X-Trans CMOS Sensor, installed for the first time in premium interchangeable lens camera FUJIFILM X-Pro1, had the optical low pass filter, previously placed in front of the sensor, removed. To maximize the resolution capable by the lens, the function of reducing moire and false colors previously handled by the low pass filter were realized by pixel distribution and signal processing.
By using a structure without a low pass filter, high image quality surpassing those of single lens reflex cameras with 35mm full frame sensors was realized. This achievement was highly praised by many of our customers.
But at the same time, further efforts were being made toward realizing even higher image quality. The issue tackled was diffraction which inevitably occurs for all optical lenses during magnification. When more delicate subjects (high frequency subjects) are taken at a lower aperture, they appear out of focus when they should not. This is due to light expanding like waves while the photo is being taken. Even if the photographer zooms in and increases the depth of field to achieve an evenly sharp resolution, diffraction makes the finished product turn out entirely out of focus instead. The smaller the size of the sensor and the higher its pixel count (or the narrower its pixel pitch), the more likely that diffraction will occur.
The technology newly developed as a solution was signal processing by the optimization filter which matched the characteristics of each lens. This is the Lens Modulation Optimiser technology which restores an out-of-focus image into its original state.
The optimization filter (a type of signal processor) used for the Lens Modulation Optimiser was designed encompassing the focal length and aperture for each lens, as well as data from the center of the screen to its edges, and including calculations. This enormous amount of data requires just as much know-how to handle its processing. These were made possible because Fujifilm develops all of its lenses, sensors and processors. Advances in signal processing circuit technology allowed this achievement to finally become a reality.
Lower apertures can be used without worry thanks to the Lens Modulation Optimiser technology, even for scenes that could not be stopped down. As for situations that make you hesitate to zoom in all the way for fear of diffraction, this technology allows you to use apertures up to F16 for FUJIFILM X100S (fixed single focal length lens) and up to F8 for FUJIFILM X20 (zoom lens), providing ample opportunity to show the function of their lenses. Combined with X-Trans CMOS II Sensor's high image quality which does not require a low pass filter, this allows you to take crisp images whether the diaphragm is fully open or almost closed
The role of the image processing engine, EXR Processor, is to process the signals received from X-Trans CMOS Sensor, in which 6 x 6 pixels are regarded as one unit, to intricately create images. With the introduction of phase difference pixels to X-Trans CMOS II Sensor, the image processing engine was also upgraded to EXR Processor II with greater roles to offer improved processing ability and speed.
In digital cameras, signal processing performs five major operations:
Much like the improvement of a computer's CPU capabilities, the processing of these operations must be sped up as well. With EXR Processor II, the capability of the EXR Core is double(*1) that of its predecessor. Said Core comprises the heart of the processing circuit. “Pipeline Processing” was also realized, where processing for certain consecutive tasks (e.g. AF/AE detection→loading of data received by sensor→image processing→compression into Jpeg→recorded onto card) are performed completely at the same time. Thus, image processing speed has been increased by reducing the wait time between the end of one process and the start of the next process. Furthermore, a dedicated circuit has been installed for phase difference AF. Changing this operation from software processing to hardware processing has also contributed to the improvement in AF performance.
Shutter time lag
Shutter time lag
Thanks to these vast improvements in processing technology, both the time between shots and the continuous shooting speed have become equal to those for professional single lens reflex cameras with full size sensors. The frame rate for full HD videos has also improved from 30fps, to 60fps.
EXR Processor II is an image processing engine with both high image quality and speed, made possible by redeveloping basic structure with renewed research into image quality, speed and other functions expected of the X series.
This camera provides the highest image quality and speed so that users can take the best photos under any conditions. This quality is what is demanded in Fujifilm products. Our basic stance of improving our unique technologies while striving toward better image quality remains unchanged.
Processor development project leader: Hiroyuki Kurase, Senior Engineer
Processor development leader: Kenichiro Tominaga
Processor algorithm development: Seiji Tanaka
Lens Modulation Optimiser technology project leader: Masaya Tamaru, Senior Engineer