Compared to... (contd.)

Now we'll compare the DiMAGE S404 to a few other cameras from our test archives. Here we're comparing colour and resolution to the Minolta DiMAGE S304, Canon PowerShot G2 and Sony DSC-S85.

Colour Chart Comparison

Colour charts are shot in daylight, Auto White Balance, EV compensation +0.3 (all cameras), measured light ~10 EV. This test is also dependent on the accuracy of the camera's auto white balance, the colour charts are shot in daylight but some camera's white balance is better than others. All cameras are given 20 seconds to "settle" before the shot is taken.

As per other samples in this review the S404 image has been converted to the sRGB colour space using the Minolta Image Viewer application [info]

Minolta DiMAGE S404 (Resaved as sRGB) Minolta DiMAGE S304 (Resaved as sRGB)
Canon PowerShot G2 Sony DSC-S85

Notice the clearly blue cast white balance, after taking my first test shot I went back and retried this a few times but always go the same result. The S404 does seem to have a tendancy to produce a bluer white balance than the other cameras (this has the effect of making whites look whiter).

In the table below we're only measuring colour. The RGB values were measured from a VGA reduced image (to average colours, remove noise and eliminate JPEG artifacts) using the Eyedropper tool in Photoshop with a 5 by 5 Average Sample Size.




PowerShot G2
Black 15,19,22 27,31,34 45,43,42 17,17,19
Middle Gray 70,72,87 82,93,95 107,106,110 76,81,79
White 192,191,201 217,221,221 208,210,208 188,189,189
Magenta 179,26,106 215,53,115 196,37,116 170,12,124
Red 176,29,44 211,54,48 195,30,35 176,0,40
Yellow 189,190,34 212,216,37 205,195,20 181,180,14
Green 3,113,45 16,134,64 43,152,68 24,131,27
Cyan 8,123,194 1,144,208 23,169,234 23,158,175
Blue 31,21,94 42,32,101 61,56,133 23,31,112

Resolution Comparison

Shots here are of the PIMA/ISO 12233 standard resolution test chart (more of which are available in our comparison database). This resolution chart allows us to measure the actual performance of the lens and sensor system. It measures the ability of the camera to resolve lines at gradually higher resolutions and enables us to provide a definitive value for comparison purposes. Values on the chart are 1/100th lines per picture height. So a value of 8 equates to 800 lines per picture height.

Studio light, cameras set to auto, all settings factory default. Exposure compensation +0.7 EV for all cameras.

Horizontal resolution Vertical resolution 5 degree diagonal res.
Minolta DiMAGE S404
Canon PowerShot G2
Sony DSC-S85

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Minolta DiMAGE S404 Horiz LPH * 1150  * 1350 
Vert LPH * 1100  * 1350 
5° Diagonal LPH 800  n/a 
Canon PowerShot G2 Horiz LPH 1250  * 1450 
Vert LPH 1200  * 1500 
5° Diagonal LPH 1000  n/a 
Sony DSC-S85 Horiz LPH 1250  * 1650 
Vert LPH 1200  1650 
5° Diagonal LPH 1000  n/a 

* 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)
5° Diagonal Lines set at 5° 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.

The DiMAGE S404 performs fairly well, clearly it's not quite up there with the best, although vertical resolution is closer than horizontal. What is much more noticeable on the S404 is the strong yellow / blue colour moiré as line frequency enters the camera's limit. Interestingly the S404 suffers worst on the 5° diagonal pattern where it produces moiré.