Olympus C-2000Z Review
Variable ISO (CCD sensitivity)
The C2000Z implements variable sensitivity in rather an interesting way. Increasing the ISO of a digital camera simply "turns up the amplifier" on the CCD output, this means that at you can work in lower light or with faster shutter speeds, the trade off is that at higher ISO levels you're also amplifying thermal noise, often shows up as noise in the blue channel (blue / yellow blotches) of the image.
Two different ways the C2000Z uses ISO: Firstly when in Aperture or Shutter Priority modes you can select the ISO of either 100, 200 or 400. Secondly in "P" (program) mode the camera automatically adjusts the ISO to produce the best results in that situation, not only that it doesn't just produce ISO's of 100, 200 or 400 but anything in-between, you can for instance get images with an ISO of 162 or 287 (as shown below).
ISO 162: 1/100s, F2.8
Measured light: 8.9EV, Exp. 9.6EV
Comparison of the same shot taken in Aperture Priority mode at F4.0, each shot was taken at the different ISO levels, as you can see the amount of noise increases as the sensitivity of the CCD is "pushed" upwards.
ISO 100: 1/40s, F4.0
Meas. 9.3EV, Exp. 9.3EV
ISO 200: 1/100s, F4.0
Meas. 9.6EV, Exp. 10.6EV
ISO 400: 1/200s, F4.0
Meas. 9.6EV, Exp. 11.6EV
That said the C2000Z produces noticeably less noise at higher ISO's than other comparable 2 megapixel digicams which means that combined with its fast F2.0-F2.8 lens the C2000Z is an excellent low-light performer and if used in Program mode allows you to quickly move between light and dark situations without having to adjust ISO settings.
The default metering mode on the C2000Z does a good job of producing an overall well exposed image, there are however some situations where you want the camera to only meter only within the center cross of the viewfinder (unfortunately this area is not represented on the LCD). This is useful in strong backlight situations such as the example below, in the first image the camera has metered an average of 9.5EV producing the exposure ISO 100, 1/160s, F2.2. Switching to spot metering the camera only meters the subject (the bottle) which it measures as 7.5EV producing an exposure of ISO 124, 1/50s, F2.2.
ISO 100: 1/160s, F2.2
Measured light: 9.5EV
Continuous (burst) mode
This rather natty (read: not that good) animation was created by putting the camera into VGA (SQ: 640 x 480) and continuous mode and just shooting as though you're using a video camera, as reported the camera managed a respectable 2fps although not directly onto the SM card, after shooting you could watch the "frames remaining" counter countdown as the captured frames were written out (maximum of 50 at VGA resolution).
Images were reduced to 160x120
and converted to an
animated GIF in Jasc Animation Shop 2.
JPEG compression modes / Uncompressed mode
TIFF: 1600 x 1200
JPEG: 1600 x 1200
JPEG: 1600 x 1200
The three 200% close-ups of an image detail above were taken at first TIFF then SHQ JPEG and finally HQ JPEG. As you can see it's very hard to distinguish between the TIFF image and the SHQ JPEG image, the HQ JPEG image is starting to show some JPEG artifacts in the flat red area below the "R" and around the scroll text, however still an image perfectly good enough for printing.
For those who are interested below is the same shot at SQ JPEG 1024 x 768 and SQ JPEG 640 x 480.
JPEG: 1024 x 768
JPEG: 640 x 480