Compared to...

Now we'll use the data in our review database to compare the IXUS 330's colour and resolution to three other two megapixel digital cameras: the Nikon Coolpix 2500, Minolta DiMAGE X and Canon DIGITAL IXUS 300 (the model this camera replaces).

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.

Canon DIGITAL IXUS 330 (S330) Nikon Coolpix 2500
Minolta DiMAGE X Canon DIGITAL IXUS 300 (S300)

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.

Patch Canon Digital
IXUS 330 (S330)
Coolpix 2500
Canon Digital
IXUS 300 (S300)
Black 25,25,25 27,27,27 17,18,18 21,21,21
Middle Gray 91,95,94 100,101,103 94,93,92 98,98,98
White 211,211,209 207,208,208 208,209,207 213,213,209
Magenta 205,30,115 219,39,123 206,35,81 204,38,112
Red 202,28,35 209,32,41 198,30,25 201,30,40
Yellow 209,192,24 209,197,15 217,196,65 206,193,31
Green 31,138,72 0,143,55 0,143,94 25,131,63
Cyan 12,160,224 4,161,207 0,155,229 30,155,209
Blue 26,39,111 58,47,124 43,39,76 24,30,93

As you can see colour balance from the IXUS 330 (S330) is very similar to the IXUS 300 (S300) of last year, if anything blues are slightly stronger. Compared to the other cameras the IXUS 330 seems to have a more neutral balance looking slightly less saturated than the Coolpix 2500.

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.
Canon DIGITAL IXUS 330 (S330)
Nikon Coolpix 2500
Minolta DiMAGE X
Canon DIGITAL IXUS 300 (S300 ELPH)

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Canon DIGITAL IXUS 330 Horiz LPH 820  * 1050 
Vert LPH 800  1050 
Diagonal LPH 800  900 
Nikon Coolpix 2500 Horiz LPH 750  * 1000 
Vert LPH 750  1000 
Diagonal LPH 800  900 
Minolta DiMAGE X Horiz LPH 750  * 900 
Vert LPH 700  * 1100 
5° Diagonal LPH 700  900 
Canon DIGITAL IXUS 300 Horiz LPH 820  *1000 
Vert LPH 800  1050 
Diagonal LPH 800  900 

* 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.

As we expected resolution measurements proved to be identical to last years IXUS 300 (S300) apart from a very slight increase in the point at which detail becomes extinct in the horizontal direction. This puts the IXUS 330 at the top of the pile for resolution as far as current two megapixel ultra-compacts are concerned.