Konica Minolta DiMAGE Z5By: Dave Etchells & Mike TomkinsKonica Minolta existing Z3 model gets an updated sensor, larger LCD and slightly updated control layout. <<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 6:OpticsReview First Posted: 03/28/2005 |
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Equipped with a 5.83-69.9mm glass lens with two aspheric elements, the Konica Minolta DiMAGE Z5's lens is equivalent to a 35-420mm lens on a 35mm camera (the lens barrel proudly reports these equivalency numbers, a nice touch, to my way of thinking). The 35mm wide angle setting equates to a moderately wide angle, and is pretty much the standard amongst similar long-zoom cameras. The 420mm tele setting is likewise almost a standard amongst 12x zoom digital cameras, and offers a very useful telephoto length that will let you tightly crop the image to your subject when you can't get close in person. It's almost certainly longer than most folks can comfortably hand-hold without image stabilization, but thankfully Konica Minolta's Anti-Shake feature helps greatly on that score. Like most digital cameras, the lens zoom operates courtesy of a rocker switch controlled motor - allowing single-handed operation, but with less precision than you might be used to if you're coming from a film SLR camera.
The lens consists of 13 elements in 10 groups, including two AD (anomalous dispersion) glass elements and two aspheric elements. All that dispersion/aspheric mumbo-jumbo is by way of explaining that this is a very high quality lens: In my testing, the camera showed good corner to corner sharpness at all focal lengths, and low levels of chromatic aberration at wide to normal focal lengths (though this did increase to a rather high level by the time I got to maximum telephoto.) Aperture control can be either manual or automatic, with a maximum aperture of f/2.8 at wide angle and f/4.5 at telephoto. Focus ranges from 2.0 feet (0.6 meters) to infinity in normal mode. Activated by a small button on the top of the handgrip, a Macro focusing mode focuses in on objects as close as about 3.9 inches (10 centimeters) to the lens surface at wide angle, and 47.2 inches (120cm) from the lens surface in telephoto mode. A Super Macro mode, which locks the lens at a focal length of 10.45mm (equivalent to approximately 62.8mm on a 35mm camera), offers focusing as close as just 0.4 inches (1cm) from the lens surface - very close indeed, although it will require care to ensure the lens itself doesn't cast a shadow on your subject matter. In my tests, the Z5 captured a very tiny minimum area of just 1.15 x 0.86 inches (29 x 22 millimeters) in Super Macro mode, with very little of the softness in the corners of its images that I've come to expect from digital camera macro modes. A plastic lens cap
with a spring-loaded catch holds onto the front of the lens barrel, protecting
it from dirt and scratches. The lens cap has an eyelet for attaching an included
strap, to prevent it from being accidentally lost.
The Konica Minolta DiMAGE Z5 provides both manual and automatic focus control. The camera's specification sheet describes the autofocus system as a "Video AF system," but it isn't clear whether it uses phase-detection focusing technology as did the Z3, or the much more common contrast-detection system. I'm suspecting that it in fact uses phase detection because it's so fast focusing, and the focusing time doesn't vary much at all as you move from wide to telephoto focal lengths. (The Z5 had full-autofocus shutter lag numbers ranging from 0.60 - 0.62 second in my tests.)
The
Konica Minolta DiMAGE Z5's autofocus system offers both Single-Shot and Continuous
AF settings, with a Full-Time AF option, as well as a Manual focus setting -
all selected through the camera's menu system. In Single-Shot AF, the camera
only sets the focus when the Shutter button is halfway depressed. In Continuous
AF mode, it adjusts focus at all times while the shutter button is half-pressed,
continuously keeping the frame in focus. When Full-Time AF is set, the camera
continuously adjusts focus when powered on. Full-Time AF is automatically disabled
when the battery warning icon is illuminated.
The DiMAGE Z5 lets you determine the area of the image the camera uses to set
the focus from, by selecting one of two autofocus options: Wide Focus Area,
or Spot Focus. The default option is Wide Focus area, indicated by a set of
two widely-spaced brackets in the viewfinder image. By pressing and holding
down the center of the Four-way Arrow controller pad, you can switch between
Wide Area and Spot Point autofocusing modes (the latter indicated by five horizontally
overlapping squares in the viewfinder). Wide Area AF bases its focus on the
most prominent subject detail in the portion of the image that falls within
the AF brackets, and in Single-Shot AF mode displays the chosen AF area with
a red square. In Continuous Mode AF, the camera is constantly focusing, so no
positive AF indication is given before shutter release. In Spot Point AF a grid
of five AF points is displayed, from which you can select the desired AF point
with the left or right arrow buttons. In the Program, Aperture-Priority, Shutter-Priority
and Manual modes, this AF point remains selected until reset by the user. In
the Auto and Scene modes, the AF point will remain selected for that mode until
the camera is powered off.
In Manual Focus mode, the up/down arrow keys adjust the focal distance
of the lens. Since the Manual Focus keys are the same as those used for Shutter
speed (in Manual exposure mode or Shutter Priority mode) or Aperture (in Aperture
Priority mode), in these modes the center button switches back and forth between
the up/down arrow keys being used to adjust Manual Focus or Shutter speed /
Aperture as relevant. As you focus, a distance readout reports the current focal
distance in meters or feet at the right of the LCD monitor (or EVF), above the
MF icon. The scale runs from either 0.1 to 1 meter, or 1 meter to infinity,
The LCD monitor also shows a magnified view from the center of the image area
that fills the entire screen, so that you can more easily fine-tune focus. The
manual-focus focus-assist magnification disappears after about three seconds
of inactivity, or as soon as you half-press the Shutter button.
In addition to the 12x optical zoom, the DiMAGE Z5 offers a 4x "interpolated" Digital zoom in 0.2x steps. When enabled through the menu system, pressing the Zoom rocker on the top of the back panel will first use the optical zoom, and then (after a brief pause) switch to the digital zoom. Keep in mind that digital zoom simply enlarges the central portion of the CCD image digitally, rather than magnifying it optically and, as a result, image resolution decreases in direct proportion to the magnification achieved.
A set of filter threads around the inside lip of the body around the lens barrel accommodates Konica Minolta's ZCW-300 Kit, which consists of a 0.75x wide conversion lens. A menu option is used to indicate to the camera that the lens is in use. With the lens mounted to the camera, a maximum wide angle equivalent to a 26mm lens on a 35mm camera can be obtained, quite a wide angle indeed.
Anti-Shake System
Originally introduced on the high-end Minolta A1, Konica Minolta's very effective vibration-reduction system made its Z-series debut in the DiMAGE Z3, and appears once again on the Z5. Konica Minolta's anti-shake technology is unusual in that it actually moves the CCD assembly to counteract camera movement, rather than the more common approach of moving an optical element inside the lens. In earlier tests comparing the performance of the DiMAGE Z3's anti-shake (AS) system against that of the Panasonic DMC-FZ15, I found that the Panasonic anti-shake system performed a bit better overall, but that the Konica Minolta approach gave a better viewfinder display without penalizing AS performance, and was also somewhat better at dealing with low-frequency vibrations. (As from your heartbeat, breathing, etc.) The Z5's anti-shake system appears to be just as good; in an informal test, I ran the camera's zoom all the way out to full telephoto, then turned on the focus-assist magnification on the LCD. With Anti-Shake turned off, it was virtually impossible to keep the resulting LCD image stable when holding the camera by hand. When I activated Anti-Shake, the results were immediate and dramatic. The image quieted down by what had to be a factor of four or more.
Anti-Shake does appear to be automatically disabled when battery life
is running low. I couldn't see this mentioned in the manual anywhere, but when
the battery warning icon is illuminated on the LCD, you are still shown the
menu options for anti-shake, but attempting to enable them has no effect. The
manual also mentions that in high ambient temperatures, the Anti-Shake system
is automatically disabled during image framing, and is used only during the
actual exposure. Presumably, the Anti-Shake system itself generates some heat,
and if used for an extended time during image preview in high ambient temperatures,
would adversely affect image quality. The manual also notes that the camera
may also use a lower ISO sensitivity than selected when Anti-Shake is used at
high ambient temperatures. Finally, do note that Konica Minolta recommends that
Anti-Shake is disabled altogether when using the camera on a tripod.
I don't know how much of a premium the Anti-Shake function adds to the cost of the Z5, but it doesn't seem to be a lot, given the camera's affordable retail pricing. Optical stabilization makes a huge difference in usability of longer telephoto focal lengths, but is a feature that has found little support from a price standpoint in the past. (Other cameras incorporating optical stabilization have generally not fared well against cheaper competition lacking the feature.) I'm hopeful though, that the range of sophisticated user that the Z5 is so obviously aimed at will understand and fully appreciate the value of Anti-Shake technology. - It really adds a new dimension to your photography, making possible a whole range of photos that would be impossible otherwise.
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