FZ35和S205哪个的画质会更强一些？

The signal-to-noise ratio (SNR) indicates how much noise is present in an image, compared to the actual information (signal). The higher the SNR, the better, as less noise will be present in the image. The scale is logarithmic (in dB): + 6dB means two times less noise (as a reminder 3dB corresponds to 1 f-stop or 1EV).The SNR is here measured at the image mid-dynamic (which corresponds to a gray with 18% reflectance, commonly accepted as the average photographic scene reflectance).

Dynamic range or light sensitivity range of a sensor indicates the ratio of light exposure between the highest brightness a camera can capture (saturation) and the lowest brightness it can effectively capture (typically when noise becomes more important than signal, i.e., SNR < 0 dB). This range indicates the maximum contrast that can be effectively captured by the sensor. The larger the dynamic range, the better, as the sensor is able to capture higher-contrast scenes. Note that dynamic range is expressed on a logarithmic scale in EV (same as f-stop), thus an increase of 1EV corresponds to a doubling of dynamic range.

Tonal range indicates how many gray levels are distinguishable up to noise in an image. The tonal range corresponds to an integration of the signal-to-noise ratio (SNR) over the dynamic range of the sensor, and is therefore representative of the average noise level. The larger the tonal range, the better the image: noise is lower, and subtle nuances can be distinguished. It is expressed on a logarithmic scale as the bit depth necessary to encode that number of gray levels: an increase of 1 bit of tonal range corresponds to doubling the number of distinguishable gray levels.

Color sensitivity is an extension of tonal range that takes into account the color rendering involved in raw conversion: it basically indicates how many colors are distinguishable in an image, up to noise. Typically, if the sensor is slightly color blind, color rendering implies a strong digital color amplification and therefore a strong increase of noise. The greater the color sensitivity, the better the image: noise will be lower and with lower coloration. Color sensitivity is expressed on a logarithmic scale as the bit depth needed to encode a given number of colors: an increase of 1 bit of color sensitivity corresponds to doubling the number of distinguishable colors.

The signal-to-noise ratio (SNR) indicates how much noise is present in an image compared to the actual information (signal). The higher the SNR, the better, as this means that less noise is present in the image. The scale is logarithmic (in dB), thus + 6dB means two times less noise (as a reminder 3dB corresponds to 1 f-stop or 1EV). In the graph above, the SNR is plotted as a function of the signal (or luminance). Usually the SNR is larger for high luminance than for low luminance: this reflects the fact that noise is more present in dark areas of the image than in bright ones.

ISO Sensitivity indicates how sensitive the camera sensor is with respect to light. In terms of exposure, the higher the ISO sensitivity, the better, as less light is needed to make an exposure. However, increasing the light sensitivity (from analog or digital gain amplification) also increases the image noise. On this graph we compare manufacturer-provided ISO number (indicated in the image's Exif), versus the DxO Labs measured ISO (as defined in the ISO #12232 standard). ISO Sensitivity is also referred to as ISO Speed.

Noise covariance ellipses indicate the confusion areas around each of the 24 colors of the Gretag Macbeth Color Checker chart. A confusion area around a given color is defined as the set of colors that cannot be distinguished from that given color, up to noise. The smaller the ellipses, the better. Note that the size and the orientation of the ellipses depends on the colors: this indicates which colors are more affected by noise or by the level of color blindness of the sensor.