Compared to... (contd.)
Colour Chart Comparison
Now we can compare the C-3040Z to a few of other cameras, using samples from our test archives we will now compare its image quality to the Nikon Coolpix 990, Canon PowerShot G1 and Sony DSC-S75.
Colour charts are shot in daylight, Auto White Balance, EV compensation +0.3 (all cameras), measured light ~10 EV.
|Olympus C-3040Z||Nikon Coolpix 990|
|Canon PowerShot G1||Sony DSC-S75|
The C-3040Z produces more neutral results from our colour patches, closer to those seen from the Nikon Coolpix 990, though slightly less saturated (blue and green suffering the most). The lead in this comparison is once more taken by the Sony DSC-S75 closely followed by Canon's 'cooler' G1.
We're only measuring colour below. RGB values below were taken from a VGA reduced image (to average colours and eliminate JPEG artifacts) using the Eyedropper tool in Photoshop with a 5 by 5 Average Sample Size.
Red Channel Noise
Something we noticed early on with the current crop of 3 megapixel cameras was a certain amount of noise in the red channel, even at normal shutter speeds. This was most visible in the light blue of skies or painted walls. Our colour patch test chart turned out to be a good "leveller" and a way to measure the performance of one camera to the next.
The samples below are of 40 x 40 blocks cropped from the colour comparison charts above of the Blue and Cyan patches, each block is then broken down into it's red green and blue channels and reflected as such directly below.
Shots here are of the PIMA/ISO 12233 standard resolution test chart (more available for comparison in our comparison database). Studio light, cameras set to auto, Exposure compensation +0.7 EV for all cameras. How to read the charts: All values are 1/100 th lines/picture height/width. So the "10" value equates to 1000.
|Nikon Coolpix 990|
|Canon PowerShot G1|
Measurable findings (three measurements taken for each camera):
|Camera||Measurement||Absolute Res.||Extinction Res.|
|5o Diagonal LPH||900*||n/a|
|5o Diagonal LPH||900||n/a|
|5o Diagonal LPH||900*||n/a|
|5o Diagonal LPH||1000||n/a|
* Strong moiré is visible
Definition of terms:
|LPH||Lines per Picture Height (to allow for different aspect ratios the measurement is the same for horizontal and vertical)|
|5o Diagonal||Lines set at 5o diagonal|
|Absolute Resolution||Still defined detail (below Nyquist frequency*)|
|Extinction Resolution||Detail beyond camera's definition (becomes a solid gray alias)|
|n/a||Not Available (above the capability of the test chart)|
|n/v||Not Visible (not visible on test results)|
* Nyquist frequency defined as the highest spatial frequency
where the CCD can still faithfully record
image detail. Beyond the Nyquist frequency aliasing occurs.
About what we'd expected, the C-3040Z with its new lens is now slightly sharper than Canon's G1 and the Nikon Coolpix 990, indeed it's getting close to the Sony DSC-S75's ultra-sharp resolution, however at these high frequencies its clear to see moiré patterns in the resolution chart.