Compared to... (contd.)
Colour Chart Comparison
Now we can compare the DC4800 to a few other cameras, with the samples from our archives we can now in addition to the Nikon Coolpix 880 also compare it to the Olympus C-3030Z (C-3000Z image quality is identical) and Sony's DSC-S70.
Shot in daylight, Auto White Balance, EV compensation +0.3 (all cameras), measured light ~10 EV.
|Kodak DC4800||Nikon Coolpix 880|
|Olympus C-3030Z||Sony DSC-S70|
Here we can immediately see Kodak's excellent colour reproduction, accurate and bright yet not over saturated, with a good white balance and flat tonal range. An excellent performance (which we've come to expect from Kodak Digital Cameras).
We're only measuring colour here. 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.
On the dark blue patch it's clear that Kodak do at least have the red channel noise problem better under control than Nikon or Olympus, it's there but less visible. Looking at the light blue (cyan) patch the DC4800 throws in a result about the same as the S70 with a very clean, clear result.
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 880|
Measurable findings (three measurements taken for each camera):
|Camera||Measurement||Absolute Res.||Extinction Res.|
|5o Diagonal LPH||700||n/a|
|5o Diagonal LPH||900||n/a|
|Sony DSC-S70||Horiz LPH||1050||1400|
|5o Diagonal LPH||1000||n/a|
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)|
image detail. Beyond the Nyquist frequency aliasing occurs.
As we'd expect horizontal resolution is almost identical to the rest of the 3 megapixel pack, at least the same as the 880 and C-3030Z, the S70 still manages to win here. Vertical and diagonal resolution are where the DC4800 loses out, even taking the lesser vertical resolution into account it's vertical resolution performance was relatively poor with very strong moiré all the way from about 600 lines per picture height. Moiré was clearly visible in most diagonal lines on the resolution chart and very clear to see on the center test circle: