With the *ist DS Pentax has created
an amateur digital SLR that combines elements from the *ist D,
a pro digital SLR, with elements that originate in its line of
compact cameras.
From the *ist D the DS model picks up all the critical shooting
modes, and some high-end capabilities such as a no-time-limit
Bulb mode, an advanced AF system, and compatibility with a number
of accessories which were originally devised for the *ist D,
but with one major exception: the vertical grip. From Pentax's
line of compact cameras, the *ist DS inherits a group of Scene
shooting modes, a remarkably simple operation that includes,
for instance, a Playback menu and compatibility with PictBridge.
Photos captured at the wide angle
end of this lens reveal an almost distortion-free image — an
image with no serious barrel distortion with a moderately distant
subject — but one which exhibits a slightly soft focus
in the corners of the frame, when inspected on a monitor at 100%
scale. Prints of the same wide angle images however, are excellent
up to a 5x7 size as the resizing that occurs to print an image
tends to sharpen it.
Immediately past the widest angle,
the soft focus disappears completely and the lens yields images
that are crisp from corner to corner. Chromatic aberration is
also well controlled, appearing only, and very minimally, on
the extreme edges of wide angle shots that contain a strong contrast
at the margins of the frame.
Much like the Nikon D70, the Pentax *ist DS has a CCD with a starting sensitivity
of 200 ISO, a slightly higher sensitivity than most cameras and one which
can often offer an advantage to the user.
At 200 ISO, the Pentax *ist DS
is often able to provide a slightly faster shutter speed than
a comparable camera with a lower sensitivity CCD would when equipped
with a comparable lens. A case in point, the photos presented
here are captured on a partially overcast and frigid day — conditions
that quickly intensify camera-shake — and the 200 ISO sensitivity
still allowed a shake-free shutter speed.
Moreover, at 200 ISO, the photos
are no noisier than would be the images from many cameras at
half that sensitivity, while higher ISO settings such as 1600
ISO, although a bit noisier, are completely useable.
The default Multi-metering is
excellent, and is able to handle complex exposures very reliably.
Furthermore, exposure compensation — usually needed with
snow photos — is precise and can be set to have increments
of 1/2 or 1/3 EV, a feature that is not commonly available.
Likewise, with this lens and left to its default settings, the *ist DS
produces images with accurate and pleasant colours.
Flash exposures are also excellent,
and the pop-up flash's coverage, particularly at the wide angle
end, is well-suited to the 18 to 55mm lens included in the kit.
The *ist DS offers 3 JPEG image
formats and a RAW format. On average the RAW format produces
file sizes that are in the neighbourhood of 11MB and, while the
RAW format ensures the highest image quality possible, it does
require the use of the software to be converted to a more useable
format, making it less expedient. The 3 JPEG formats, on the
other hand, produce an immediately useable image. Somewhat regrettably,
the format with the least compression is only available when
re-saving RAW images using the software (Pentax Photo Laboratory),
but not directly on the camera.
The highest JPEG image quality
available directly on the camera is the Best image
quality, which is described as having a compression ratio of
3:1 in the manual. Yet, the format often applies a compression
that is twice as strong, commonly running around 6:1. The very
low compression format offered through the software however does
stay in the 3:1 range, and generates image file sizes of 4 to
5 MB, a level which completely precludes the possibility of any
undesirable side effects.
The *ist DS is a very enjoyable
camera to use. Its compact size and light weight make it as practical
as many of the larger compacts, but its excellent pentaprism
viewfinder and instantaneous response to the shutter release
underline the advantage the SLR design offers without the bulk.
In our opinion, Pentax's *ist DS is a clear alternative to either the Canon
Rebel/EOS 300, or the Nikon D70 for those looking to purchase an amateur
digital SLR, and that choice may well be based on comfort and ease of use,
more than image quality.
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