Canon has filed a new patent: a neutral density filter for only half the field to expand the dynamic range.
Introducing a neutral density filter for only half the field, you get differing amounts of light to AF pixels that are split on the same axis as the filter. This would increase the differential output of the sub-pixel pair as you pass through sharp focus.
Patent Publication No. 2015-87401 (Google Translated)
- Published 2015.5.7
- Filing date 2013.10.28
- Dual Pixel AF
- And set up a half-ND filter at the pupil position of the lens
- Half ND filter can be switched
Canon patent application incorporates a half ND filter to the lens side, one in the light of the plain of the sub-pixels, on the other hand and by receiving the light dimmed, is that to expand the dynamic range. Even if you do not require a high-speed AF in video and live view, it is going to be a reason to actively choose the DPAF.
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