Sigma DP2 Merrill Review and User Experience - Part 5 - Comparison tests with Nikon, Sony and Olympus cameras

While I'm still procastinating about what I think about the Sigma DP2M overall, there is one undeniable fact about it. It has unbelievably good image quality in terms of sharpness and clarity at its base ISO of 100.

The quality of this Foveon sensor was the reason Sigma gave for the incredibly inflated price they charged for the Sigma SD1 when it first came out. It was Sigma who asserted that this sensor could give quality comparable to that from Medium Format digital cameras. Whether or not that is true, I cannot check since I don't have a MF digital camera. However I do have lots of other cameras (11 at the moment!) so that gives me an opportunity to check it out against some others. So I chose an Olympus OM-D fitted with the Panasonic 12-35mm zoom, a NEX-7 fitted with a Sigma 35mm f/2.8 and my Nikon D800E fitted a 24-85mm zoom.

Now when I processed the Sigma raw file, at the top of the page, in Sigma Photo Pro software (my only option) it had no added sharpening, as from my (limited) experience, these files don't require any. So to make it a fair comparison I processed the other three raw files in Photoshop CS6 using ACR with also no added sharpening, not even the camera raw defaults. 

But again to make it fair, Sigma have made some strong claims about the quality of this sensor, so in terms of my comparison I thought it fair to upsize / interpolate the Sigma files to an equivalent pixel size of the cameras I was comparing it with. In all cases the Sigma file was smaller.
I'll discuss what I saw here and then at the end there is a link so you can download the full size high-res. images to see for yourself.


To do this the Sigma file only required a small amount of upsizing and I was unsurprised that it looked sharper than the Olympus file. As with all the examples here, there are colour and contrast differences, but since these can be altered to taste I'm going to ignore them. We are obviously talking about a fixed lens compact camera against an extremely versatile interchangeable lens camera here, but this is just about the image quality. 

The OM-D is reputed to have a weak(ish) AA / low pass filter, whereas the Sigma doesn't have one because it doesn't need one due to the layered sensor. As you will see, if you check out the high-res, the difference isn't huge, but it is clearly there. Speaking personally I just love the "pop" of the Sigma file anyway. Not as accurate colour-wise as the Olympus but I prefer it.


Interesting comparison this, since I used the Sigma 45mm f/2.8 on the Sony, which is obviously very compatible with the Sigma lens on the DP2M, which looks like a scaled down version of the NEX lens. 

Once again despite the upsizing of the Sigma file its still sharper. Again I must make the point that the Sigma file has no sharpening whatsover. In SPP the sharpening was set at zero and I added none in Photoshop. In fact if you read Michael Reichmanns review of the Sigma in my previous post, you will see that he talks about applying "negative sharpening" to some Sigma DP2M files, and having taken a lot of images yesterday I can see where that might be required. 

From my perspective I will have no problem about upsizing the Sigma files to this 24MP size and uploading them to picture libraries. In fact I've decided on that as my default size for the camera. Not quite as mind-bogglingly sharp as at their native size but still sharper than anything equivalent. Interestingly, I looked at some Sony RX1 files yesterday, only jpgs. but I'm not sure what all the fuss is about. I'm willing to bet a DP2M file upsized looks better. Provided of course its at ISO 100.

Incidentally, if anyone is waiting for an ISO comparison on the DP2M, then you will have to look somewhere else. I'm not even going to bother to do one. The Sigma is a "one-trick pony" and I'm not moving it from its base ISO, unless its impossible to get the shot and its the only camera I have with me. Firstly, even at ISO 200 the image deteriorates far too much for me and secondly I don't see the point. This camera is designed for one thing, to provide the best IQ possible at its lowest ISO. To use it at any other setting seems such a waste. I imagine I won't even have to state that this is no way an all-round camera in any sense of those words. Low-light - forget it, fast-moving subject - forget it, high burst rate - forget it, choice of lenses - forget it. If you are looking for a camera that gives you incredibly detailed images with a top quality 30mm prime lens, when you have the time available to make sure you get it right, then this (might) be the camera for you. If you want it for the kids, holiday snaps, grab shots or street photography, get something else since the DP2M isn't designed for any of that and will not do a good job. If you want and / or need wide-angles, telephotos or zoom then you are obviously looking at the wrong review. 

It is a VERY specialist camera, and fortunately it fits in with what I do, however it can't be stated clearly enough that you have to be very sure that this is what you want. Its not SD1 launch prices, but its not cheap. Though I'm somewhat reticent to make any judgements as yet, what I will say is that its the best of its type. Though to be honest it may well be the only one of its type!!

3. Nikon D800E

Now this has required a substantial upsizing of the Sigma file, and the results are nowhere near as clear cut. However, Sigma's claims for the technology and the value they initially put on it, need this comparison to see if there is any truth in them. For Medium-Format and top of the range DSLR users, pixel count is important. Sigma saw (misguidedly in my view) a possible professional takeup of the SD1, and if this was ever going to happen then the Foveon sensor has to be capable of providing BIG files for clients. Here, ISO 100 only isn't that much of a problem. MF cameras aren't particularly great at higher ISO's anyway and its actually very rare that a photographer shooting commercially for advertising or editorial would consider anything other than base ISO anyway. Wedding photographers and reporters would use higher ISO's but I'm pretty sure that Sigma didn't have those in mind anyway, and if they did they were sadly deluded. Still life, Landscape, Architecture, Studio Fashion, Advertising and Portraiture are obvious examples of where a Foveon sensor could work well. It needs a lot of light (or a tripod) and / or a controlled environment to work in, but its not beyond the bounds of possibility that it could be considered as a "professional" option for certain situations. 

Now whether the DP2M will ever get bolted onto a tripod and pointed at Prada or Versace we can only speculate, however I think it would have to be a pretty confident and highly regarded photographer who would feel able to do that.

So how does the Sigma stand up against the Nikon? Well firstly, I should say that I bottled this a bit. I didn't want the Sigma file to be "embarrassed" so I picked a Nikon lens that isn't the sharpest I have. The 24-85mm is far from a bad lens, but lets just say I could have picked something that was slghtly "crisper".

In the end I needn't have worried. The upsized Sigma file, though demonstrating a few interpolation artefacts, stands up very well. I still think the D800E, even with the zoom is the better rendition, but the fact that I'm even considering comparing the two says a lot. For magazine and brochure reproduction, even with cropping, I really don't see much of problem in using the Sigma file. For high-end advertising, maybe there is. Anyway I'm not sure that any "pro" would take the risk. I can see how for certain commercial uses the Sigma version would be acceptable, but does it stand REALLY close scrutiny at 100% on a huge monitor? I'd be inclined to say no. 

So all in all I believe that the Foveon sensor in the DP2M is a pretty amazing thing. It does produce some wondrous looking images under certain circumstances. Its obviously not the answer to life, the universe, and everything in photographic terms but it sure beats the hell out of a lot of highly regarded cameras.(You know who you are!) If resolution at low ISO's is your thing then you may love this camera and the fact that its almost on a par with a 36MP Nikon is pretty remarkable. I don't think it lives up to claims that Sigma made for it in attempting to justify the SD1 launch price (What would??) but its still a pretty impressive piece of engineering. Unless you want to dramatically upsize the files, then its a step closer to bringing two-dimensional reality back home with you and putting it up on your screen. If thats what you want then its certainly an option.

However I would just mention battery life and viewfinder, which I'll come on to in later posts, which do tend to restrain my enthusiasm for the camera somewhat. However for low-ISO image quality I'd give it 10/10. I've certainly seen nothing better in front of me on my screen. 

Link for the high-res files - Click Here

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