Very excited about the A99

Started Sep 11, 2012 | Discussions thread
RicksAstro
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Re: What is "Photodiode expansion technology" and "Light concentration
In reply to copejorg1, Sep 14, 2012

copejorg1 wrote:

RicksAstro wrote:

TrojMacReady wrote:

robert614 wrote:

I'm hoping "photodiode expansion technology" is Sony speak for pixel binning to give better high iso performance by sacrificing resolution.

Downsampling in post has a similar effect, even with possible extra benefits.

Hardware binning could only serve a purpose for stills if the read noise was still a significant factor.

And the Bayer Matrix means you would lose color information if they hardware bin adjacent pixels.

Rick, can you explain this? Intuitively, it seems to me that hardware binning of a Bayer sensor (to, say, one-quarter of the sensor resolution -- each RGB output pixel being derived from the four photosites of a 2 X 2 RGGB cell) would result in greater color accuracy than standard demosaicing followed by downsampling to the same output resolution as with the hardware binning.

What am I missing?

Greg

Sorry for the delay...

With hardware binning, the RGGB cell would be a single HW readout, so all color information is lost. Yes, there is a small advantage under readout noise limited situations, but at the expense of the destruction of color information...not a good trade-off.

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