Sunday, July 07, 2013

BSI vs FSI at 2.4um Pixel Size

DxO has tested the latest Sony Rx100 II camera featuring 20.2MP BSI sensor with 2.4um pixels and compares it with the last year Rx100 camera with identical size FSI pixels. Sony says the new sensor is 40% more sensitive to light. DxO measures a more modest 24% ISO improvement. I'm not sure if ISO is measured just in the center of the sensor, or over the whole sensor area including sides and corners. Possibly, corners could show a bigger improvement due to a better angular response of the BSI sensor.

Update: Sony posted an Youtube video comparing the older FSI sensor with the newer BSI one:


  1. Albert TheuwissenJuly 7, 2013 at 9:13 AM

    Is there any price difference ? If the two cameras are both on the market, that could be an interesting comparison too.

  2. The MSRP of BSI version is higher by $100.

  3. The difference is little more than I would expect device to device! I would have expected a 2x improvement in QE, which would translate into 2x for the ISO measurement, I think?

  4. Would it be correct to say that BSI gives better benefits over FSI for smaller pixels and for bigger pixels where the photosensitive area is already quite good, BSI may not be particularly beneficial?

  5. To answer your question about where ISO is measured, here is the target used to measure SNR. All the patches seam to be at about a 1/2 sensor length from the center.

    I checked their detailed SNR results, that confirm a 1dB improvement over RX100 (1/3 stop, or 25%).


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