This second part of the Monochrom-II analysis looks at the differences between the range of ISO settings regarding noise (grain) and reduction of definition. As comparison I also looked at the same pictures made with the Monochrom-I. In both situations the same lens was used (ASC 50 mm). Not well-known is the fact that there are significant differences between the conclusions depending on the characteristics of the object that is photographed to make the comparison. There is obviously a huge difference between a picture of a landscape and a second, but different landscape and one or more portraits. That is the reason why some analysts prefer to use a testchart that is specifically designed to show image characteristics. The most common one is the USAF testchart, but the Siemens testchart is a more modern and more important pattern that is able to show differences. A classic one is the Dutch testchart devised by Dr. Tirion, which is especially critical for digital imagery. For this comparison between the MM-I and MM-II I selected the Tirion chart. At ISO 320 there are only very subtle differences to be seen. All images are enlarged to 200%! The MM-I image has less noise, but only very little and the finest details show less moiré. Note that the finest level of print is more clearly recorded by the MM-I. The finest print has very fine curves that are crisply recorded by the MM-I, but a little more diffused by the MM-II. The reproduction of the fine details in the colors blue, green, yellow and red is also better with the MM-I and the MM-II. At ISO 640/800 these differences are still visible, but now the MM-II shows an improved definition at the very fine details for the four colors. At ISO 1250/1600 the MM-II exhibits more noise, but also a better definition at the limits of resolution. Note the difference between the patterns black on white and white on black. At ISO 2500/3200 the noise starts to become quite visible in the MM-II picture, but it is still very acceptable. At ISO 5000/6400 there is hardly any change in appreciation and we have to wait for the ISO 10000/12500 to see a significant change in the reproduction. Now the MM-II shows a noise pattern that breaks up the black areas and there is also a loss of definition in the fine print.
At ISO 25000 the MM-II is still useable, but now noise is very high and definition is quite low.
Generally speaking there is hardly a difference in definition between the MM-I and the MM-II at the whole range of ISO values. Technically speaking there is not an increase in sensitivity, but only a boost in the gain at the readout-gate of the sensor. The noise of the MM-II is over the whole range higher than that of the MM-I, and the definition at the limit of resolution is for most intents and purposes identical.
The verdict from this comparison is that the MM-II does perform in the same league as the MM-I, but any one who hoped that there would be a quantum leap in image quality between the MM-I and MM-II will be disappointed.
Below: MM-I and MM-II ISO 320
Below: MM-I and MM-II ISO 640/800
Below: MM-I and MM-II ISO 1250/1600
Below: MM-I and MM-II ISO 2500/3200
Below: MM-I and MM-II ISO 5000/6400
Below: MM-I and MM-II ISO 10000/12500
Below:MM-II ISO 25000
