Canon's 250mp 1.3 crop sensor. Why not today?

On 10/09/2015 01:51, Whisky-dave wrote:
On Wednesday, 9 September 2015 05:02:22 UTC+1, RichA wrote:
Why is it these things get confined to ultra-expensive scientific cameras? They can obviously make them just like other sensors, so perhaps 9/10 of them are too flawed to sell? Or, not, since they already produce smaller sensors with MUCH higher pixel densities.
I would LOVE a sensor with that resolution (over twice that of a 50mp sensor).

I thought one of the problems was processing all, that information in a 'split second' so it's not the sort of sensor you'd use for sport. Perhaps record photography or even star field mapping.
I recon the cost of prodicing such a thing is probbaly what ensures that it won't be in commercail cameras.

Another problem is that at 250mp and APS-H, it's starting to become
diffraction limited at f1.2 (Airy disk max. diameter is already pixel
width).
That's arguably a good thing in terms of potential benefits of
oversampling, but in any practical sense makes that high overhead (data
processing/file size) an extreme tradeoff.

Another way to look at it is that if you want to "use" all those pixels
in a massive print, then you're going to have to use widest aperture.
Even if the lens was "up to it" with correspondingly good MTF figures
fully wide, then DOF would be so shallow in any normal photograph then
almost nothing would be in focus anyway. Of course you could take
multiple images and focus stack them, but you could also use a camera
with far fewer pixels and stitch multiple images.
If you want to capture it all in one shot, then there's no alternative
but larger sensors - but there's no free lunch there either.