snapsy wrote: ruthenium wrote:
A7V is a confusing camera.
First, if the dual output gain obscures the effect of baked-in noise reduction, then Bill Claff's replacing the inverted triangles by circles is questionable. The 1.5 DR stops difference between the mechanical and electronic shutters is surprisingly large. I am not sure this can be explained by the dual output gain alone.
THe S1 II's DGO has 1.3EV more DR than the non-DGO Z6 III even though they share the same Sony 24MP partially-stacked sensor:
A valid point.
Also of interest is that the PDR of A7V with mechanical shutter at 400 ISO is practically the same as the PDR of A7IV at this ISO, presumably with MS as well. Thus, I am not sure when and in what ISO range the DGO of A7V operates.
Edited my reply: Presumably it operates up until the dual gain ISO, since that's the point the tapering benefit would completely disappear. The only way to tell for sure would be to measure the readout time of each ISO to see where the 2x readout ends, but measuring that obviously is nearly impossible with the mechanical shutter.
I don't think the 2x read speed during ES can be measured? If the pixel values stayed the same between the two reads, then the rolling shutter effect to derive the read speed will only reflect 1x read speed. if the pixel values continue to accumulate between the two reads, then DGO is only accurate for long shutter speeds where the delay between the two reads is negligible compared to the shutter speed.
The 2x read speed is based on video mode measurements, where on the S1 II's DGO can be turned on/off with a user setting.
But what's the observation? You have double number of the bands when it's on? if that's the case, does that mean the two reads are not one read across the sensor, then another read across the sensor. Rather, one read across say 8 rows, then another read across the same 8 rows, then move on to the next 8 rows? I suppose that makes some sense. In that case, I may classify it as a single read that just take longer to process since it needs to drive both amplifiers.
Dec 12, 2025 at 11:20 AM
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