A recent patent application from Canon illustrates a design that's very similar to those found in Sony's own backside illuminated (BSI) sensors. These types of sensors are typically much better when it comes to low light performance and dynamic range, even when pixel sizes are relatively small.
Cameras with BSI technology essentially have two sections that have been switched around on the sensor. Previously, sensor technology had a configuration where the photo-diodes sat behind the wiring, thus sitting further away from the optical elements in the lens. This was less efficient compared to current sensor design where the photo diodes sit much closer to the optic.
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A BSI sensor is far more efficient when it comes to capturing light and prevents any potential issues with the signal. Due to this, even high resolution cameras, such as the Sony a7R IV and the Fujifilm GFX 100, are able to maintain exceptional low light performance and incredible dynamic ranges.
The more megapixels a camera has, the smaller those pixels tend to be – as they have to inhabit the same amount of space as a lower amount of pixels. Smaller pixels tend to be less efficient when it comes to gathering light, which means they might not have very good low light capabilities. However, the more efficient structure and design in BSI sensors means that manufacturers can overcome the issues associated with smaller pixels.
Although the latest patent from Canon (via PetaPixel) does not specify that they are producing a similar type of sensor, the design similarities are striking to say the least. The photo-diodes have been switched around with the wiring on the sensor in a similar fashion to BSI sensors from Sony.
Canon is one of the few companies that doesn't use sensors from Sony, which is partly why we haven't seen BSI sensors from Canon. If this is something that Canon is working on, we may be set to see some potentially very capable cameras from the imaging company.
For some time, dynamic range was one of the main complaints for Canon cameras. This has admittedly been addressed in the latest releases from the company. However, with the implementation of BSI technology, we may see even greater improvements in this area yet.