Variable Low Pass Filter Patent from Canon

Variable Low Pass Filter Patent from Canon

Low pass filters sit in front of a camera’s sensor and help to prevent moiré in images that contain specific tightly condensed patterns. In recent years we have seen several manufacturers deliver camera’s without an optical low pass filter because it increases the sensor’s ability to produce fine detail. In some cases, like Canon with their 5Ds and 5DsR, manufacturers have made two cameras available, both with, and without the low pass filter. Most information seems to suggest that in this situation, sales of the cameras without the low pass filter have been much higher. In fact, rumors already suggest that Canon’s next iteration of the the 5DS line will no longer include the camera without the low pass filter due to comparatively weak sales from the 5Ds.

This week a patent was uncovered for a variable low pass filter. It’s a little hard to get to grips with the patent due to translation issues, but my guess would be that Canon are looking to find a happy medium between having a low pass filter, and not having one. Camera’s like the 5DS R are great for fine detail reproduction, but there is no doubt that in some circumstances they can be effected by moiré. The patent calls for some kind of “object recognition”, but perhaps this is more like pattern recognition. If the effects of a low pass filter could be adjusted based on whether moiré is likely to occur in the image, it could provide the best of both worlds.

Perhaps this is even something we will see in the 5DS R Mark II in 2017?


Variable Low Pass Filter Patent

Patent Publication No. 2016-173437 (Google Translated)

  • Published 2016.9.29
  • Filing date 2015.3.17
  • Performing object recognition using an image sensor AE sensor
  • Using a variable OLPF for false color reduction
  • Image quality decreases when focus deviation occurs is generated by the temperature, is detected object recognition is erroneous
  • It suppresses the effect of the variable OLPF according to the temperature, suppressing the influence of the deterioration in image quality

Via: Egami