In part 2 of the Sigma DP2 shootout, we'll look at how the DP2 lens performs at a variety of apertures and compare the overall detail captured by the DP2 with that of the Panasonic GH1 and Olympus M. Zuiko 17mm f/2.8 lens.
To begin, I'll explain my choice of RAW processors. The DP2 files were processed using Sigma Photo Pro (latest version) because there are no other RAW processors which demosaic DP2 files at this time. The GH1 files, on the other hand, can be processed using a number of different applications. I chose to use Adobe Lightroom (latest version) because it automatically addresses the considerable barrel distortion of the M. Zuiko lens. In doing so, one loses some resolution, and the blurriest extreme corners of the image get cropped out, but overall I think it gives the fairest comparison to the Sigma DP2.
How much do processing decisions affect apparent detail? Here's an example of an f/2.8 center 100% crop processed with Lightroom (right) compared to the same file processed for maximum apparent detail in Raw Developer (left):
Most of the difference there comes down to sharpening, though I do find that Raw Developer squeezes out a touch more detail. This is true for every camera I have tried to date.
Other testing details:
Subject distance adjusted for roughly the same framing with each camera (greater distance for the longer lens)
GH1 used in 3:2 aspect ratio
DP2 files upsized using Genuine Fractals 5 to match the native GH1 picture dimensions
Tripod, self-timer, base ISO, aperture-priority exposure, good light (high shutter speed)
Even looking at just the resized left half of the scene, there is a clear difference between the DP2 and GH1-17mm files at f/2.8:
Let's look next at the 100% crop comparisons, keeping in mind that the DP2 files have been upsized to match the GH1 file sizes.
f/2.8
Center:
More detail in the GH1 file as would be expected with the higher megapixel sensor.
Near edge:
DP2 outclassing the M. Zuiko here and also showing greater lens contrast. There is some color fringing in the GH1 crop.
Extreme corner:
Impressive wide open performance from the DP2 in the extreme corner of the frame while the M. Zuiko lags far behind. Again there is some color fringing in the GH1 crop.
f/4
Center:
GH1-17mm looking very good here with the lens resolving sufficiently to take advantage of the higher megapixel sensor.
Near edge:
Zuiko has caught up here in peripheral performance.
Extreme corner:
The Zuiko has improved but has a ways to go still.
f/5.6
Center:
As expected, the higher GH1 sensor is still capturing more detail at this aperture.
Near edge:
Still very close in this zone.
Extreme corner:
DP2 still has an edge in the extreme corner.
f/8
Center:
GH1-17mm still has an edge, but diffraction is bring the level of detail down closer to that of the DP2.
Near edge:
DP2 looks the better of the two here.
Extreme corner:
DP2 is clearly better.
Conclusions:
The Sigma DP2 lens has balanced performance across the frame wide open at f/2.8, and by f/4 even the extreme corner peformance is quite good. Anything less would have been a disappointment given the precedent set by the outstanding DP1 lens.
The M. Zuiko 17mm lens leverages the GH1 sensor potential in the center of the frame from f/2.8, puts in a decent peripheral performance stopped down to f/4 or f/5.6, but never quite nails the extreme corner.
Softening due to diffraction is evident at f/8 with the Micro Four Thirds kit and not with the DP2.
There seems to be higher lens contrast with the DP2 although the contribution of processing by Sigma Photo Pro cannot be ascertained. Application of wide-radius unsharp mask to a GH1 file gives it a similar look to that of the DP2 files.
Update: Great news, Olympus will be providing an E-P1 kit for the shootout! Not surprisingly, E-P1 kits are on short supply right now, so it will be a while before we get one. Nevertheless, this will be the most thorough shootout yet, assuredly worth the wait! Many thanks again for the community support, via posts and tweets, without which this likely wouldn't have happened.
Thanks to everyone who commented on the previous post. With your help, we got the attention of Sigma, and they have agreed to provide a DP2 (hopefully with VF-21 viewfinder and HA-21 converter) for the shootout. Here they are announcing it on Twitter:
Very cool of Sigma to step to a direct shootout like that! So far, there is no definite commitment from Olympus. Two Olympus representatives on Twitter responded to my request by asking me to direct message them with my contact information. I did so yesterday and am waiting for them to get back to me.
I'm sure that their review units are in short supply so soon after the launch. Hopefully Sigma's willingness will inspire the Olympus folks to provide a test E-P1 and 17mm kit for the shootout. I don't think there is any more well defined market for these cameras than the one we represent.
If anyone would like to help lobby Olympus on Twitter, direct your tweets to @cjleonejr (Olympus PR) and @getolympus while mentioning #seriouscompacts so that I can keep track. Thanks again everyone!
I'd like to gauge interest in the possibility of another shootout. I was thinking that a comparison of image quality (center and corner detail, dynamic range, high ISO performance, flare resistance, color fringing, etc) from RAW using an "impartial" converter such as dcraw is currently lacking amongst the various sites which are currently testing advanced compacts. The ones which do examine RAW files all seem to use Adobe Camera Raw, which applies different amounts of sharpening and noise reduction to different cameras.
The purpose of the following poll is to help me gauge general interest in such a shootout as well as specific interest in various cameras. I have access to a number of these cameras, but time to perform testing and analyze/present results is limited so I'd like to focus on just two or three of them. Most of the testing will be at the 28mm angle of view (in 35mm photography terms).
Thanks to all who have participated in the poll. Based on the results so far, I am planning a shootout with the Sigma DP1, Ricoh GRD II, and Canon 5D, beginning as soon as I receive the DP1. If I can stretch the budget a bit, a Canon G9 may find it's way into the shootout (but no promises).
Addendum - Due to the early availability of the E-420 & 14-42mm kit, this camera will be included as well. Unfortunately that stretches our working budget, and we may not be able to include the GRD II in the shootout. More on that later...
Having pre-ordered the DP1, I'm working towards doing a shootout along the lines of the GX100 vs G7 vs D-LUX 2 Shootout. The issue is that there really isn't another camera like the DP1. The GRD II is probably the closest match from the standpoint of a photography tool, but others will likely do that comparison. Professional photographer and reviewer Sean Reid will no doubt do a thorough job of comparing the two when he does his DP1 review. Pavel Kudrys of Ricoh Forum has posted a number of excellent GRD II tests and has stated his intent to try to obtain a DP1 for comparison. Nevertheless, I'd be willing to add my comparisons to the mix. Alternatively, I could do a comparison of the Canon 5D and EF 28mm f/2.8 lens to the DP1, but that is unsatisfying for three reasons. First, the 5D is massive compared with the DP1, so they obviously serve different functions. Second, the 5D is a good deal more expensive; and third, the SD14 (which has the same sensor as the DP1) has already been compared with the 5D. The Canon G9 is a reasonable camera for comparison since it offers excellent image quality, RAW, and is only moderately larger than the DP1. It seems to be the compact carry of choice for a number of folks who are serious about photography. The main downside is that the G9 lens doesn't go wider than 35mm (equivalent). The upcoming Canon Rebel XSi/450D is an attractive candidate for the shootout since it is priced close to the DP1 and has a kit lens that goes to 28mm (equivalent). I'd be interested in seeing the DP1 compete against a 12MP, recently-announced entry-level DSLR. I'd choose the Canon over the Nikon equivalent simply because I already have a couple Canon lenses I could use with it. The downside, again, is that an XSi isn't compact. It also won't be available for testing until mid-April at the earliest. The Leica D-LUX 3 and its equivalent, the PanasonicLX2, are also under consideration. These are excellent cameras which offer wide angle, RAW, and, like the G9 are frequently the compact choice for serious photographers. The GX100 also deserves consideration but is off the list since the best comparison from Ricoh is almost certainly the GRD II. The Olympus E-410 with 14-42mm kit lens, as the most compact DSLR available, is another comparison some may find of great interest. The Olympus Stylus Epic is an old 35mm film compact with a 35mm f/2.8 fixed focal length lens. It would make for an interesting comparison, but somehow I doubt that many folks will have trouble deciding between this one and the DP1.
Perhaps you have a better suggestion, or maybe you think that a shootout would be pointless since the DP1 represents a new class of camera. Kindly let me know by responding to the poll featured to the right as well as by leaving your comments below. The poll restricts each individual to a single selection. The reason for this is that I have neither the time to test nor the money to buy all those cameras! I'm simply considering buying and/or borrowing one or two (max) for the purposes of a shootout and would like to get a sense of where the general interest lies. Thanks!
