So, what I see is that Sony has a 36 MP sensor a couple years old that still outperforms the 24 MP-sensors. Now, that depends on viewpoint, of course. I am a tripod shooter so I have little interest in high ISO performance for instance.
I understand, I am a tripod shooter too. I asked because my recollection was that for all intents and purposes with regards to noise the size of the pixel seemed to make very little difference when looking at images displayed at the same size, all other things (e.g. format, manufacturer and technology generation) equal. So I went back and looked at
DxO data:
![](http://i.imgur.com/inMUMVZ.png)
The only surprise there (at least to me) was the fact that the D810's could reach a lower base ISO. SNR curves (not shown) pretty well overlay each other, except that the D810's keeps going the extra little bit, as above. So what's going on? It may be informative to look at some key parameters of current FF Sony sensors on a per unit area basis, data from sensorgen.info at ISO 100:
![](http://i.imgur.com/PbjHYVS.png)
By and large the same performance: at ISO 100 all sensors shown saturate more or less at the same exposure and show roughly the same read noise and clipping in units of photoelectrons per micron squared - with perhaps the D810 a little lower than the average in both RN and FWC. DRs per unit area are directly comparable and very similar, within the margin of error. Looking at this ISO 100 chart, and ignoring resolution, there appears to be little or no difference in performance whether pixels of the Sony FF sensors of the last couple of generations are larger or smaller, as predicted by DxO's chart. But let's take a closer look at the D810 and its extended base ISO, which is substantially lower than the others'.
D810 @ISO64:
Hsat 1.66 lx-s, RN 2.49 e-/um^2,
clipping 3296 e-/um^2, DR 10.4 stops/um^2
Notice the two outlying parameters in bold above, about 50% better than their peers? They indicate a change in technology. There are reports that Sony had a patent swap with Aptina a couple of years ago, and the technology necessary for this type of base ISO extension is described in one well known Aptina patent. Incidentally, it also appears that the A7s uses a similar trick, albeit to improve high ISO performance as opposed to extend base.
So do you see why I thought that captures of sensors of the same generation using the same technology result pretty well in the same noise performance when displayed at the same size? The D810 is an outlier because it uses newer technology than the others. Hopefully it will trickle down to all other sensors by the same manufacturer as well in the future. Keep this (and shutter shock) in mind when making your choices.
Cheers,
Jack