Resolution Chart Comparison

Comparison cameras:

  • Canon PowerShot A640 (10MP, 4x zoom)
  • Canon PowerShot A620 (7MP, 4x zoom)
  • Panasonic DMC-LX2 (10MP, 4x zoom)
  • Canon PowerShot G7 (10MP, 6x zoom)
  • Panasonic DMC-FZ50 (10 MP, 12 x zoom)
  • Fujifilm FinePix S9500 / S9000 (9MP, 10.7x zoom)

Shots here are of our standard resolution chart (version one or two). This 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 15 equates to 1500 lines per picture height. (Note that on version two of our chart the vertical resolution 1000 - 2000 lines have been horizontally flipped but are otherwise identical). For each camera the relevant prime lens was used. The chart is shot at a full range of apertures and the sharpest image selected.

Studio light, cameras set to auto, settings all factory default. If possible aperture was selected for optimum sharpness. Exposure compensation +0.3 EV to +1.3 EV.

Canon PowerShot A640 (3,425 KB; 10 MP) Canon PowerShot A620 (4,630 KB; 7 MP)
Panasonic DMC-LX2 (4,821 KB; 10 MP) Canon PowerShot G7 (3,330 KB; 10 MP)
Panasonic DMC-FZ50 (4,516 KB; 10 MP) Fujifilm FinePix S9000 (4,417 KB; 9 MP)

Resolution chart crops

Canon PowerShot A640 Canon PowerShot A620
Panasonic DMC-LX2 Canon PowerShot G7
Panasonic DMC-FZ50 Fujifilm FinePix S9000
Canon PowerShot A640 Canon PowerShot A620
Panasonic DMC-LX2 Canon PowerShot G7
Panasonic DMC-FZ50 Fujifilm FinePix S9000

Measurable findings

Camera Measurement
Canon PowerShot A640 Horiz LPH 1775 2250
Vert LPH 1850 * 2400
5° Diagonal LPH +1000 n/a
Canon PowerShot A620 Horizontal LPH 1550 1950
Vertical LPH 1600 * 2100
5° Diagonal LPH + 1000 n/a 
Panasonic DMC-LX2 Horiz LPH 1600 2050*
Vert LPH 1700 2100*
5° Diagonal LPH + 1000 n/a 
Canon PowerShot G7 Horiz LPH 1775 2225*
Vert LPH 1850 2350*
5° Diagonal LPH + 1000 n/a 
Fujifilm FinePix S9000 Horiz LPH 1900 2500
Vert LPH 1850 2400
5° Diagonal LPH +1000 n/a
Panasonic DMC-FZ50 Horizontal LPH 1850 2400
Vertical LPH 1800 2300
5° Diagonal LPH +1000 n/a

* Moiré is visible
# Jagged diagonals
+ Chart maximum
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 res. Point at which all lines of a resolution bar are still visible and defined, beyond this resolution loss of detail occurs (below Nyquist frequency).
Extinction res. Detail beyond camera's definition (becomes aliased)
n/a Not Available (above the capability of the test chart)
n/v Not Visible (not visible on test results)

As mentioned in the G7 review, the A640 is well able to keep up with its pricier stable mate, and resolution is on a par with the other 10MP cameras on the market. Unsurprisingly the additional 3 million pixels give the A640 a resolution boost (in the region of 15%) over its predecessor and the results are fairly clean (not over-sharpened) until you start to approach extinction resolution when a little moiré is visible.