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Sigma SD1 / SD1 Merrill In-depth Review

April 2012 | By Andy Westlake and Richard Butler

Review based on a production SD1 with firmware 1.05, and a production SD1 Merrill with firmware 1.0

Note: Most of the material in this review was prepared using the 'original' SD1 rather than the 'Merrill' model. Sigma assures us that the two cameras are identical in all practical respects, and we've verified this in key areas of image quality, speed and operability using an SD1 Merrill. Because of this, we consider this review to apply equally to both models. In the text we've used 'SD1' to refer to both cameras for the sake of brevity.

The SD1 created a huge amount of interest when it was announced at Photokina 2010. Having used Foveon's original 4.7x3MP sensor in its SD and DP series of cameras, Sigma bought the sensor company in 2008 and instructed it to focus its efforts on high quality stills photography. The result was a 15x3MP sensor of the standard APS-C size (approx. 24 x 16mm, slightly larger than Foveon's previous designs), and it's around this that the SD1 is built.

The SD1's original pricing caused a great deal of dismay; at an RRP close to that of the professional full-frame Nikon D3X and Canon EOS-1Ds Mark III SLRs, it was placed at a level most Sigma users found entirely unattainable. However almost a year on, after what we'd assume must have been disappointing sales, Sigma relaunched the camera as the 'SD1 Merrill' with a dramatically-reduced price tag.

The SD1 Merrill still isn't cheap, though, in fact it's one of the most expensive APS-C SLRs on the market. But at a price of around £1800 / € 2100 / $2300, at least it's now in the same ball park as top end models like the Canon EOS 7D and Nikon D300s. As such, it's graduated from being a distinctly niche product to one that many more professional and enthusiast photographers might plausibly consider buying.

The SD1 is a camera with a solid specification, though not one that particularly stands out in the enthusiast-grade DSLR sector. In terms of size and body design, metering and autofocus systems, and external controls, it's most comparable to the likes of the Canon EOS 7D, Pentax K-5, Nikon D7000 and Sony SLT-A77. What it doesn't offer, though, are two features that have become standard over the past few years - movie mode and live view. We suspect that the omission of video capability may not lose it too many buyers amongst its target market, but for a high-resolution camera that would seem particularly suited to studio work, the lack of live view (and the critical focusing and composition it allows) could be a deal-breaker.

The other potential hurdle for the SD1 is its use of Sigma's own SA lens mount. The company builds a wide range of lenses for the mount, and many of them are very good indeed. But we ask ourselves how many people will be willing to risk spending money building up a collection of lenses for a non-mainstream mount. It's also worth noting that few of Sigma's lenses offer any form of weather sealing to match the camera body.

Foveon sensor

Obviously the Sigma's defining feature is its 15x3MP Foveon sensor. For those of you who haven't come across the technology before, it uses a fundamentally different method for detecting color than any other camera sensor. Almost all other cameras place a pattern of colored filters in front of their sensors so that each individual photo site is only receives either red, green or blue light. To create a full-color pixel in the final image, clever mathematics is applied to estimate the values of the two unmeasured colors, based on the amount of those colors captured by adjacent photos sites.

Foveon's technology doesn't use filters - instead it uses the fact that different colors of light can penetrate silicon to differing extents. Foveon's chip measures the number of photons captured at three different depths corresponding to how well Red, Green and Blue can penetrate the chip. The main advantage of this is that, unlike other digital cameras, the Sigma measures all three colors at every one of its 15 million photo sites, capturing three times as much color data per-pixel as a conventional sensor. (Hence the company's reference to it being a 46MP camera.)

Because the Foveon sensor captures full color data at each pixel location, it's not susceptible to color moiré - false color patterns that are the result of those clever calculations occasionally getting things wrong, for example with finely-woven fabrics. Traditional Bayer-pattern sensors suppress this by using an optical low pass (or anti-aliasing) filter that slightly blurs the image at the pixel level, reducing the camera's resolution. The Foveon sensor doesn't use an AA filter, and is therefore able to resolve substantially more detail than its pixel count alone might suggest - in principle the SD1 has the potential to produce resolution similar to a 30MP Bayer-type sensor.

Sigma SD1 specification highlights

  • 15x3MP Foveon X3 CMOS sensor
  • ISO 100-6400
  • 11-point AF sensor (all cross-type)
  • 5 frames per second continuous shooting
  • 460,000 dot LCD screen
  • Shutter capable of 1/8000th second and rated for 100,000 cycles
  • Per-lens AF fine tuning

Sigma SD1 vs SD1 Merrill - what's the difference?

Sigma says the SD1 Merrill is functionally identical to the SD1, and our experience with the two cameras supports this entirely. The only visible differences between them are that the new model has 'Merrill' written on the back of the camera and on the baseplate serial number sticker. They also require different firmware files with different version numbers, but we suspect that this is purely to accommodate the change in model name within the EXIF data.

The SD1 Merrill sports its revised moniker as a discreet badge below the LCD display. The revised model name also appears in the camera's EXIF data.

If you're new to digital photography you may wish to read the Digital Photography Glossary before diving into this article (it may help you understand some of the terms used).

Conclusion / Recommendation / Ratings are based on the opinion of the reviewer, you should read the ENTIRE review before coming to your own conclusions.

We recommend to make the most of this review you should be able to see the difference (at least) between X, Y, and Z and ideally A, B, and C.

This article is Copyright 1998 - 2015 and may NOT in part or in whole be reproduced in any electronic or printed medium without prior permission from the author.

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Total comments: 9

To update a three and a half year old review a little, as a recent convert to the Foveon sensor in this Sigma (albeit in the DP2 Merrill iteration) I can testify that the latest Sigma Raw processing software, Photopro 6.3, which is used for the SD1 Merrill as well ithe DP2, does not leave much to be desired, at least to a relative newcomer to Raw processing. And this running on Windows 7 on an ancient Core 2 Duo at 2.66Ghz with 4 Gb of memory. There may be frustrations for those who wish to devote more time to arcane debate than taking shots, but on the whole Photpro6.3 hits the spot. Hats off to Sigma....


Is this the 24-70 ART lens that you are using ? I have the 28-80 HF and 18-50DC's but the Chromatic Aberration is shocking with these and I cannot achieve a constant colour, without discoloration around the edges. I was thinking of buying an adapter and looking for a better lens, possibly a Nikon one.


Use a full frame lens like the 24-70 F2.8 EX DG HSM. You will get fantastic results. Use it properly - on a tripod at 100 ISO and F8. Have good light. Shoot raw. Convert to 48bit tiff. Edit with the appropriate skill. If the results don't blow you away, your doing something wrong.


I photograph textiles for a living and I have a love hate relationship with this camera. Some of the results are stunning, then at other times it is infuriating. The fact that I cannot Wifi the camera drives me mad,a friend is trying to solder up a device, so I can attach a ribbon cable to compact flash type 1 holder, then have a type 2 WIFI one mounted externally. I am envious of my colleague that works with a Nikon and uses her iPad to control and tether her camera, with an instant review of the post and final image .


If you shoot at 400ISO or less, use the best lenses, shoot raw and use the latest version of the much improved Sigma raw conversion software, you will be able to upsize your clean artifact free files to around 6700 pixels across giving you an equivilant resolution of a 30MP Bayer sensor. I do this all the time and the results are fantastic. Using a full frame lens on this sensor gives you images that are sharp to the corners and almost distortion free. The 24-70mm F2.8 HSM on this sensor enables image quality way beyond anything I ever shot on a 5D2 or 5D3 with L lenses.. When you get to know the tool and develop skill to use it well, the results will blow you away. Most people want it easier than that. You reap what you sew!

1 upvote

I purchased an SD1 for my business of photographing textiles in a studio situation and I feel totally deflated. The actual image quality is excellent, but the tethering capabilities are pathetic. I expected to be able to click from my PC to launch a shot, then instantly see what I had taken, before moving on to the next item, which sadly is not the case. Their software application known as Sigma Capture Pro should be reported to the trading standards council, as there is nothing 'Pro' about it as it is just a glorified remote shutter release program. Furthermore in order to have access to your images on a PC, you need to go into the menu function on the camera and disable the 'remote capture program' then select mass storage to view your images. Going through this process with every shot, may be good for you cardiovascular system, but for someone who relies on seamless throughput to make a living, this camera is junk.


Tethering capabilities? lol. You are more interested in showing off in front of clients than achieving great results. Re-align your priorities. You do realize that 90% of the time the images are used at 400 pixels wide on a web site - do you? you don't need to check each shot at 100% mag on a full size screen before you know you got it. Give us a break with your grandstanding.


I was looking at the photo comparison today, comparing the SD1 against the new Canon 5 D Mk III, the Nikon D800E, and the Pentax 645 D . . . at ISO 800 . . . and I just can not believe my eyes. Take a look at this:


The SD1 never ceases to amaze me.

Scott Greiff

Why won't the comparisons load?

Total comments: 9