Detailed analysis of the Konica Minolta DiMAGE G600 images, from Imatest(tm)
I've recently begun using Norman Koren's excellent "Imatest" analysis program for quantitative, thoroughly objective analysis of digicam test images. I highly commend it to our technically-oriented readers, as it's far and away the best, most comprehensive analysis program I've found to date. (And with an introductory price of only $59, it's hard to beat.)
My comments below are just brief observations of what I see in the Imatest results. A full discussion of all the data Imatest produces is really beyond the scope of this review: Visit the Imatest web site for a full discussion of what the program measures, how it performs its computations, and how to interpret its output.
Here's some of the results produced by Imatest for the Konica Minolta DiMAGE
For the most part, the G600's color accuracy is better than average, with correct hue and saturation for most areas of the spectrum. The obvious exceptions are the reds, all of which are rather oversaturated, and some bright greens, which are just a little oversaturated. Yellows and oranges are very slightly undersaturated. The oversaturation is shown by the extent to which the circles (camera color) are displaced outward (higher saturation) relative to the ideal values (squares). On average, color saturation of swatches on the MacBeth ColorChecker(tm) chart are 109.4% of their ideal values. (An average oversaturation of 9.4%.)
In actual shooting with the G600, I found its colors to be bright but believable,
and fortunately the oversaturation in strong reds didn't translate into overly
hot skin tones. Nice-looking color overall...
These images show the color behavior of the G600 directly. In each color swatch, the outer perimeter shows the color as actually captured by the camera, the inner square shows the color after correcting for the luminance of the photographed chart (as determined by a 2nd-order curve fit to the values of the gray swatches), and the small rectangle inside the inner square shows what the color should actually be, based on perfect rendering to the sRGB color space.
Here,you can see that the luminance-correct color matches the ideal coor quite
closely in most instances.
Gray Patch Tone and Noise Analysis
There's a lot in this particular graph, a lot more than I have room to go into
here. Bottom line, the G600's noise levels are a little higher than average
across the board, but the noise spectrum is such that the noise is fairly fine-grained
and therefore less objectionable. The camera also doesn't seem to use quite
such heavy-handed anti-noise processing as many of its competitors, so there's
less subtle detail lost than in the images of many consumer digicams.
This chart compares the Konica Minolta G600's noise performance over a range
of ISOs against that of other cameras. As you can see, the G600 is somewhat
noisier than average across the board, but never to an unreasonable extent.
- The positive side of this though, is that the camera tends to hold onto detail
in subject areas of subtle contrast better than most competing models do. (This
difference is particularly evident when comparing its images with those from
the Kodak DX7630, which tends to be a little heavy-handed in its anti-noise
The chart above shows consolidated results from spatial frequency response
measurements in both the horizontal and vertical axes. The "MTF 50"
numbers tend to correlate best with visual perceptions of sharpness, so those
are what I focus on here. NOTE that there was some clipping of both white and
black values in this test with the G600, despite my having shot the res target
with the camera's contrast set to its lowest possible value. - This will tend
to distort the results, showing slightly higher resolution in the Imatest numbers
than the camera actually delivers. The uncorrected resolution figures are 1227
line widths per picture height in the horizontal direction (corresponding to
the vertically-oriented edge), and 1148 along the vertical axis (corresponding
to the horizontally-oriented edge), for a combined average of 1188 LW/PH. Correcting
to a "standardized" sharpening with a one-pixel radius increases this
number a fair bit, to an average of 1223 LW/PH. This is a little below the results
produced by the best 6-megapixel cameras, but still not bad.
For the real techno-geeks, the two plots below show the actual edge response of the G600, for horizontal and vertical edges:
G600 Test Images
G600 Imatest Results
G600 "Picky Details"
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