasterization problem and see if they have an answer for me. Please note I have only experienced this on a low light long exposure, for normal use and even at higher ISOs, this problem did not repeat itself.

You can see the visible color rasterization problem in the sky, even at Base ISO 100.

dp2 Quattro is better at ISO noise handling than the Merrill cameras, mainly because of the design change in the sensor. But although the noise is better handled, the detail and color seems to get affected quite quickly, sometimes even as low as from ISO 400. ISO 800 is just about usable, but it should not be pushed higher if you expect good color detail from the photos.

If you click on the photos and go through them, you can see the differences in ISO.

Here are some more image samples of dp2 Quattro to give an idea about the image quality, color and micro contrast the can be achieved with this camera.

Image quality and detail is very important to me, and so is the life-like rendering. dp2 Quattro is not without its flaws, and it certainly is not a camera for just anyone. It requires a certain level of knowledge to know when and where to use it. But when used properly, Quattro can easily deliver a level of quality that is sometimes in the reign on full frame systems or mostly at medium format systems. But given its price and limitations, it is an ideal tool for someone who knows when and how to use it. Will I be buying one? Of course. As I said image quality and detail is very important to me. And with Foveon sensor, getting a lifelike image quality and the feel of capturing something as you have seen it is really something that I was looking for. It has its flaws, but in my opinion the image quality easily makes up for its shortcomings. A great sensor and a few shortcomings, stitched together with good intentions.

What I liked:

* Exceptional image quality, and the ability to outperform a full frame camera when the light is good.

* An unique real-life feel to the images

* Tack sharp lens even at wide aperture and from corner to corner

* Unique design which I like

* Simple menu layout

* Excellent detail in JPEG and Raw (X3F) files

* Support for 256GB SDXC cards

* Super High JPEG option at 39MP

* Faster readout speed of the sensor and buffer than Merrill cameras

What I didn't like:

* AF is fast and accurate, but slow and hunts at low light

* Long exposures causes some color rendering issues

* ISO noise handling is not the best of the class

* Raw file can only be opened by Sigma Photo Pro, no support from any third party companies like Adobe, or Capture One.

* Memory card compartment rubber door is difficult to open, and will eventually break.

* Size of the camera maybe a issue for someone

* Dynamic range loss starts at ISO 800 upwards.

Please comment any feedback or questions below, and thanks for reading.

Manzur Fahim