Casio QV-4000 Review
The QV-4000's auto white balance performed well under natural light and surprisingly well under incandescent light (where most digital camera auto wb systems fail). Also good were its pre-programmed white balance presets, each of which offered good white balance and accurate colour even under fluorescent light. Manual preset was also good, if a little blue under fluorescent light.
|Outdoors, Auto||Outdoors, Cloudy or Sunny||Outdoors, Manual|
|Incandescent, Auto||Incandescent, Incan.||Incandescent, Manual|
|Fluorescent, Auto||Fluorescent, Fluor.||Fluorescent, Manual|
Aperture Priority Mode
Aperture priority is where you designate the aperture and the camera calculates the best shutter speed, if the exposure is outside of the cameras range (either over or under exposing) the nearest shutter speed will display in red on the LCD screen. Used properly Aperture Priority can be invaluable as it has a direct effect on depth of field (the distance in front and behind the focal point which will be in focus when taking the shot).
The QV-4000 has a smaller set of apertures than some of the competition:
- F2.0, F2.3, F2.8, F4.0, F5.6, F8.0
Something else which is slightly odd, the QV-4000 reports a maximum aperture of F2.0 at telephoto, yet the lens is clearly marked as F2.0 - F2.5. This is an example of the software programmer not fully understanding the optical rules.
Aperture Priority is an exposure mode is accessed by turning the exposure mode dial to A. You can change aperture by rotating the selector dial. A basic example of aperture priority is shown below for more read my digital photography glossary:
|F2.0, 1/24 sec (Less depth of field)||F8.0, 1 sec (Most depth of field)|
Note: in the above example I did have to cheat slightly, in aperture priority mode the minimum shutter speed is 1/8 sec, thus I had to switch to manual exposure mode to achieve an F8.0, 1 sec exposure.
While usable the QV-4000's macro mode should really be labelled 'close up'. The best frame coverage was found at the 2/3 zoom position where it was possible to capture approximately 6 cm (2.4 in) across the frame.
Low Light Focus
This test measures the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.
Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).
This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.
|Lens position||Aperture||Lowest light focus|
|Wide angle (34 mm)||F2.0||<1.0 EV|
|Telephoto (102 mm)||F2.5||3.2 EV (23 Lux / 2.1 foot-candle)|
Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)
Thanks to the QV-4000's bright lens and AF assist lamp it had no problems focusing in (almost) complete darkness at wide angle and quite low light at full telephoto. With a little care and a little light you should have any problems with the QV-4000 focusing in low light.
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