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Compared to... (contd.)

Now we'll compare the Nikon Coolpix 4500 to a few other cameras from our test archives. Here we're comparing colour and resolution to the Canon PowerShot G2, Sony DSC-S85 and Minolta DiMAGE S404.

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.

Nikon Coolpix 4500 Canon PowerShot G2
Sony DSC-S85 Minolta DiMAGE S404 (Resaved as sRGB)

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

Nikon
Coolpix 4500

Canon
PowerShot G2
Sony
DSC-S85

Minolta
DiMAGE S404

Black 25,27,27 45,43,42 17,17,19 15,19,22
Middle Gray 101,100,102 107,106,110 76,81,79 70,72,87
White 211,210,209 208,210,208 188,189,189 192,191,201
Magenta 203,38,118 196,37,116 170,12,124 179,26,106
Red 189,22,43 195,30,35 176,0,40 176,29,44
Yellow 193,183,27 205,195,20 181,180,14 189,190,34
Green 29,140,61 43,152,68 24,131,27 3,113,45
Cyan 60,167,205 23,169,234 23,158,175 8,123,194
Blue 54,47,112 61,56,133 23,31,112 31,21,94

As you can see the Coolpix 4500 has a very similar colour response to the G2 albeit with slightly lower saturation (this can easily be increased if you prefer). The 4500's black point is also about half way between the G2 and the other cameras, this is a good balance between images which look too flat and loosing information at the darker end of the greyscale. (Note: Unlike some early adopters of the camera I don't see, nor have I seen in my samples, a problem with reds and the Coolpix 4500).

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.
Nikon Coolpix 4500
Canon PowerShot G2
Sony DSC-S85
Minolta DiMAGE S404

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Nikon Coolpix 4500 Horiz LPH * 1200  * 1350 
Vert LPH 1100  1300 
5° Diagonal LPH 1000  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 
Minolta DiMAGE S404 Horiz LPH * 1150  * 1350 
Vert LPH * 1100  * 1350 
5° Diagonal LPH 800  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 Coolpix 4500 exhibits good horizontal resolution but less vertical resolution than we would have hoped for. That said it does so without any noticeable artifacts and only some mild moiré on the horizontal resolution bars. Note the difference between the way the G2 has over-sharpened the 5 degree diagonal patch and the way the 4500 reproduces the same area.

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