MONOCHROME SENSOR - WHAT IS THE DIFFERENCE

A lot has been said about the new Leica M Monochrom and, as usual, opinions differ.  However, one fact has emerged that cannot be argued.  The performance of the new camera is quite amazing.  Even though the sensor of the camera has the same 18 megapixel resolution as the M9 and M9-P, overall sharpness and tonal range is visibly better.  How is that possible?

The main difference lies in the fact that the Leica M Monochrom sensor is strictly black and white.  Just as with the M9 sensor, the manufacturer is Truesense, the former sensor division of Kodak.  Color sensors need to employ a lot of tricks and compromises in order to deliver a color image with full resolution.

In front the sensor requires the installation of a screen of color filters.  Each pixel is covered by either a red, green or blue filter.  Subsequently each pixel records only the color values of that particular filter.  In order for each pixel to generate all colors, the missing colors are transferred from the surrounding pixels by interpolation.  The image processor of the camera then has to find a compromise between resolution, noise and interpolation artifacts.  All these steps adversely affect resolution, sensitivity and indirectly, noise.

Since a monochrome sensor doesn’t have to deliver color values, the filter screen is unnecessary and image information is generated without interpolation and its subsequent compromises.  This enables the sensor to deliver full resolution.

Even though the sensor of the Leica M Monochrom has the same 18 megapixel resolution as the M9, it is capable of noticeably better performance.  Higher resolution and detail sharpness through the elimination of interpolation, higher sensitivity and less noise because no light is absorbed by the filters.

Additional advantages are no need to white balance.  Instead the image files can be directly recorded as toned black and white images in varying amounts.  Available are blue, selenium and sepia.

The entire range of ISO values has been shifted.  The maximum ISO value is 10,000, compared to 2,500 with the M9.  Minimum ISO value is 160.  However, that is considered a ‘pull value’ which results in lowered contrast.  For optimum results Leica recommends ISO 320.

Following are images taken with the Leica M Monochrom.

Test of resolution:

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	The detail of the wall is achieved without any further manipulation. Click on picture to enlarge

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	The point-like structures of the plant are resolved at individual pixel level. Click on picture to enlarge
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Test of high ISO performance:

	Taken at ISO 8,000. Click on picture to enlarge
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	Taken at ISO 3,200. Click on picture to enlarge
	Even the surface of the water shows no noise at all. Click on picture to enlarge

Test of range of contrast and tonal range:

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	Lightened to show the incredible amount of detail maintained in the shadows. Click on picture to enlarge

All Pictures courtesy of Andreas Jürgensen of Systemkamera-Blog