Sigma puts its biggest sensor in its
smallest body
While most photographers think of Sigma as
a lens maker, the company makes some genuinely unique cameras. Case in point:
the Sigma DP2 Merrill ($1000, street), a compact camera with a fixed 45mm –
equivalent (30mm actual) f/2.8 lens and 46MP (15.3MP for each color channel)
Foveon X3 imaging sensor.
This chip, used only in Sigma cameras, has
three layers of pixels, one each for the red, green, and blue color channels,
whereas traditional CCD and CMOS sensors scatter the three colors of pixels in
a single layer, usually in a pattern called a Bayer array. What difference does
this make? We’ll explain in looking at the results of our testing.
Sigma
puts its biggest sensor in its smallest body
In the test lab
In addition to the unique way Foveon
sensors capture color information, they also have the distinction of not
including an anti-aliasing filter in the optical path. While this has become
somewhat fashionable among DSLR manufacturers that are trying to court
videographers, it can cause issues in still capture. And this leads to an odd
scenario in our test lab.
For our resolution test, we shoot a target
with a pattern of lines that become ever more densely packed together. We then
determine the point at which any of the lines are no longer properly
distinguishable from its neighbors. This tells us how many lines the camera and
lens combination can resolve in the height of one image. The problem is that
the Foveon system – having no anti-aliasing filter – produces spatial aliasing,
a phenomenon that sometimes manifests itself as a moiré pattern. So, given our
strict reading of our resolution chart, the area in which aliasing makes the
lines indistinguishable is where we must mark the end of the camera’s resolving
power, though some detail beyond that is discernable.
Exposure
compensation buttons
In our test, we measured 2360 lines per
picture height – about what you might expect from a conventional 16MP
Bayer-array sensor, and about the same that we measured when we tested the
Sigma SD1 DSLR in the November 2011 issue. In real-world shooting, you can
expect more detail than our test might indicate – precisely how much is
difficult to quantify, and, we don’t think it would be appropriate to change
our test standards for this unique scenario.
Another important factor to keep in mind:
It really pays to shoot RAW with any of Sigma’s cameras. You will get better
noise results and potentially better resolving power if you take the time to do
a good RAW conversion on your files rather than relying on JPEG capture. While this
is true of most cameras, it is more so with any of Sigma’s. we always deliver
our official test results based on RAW images converted to uncompressed TIFFs
with the manufacturer’s supplied conversion software.
Strangely, although Sigma’s software doesn’t
seem to vary the amount of noise reduction applied as the ISO increase, the DP2
Merrill earned a Low rating from ISO 100 through ISO 800 before becoming
significantly more noisy (we would have expected more noise with noise
reduction staying the same). At ISO 1600, noise got a Moderate rating, and
thereafter reached Unacceptable levels. If those scores seem underwhelming,
remember that this is a compact camera. Such noise and resolution scores are
really impressive for a camera of this size.
The DP2 Merrill earned an Excellent rating
in our color accuracy test with an average Delta E of 7.9, just below the
cutoff for that rating. This makes it noticeably more accurate than most
color-negative films. So, for those photographers who want to replicate the film-shooting
experience, the DP2 Merrill can serve up the silky smooth transitions between
colors that many people love about film, while capturing more accurately.
In the field
Though the first word that comes to mind
when seeing the DP2 is “flat,” don’t let this deter you. A smattering of raised
dots on the front of the camera are surprisingly effective as a grip. At first
we were confused when hunting for exposure compensation, but we quickly realize
that the left and right buttons used to navigate the menus provide negative and
positive compensation, respectively.
Most of the settings you might change while
shooting are in the dual quick menus. Press the quick menu once and you access
the first one’s four settings, press again and you get four more settings.
Since you can use the command wheel to change the settings, you can move from
ISO 100 to ISO 6400 with one button press followed by one long quick flick of
the wheel.
As with interchangeable-lens compacts, the
manual focusing ring doesn’t move helicals inside the lens – instead, it
operates as a controller, and the lens elements are moved electronically. We
found this to be responsive and dialed in our own focus when we didn’t need the
speed of autofocus.
Given that this camera targets people who
will practice very deliberate, well-though-out photography, it’s a tad
surprising that the DP2 Merrill allows bursts of 4 frames per second. You won’t
be able to burst for all that long, given that the buffer can hold up to only
seven shots, regardless of whether you’re capturing JPEGs, RAW, or RAW + JPEG.
Unlike Sigma’s DSLRs, both of its DP-series
compacts can capture video at up to 640x480 pixels at 30 fps. While not nearly
as impressive as the 1080p that you can get from many cameras, we don’t think
that will be a problem for the photographers who will gravitate toward the DP2
Merrill. This is, after all, much more of a still shooter’s camera.
If you do decide to capture some video, you
likely won’t be disappointed. But, you likely won’t end up using it for anything
other than YouTube given the size of the capture. On the plus side, we didn’t
see any excessive artifacts in the footage we captured and the clips were
pleasingly sharp.
If you like to go out for extended shoots,
you should definitely consider getting a second, or maybe even a third battery
for the DP2 Merrill. Sigma rates the battery life at 95 shots per charge. We
had a second battery at our disposal during field testing, and ended up relying
on it many times.
The Bottom Line
While the Sigma DP2 Merrill doesn’t come
cheap – for the same price you could certainly get a DSLR or ILC, plus a nice
prime lens to go with it – the images it delivers can be downright stunning.
And while our lab tests don’t necessarily show it, in many circumstances the images
from this little camera will deliver extremely find detail with a very pleasing
overall look that some shooters feel can’t be matched by other, more
traditional, sensors.
While
the Sigma DP2 Merrill doesn’t come cheap – for the same price you could certainly
get a DSLR or ILC, plus a nice prime lens to go with it – the images it
delivers can be downright stunning.
If the 45mm-equivalent lens is not wide
enough for you, consider Sigma’s DP1 Merrill, whose lens covers an equivalent
of 28.5mm, with an actual focal length of 19mm. we received a test sample of
the DP1 shortly before our deadline for this issue and will look to provide
test data in the coming months on PopPhoto.com. But, given the vast similarity
between these two models, we don’t expect to see much difference in image
quality outside of the differences inherent in the lenses – you can likely
expect slightly more distortion from the wider-angle DP1. (For street
photographers, the DP1 would likely make more sense than the DP2, though that’s
certainly a personal decision.)
Either way, with the images we got from the
DP2 Merrill, we think that the decision to buy either of these cameras is one
that you should, at the very least, consider.
Sigma DP2 Merrill
What’s
hot
Great image quality for a true compact
What’s
not
You could get a DSLR and lens for the $
Who
it’s for
Serious shooters who want a serious pocket
camera; Foveon cultists
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Details
·
Info: sigmaphoto.com
·
Street price: $1,000
Specifications
·
Imaging: 46MP effective (approximately 15.3MP
for each red, green, and blue color layer), APS-C-sized Foveon X3 sensor
captures images with 4704 x 3136 pixels with 12 bits/color in RAW mode
·
Storage: SD and SDHC store JPEG, X3F RAW, and
RAW + JPEG files
·
Burst rate: Full-sized JPEGs (Fine mode), up
to 7 shots at 4 fps; RAW up to 7 shots at 4 fps; RAW + JPEG up to 7 shots at
4 fps
·
AF system: TTL contrast detection with 9
selectable focusing points; single-shot and continuous AF
·
Shutter speeds: 1/2000 to 30 sec, plus B
(1/3-EV increments).
·
Metering: TTL metering with 256-zone
evaluation, centerweighted, and spot (size of spot unspecified)
·
ISO range: 100-6400 in 1-EV increments
·
Video: Records at 640 x 480 pixel resolution
at 30 fps as an EVI file; built-in monaural microphone; no microphone input
·
Flash: No built-in pop-up flash; hot shoe
accepts Sigma accessory flashes
·
Lens: 30mm (45mm full-frame equivalent) f/2.8
fixed focal length lens
·
LCD: 3-in. TFT with 920,000-dot resolution;
seven-step brightness adjustment
·
Output: USB 2.0, composite video, and analog
audio
·
Battery: Rechargeable BP-41 Li-ion, CIPA
rating 97 shots
·
Size/ weight: 4.8 x 2.6 x 2.3 in., 0.9 lb with
a card and battery
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