Olympus EVOLTE E-330 digital camera
On January 26th 2006 over a year since the introduction of the E-300 Olympus revealed the 7.5 million pixel 'live view' successor, the E-330. The E-330's biggest differentiation to any other digital SLR is its capability to deliver a live view on the LCD monitor (in the same manner as a prosumer / consumer all-in-one digital camera). For those new to digital SLR's this is difficult to achieve because of the mirror / shutter mechanism, the mirror is in the light path in view mode to provide an image to the viewfinder, this means that no image can be projected onto the main sensor. Additionally most large D-SLR sensor don't have video out capability. Other changes over the E-300 include a flip-out LCD screen and a range of feature improvements inherited from the E-500.
The E-330 achieves live view in one of two ways; in A Mode ('Full-time live view') the mirror stays in place and you can continue to use the viewfinder, the live view image is produced using a small secondary CCD sensor in the viewfinder chamber (as suggested by me five years ago). In B Mode ('Macro live view') the mirror flips up, the shutter opens and the live view is provided by the E-330's unique 'Live MOS' sensor. There are significant differences between the two modes:
FeaturesThe Live MOS Sensor offers image quality comparable to a Full Frame Transfer (FFT) CCD sensor with the low power requirements of a CMOS sensor, and is noteworthy for its high-quality imaging capabilities over an extended period of time. Simplified circuitry that reduces the distance from each photodiode to its corresponding on-chip microlens assures excellent sensitivity and image quality even when light strikes it at a high angle of incidence.
- Resolution: 7.5 megapixels, with excellent low-light performance characteristics.
- Grain: low-noise technologies assure reduced graininess.
- Tonal range: Simplification of the transfer register and other circuitry results in a large photodiode surface area for FFT-CCD-level sensitivity and responsiveness.
- Low power consumption: Power requirements are approximately half those of FFT-CCD sensors.
- High speed: Simple circuit structure contributes to faster processing overall.
Redesigned Sensor Elements with Greater Photosensitive Surface Area
The Live MOS Sensor takes advantage of the simplified circuit requirements and thinner layer structure of NMOS type sensors to offer a larger photosensitive surface area. In addition, circuit technology refinements were made to boost light utilisation efficiency and improve image quality.
A new transfer mechanism for photodiode signal readout enabled us to reduce the number of circuit paths to two, the same as in a CCD sensor, and thereby minimise the surface area that is unresponsive to light. By effectively enlarging the photosensitive surface area and enabling it to capture light that was previously lost, we were able to achieve both high sensitivity and superior image quality. We also developed a new low-noise photodiode signal amplification circuit to further improve sensitivity.
Low-Noise Technology for Significantly Improved Imaging in Low-Light Environments
A dedicated processing technology developed for use in 5V (design specifications: 2.9V) low-voltage systems is employed to significantly reduce noise. Operating signal noise was also considered, and the sensor photodiodes were deeply embedded in silicon to isolate them from noise-causing elements on the chip surface. As a result, images are clearer, and the graininess and white noise that often appear when shooting in low light are suppressed. Thanks to this technology, low-light performance is improved overall, and a clear image can be obtained even when shooting in very dim light.
Color space
The E-330 provides the independent selection of output color space, you can select from sRGB or Adobe RGB. Sadly, just like with the E-300 and E-500 this option is buried away on the second setup menu (why it can't be on the first menu with the other image parameter options is beyond me).
Images taken in the Adobe RGB color space have their filename prefixed with an underscore (_) this complies with DCF 2.0 (Exif 2.21)*. It looks as though Olympus has fixed the color space issue we discovered in our E-300 review, color response is virtually identical between the two modes (apart from Adobe RGB offering a wider gamut and slightly more contrast). Place your mouse over the label to see a ColorChecker chart shot in the respective mode. (Picture mode Natural used for these samples).
* This has nothing in particular to do with Olympus but this renaming system makes it difficult to keep your images in the correct order if you don't routinely rename them by date/time.
Color space: CIE u'v' Color Distribution chart
Note that in these samples the Adobe RGB image has not been converted to sRGB and so to view it correctly you will have to load it into a color space aware photo application and assign the Adobe RGB color space. (Picture mode Natural used for these samples).
Below each sample is the CIE u'v' Color Distribution chart; larger gray triangle approximately represents the range of color which the human eye can resolve, the inner triangle the available gamut in each color space (sRGB or Adobe RGB).
posted by digicam at 2:54 AM
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