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You are here: Home / The Last Word / Sony a7S read noise in silent mode

Sony a7S read noise in silent mode

July 5, 2014 By JimK Leave a Comment

The Sony a7S is unique among the alpha 7 series in that it has a fully electronic shutter option, called “silent mode”.

Here’s the read noise histogram at ISO 400K with the shutter in silent mode and the drive mode set to single shot:

iso 400K histo silent

The histogram is, to put it kindly, sparsely populated.

At ISO 50K, it looks like this:

iso 50K histo silent

You can make out the generally-Gaussian density function, but there is severe combing.

At ISO 25K:

iso 25K histo silent

Now the combing stops except for the 13th and 14th bits being MIA, and that funny drop out on the left side of the peak.

At ISO 3200:

iso 3200 histo silent

This histogram is tightening up nicely.

At ISO 1600:

iso 1600 histo silent

The broadening effect that we saw in single shot mode doesn’t happen here.

At ISO 800:

iso 800 histo silent

Now we get the broadening.

At ISO 100:

iso 100 histo silent

The histogram is pretty tight, but remember we’re missing the two LSB’s.

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