Special features on board
Both cameras are built around the concept
of the sensor and the fact that image quality is key. The Pentax has a 44 x33mm
medium-format size sensor whereas the Sigma has a much smaller cropped sensor
(23.5x15.7mm). The Sigma is simple, and this is reflected in the menu system.
There are no fancy shooting settings or enhanced modes. The main feature of the
camera is the much-speculated Foveon sensor. The X3F (RAW Sigma file) is
amazing and the sensor is build up of three sensors in a stack. Each sensor
picks up the colour value form each point. Sigma status this is ‘the only
sensor in the world to really capture true colour. Just like film’ In theory it
works and in practice it’s pretty much stunning. As a word of caution though
use the Sigma Pro software to convert your files and don’t shoot in JPEG. The
amazing dynamic range of the camera gives wonderful colour rendition and breathes
new life into B&W photography.
The 645D has a 44 X 33mm sensor with 6 micron photosites
There are some downsides to this camera,
though (hopefully limited to the early generation of the model). Processing
power is lacklustre, with buffering problems. It means getting instant previews
is not an option. The battery life is not the best either, The lack of a top
LCD was a major worry at first although this soon fades. Could all these
problems be down to a power issue with the super Foveon sensor? I am not sure,
but it’s something that needs to be addressed. The Sigma is putting out 50-55MB
files-most things in life do have a trade off and in this case it’s quality for
speed.
The
SIGMA SD1 is Sigma's flagship digital SLR model
It’s pretty much the same story for the
Pentax, but at a near $10,000 over-the-counter price, the Pentax is loaded with
functions and toys. It has a shutter release, which shows you a low-resolution
file for histogram and compositional reference aside from the normal shutter
release. Dual memory card slots, GPS reprogrammable shooting modes,
dynamic-range expansion (which works very well), super-large LCD and dust
removal systems are among a few of its features. The 645D has the Hyper Program
and Hyper Manual shooting modes that current Pentax users will enjoy using.
However, my feelings are moved about the X-sync Flash mode.
The Pentax is every bit the camera you
expect it to be. However, the Sigma has one more feature worth a mention. With
a very simple removal of the dust/ IR filter, the Sigma is configured in to an
infrared camera. This makes the SD1 Merrill a hot 45-megapixel IR/visible light
camera, and the new $3,000 price tag makes it look ever more attractive. Sigma
is once again leading innovation.
Both cameras deal with lateral chromatic
aberration in a stunning way. The newer range of fluorite glass lenses from
Sigma are also a nice progression for the company and the Pentax options are
razor sharp, as we have come to expect from this brand.
Special features on board
Sigma SD1 Merrill: 8/10: a camera with innovation at its heart, although it lacks
pedigree
Pentax 645D: 9/10: Pentax says ‘As a serious tool, the 645D is second to none’ – it
isn’t wrong.
Quality of results
Image
Quality: Review of the Pentax 645D medium format digital SLR camera
Both of these cameras offer stunning
results, but they achieve them in very different ways. The 645D uses raw power
mixed with Pentax’s knowledge and imaging pedree, whereas Sigma is employing a
dynamic approach with the new Foveon sensor. Each route has plus sides and
downsides.
Both cameras are built with and
uncompromising attitude to image quality. The Pentax is easier to work and live
with by a clear margin, but both cameras offer up amazingly sharp,
well-balanced images at around 50MB. The Sigma just needs a little more
refinement when dealing with ends of the colour range.
Sigma
SD1 (Merrill) review. Sigma's 46MP
The Sigma does have more of a tendency to
blow it’s highlights, but when printed, the files are indistinguishable from
which camera they came from. However, the Sigma is near $9,000 cheaper – you
can buy an SD1 Merrill and a Jaguar X-Type 2.5V6 Sport, or you can by the
Pentax 645D. However, some could say the Pentax is cheap-how much is a
Hasselblad H4D with a 50MB back?
Using the Sigma SD1 Merrill does require a
new workflow due to the X3F not being supported by Adobe just yet. The Pentax
rival outputs to Adobe’s DNG file format. It’s very easy to see why the 645D
won then EISA Professional Camera of the Year!
When are you talking about cameras in this
sector of the market, you should only be thinking about quality. The truth is
for a price tag of less than $3,000, the Sigma SD1 Merrill gets some major bonus
point. Yes it is slow, the battery life is not great and the LCD screen is not
the best, but ask yourself what you’re really paying for? In a studio, I would
be happy to use either, and so would my clients.
Quality of image results
Sigma SD1 Merrill: 8/10: Fantastic results when used with patience and controlled in
the right way
Pentax 645D: 9/10: Stunning results and $24,000 cheaper than a Hasselblad
H4D-50
