This camera would have a pixel density equal to a 61mp full frame camera, that is far beyond the resolving power of most lenses.
Grrrrr....would people quit saying entirely wrong stuff like that please? First of all resolving power doesn't work like that. Second, even if it did the better lenses can already resolve up into the many hundreds of megapixels on full frame.
Yes, but diffraction softness at this pixel density starts to become a problem, get up to f/5.6 or higher and you start loosing sharpness.
Diffraction is the most misunderstood concept in photography. The notion that diffraction is ever a "problem" is just flat out wrong. Just because diffraction starts earlier
with smaller pixels does NOT
mean you are resolving less detail. The amount of detail resolved by the lens is fixed, and independent of the sensor. Assuming a 24mp sensor outresolves the lens while an 18mp sensor does not, no matter how you slice it, even when diffraction blur starts, the 24mp is and always will be resolving more detail than the 18mp. If you scale the 24mp sensor image down to 18mp image size without any additional processing, the 24mp will always be sharper (assuming focus, aperture, etc. were all configured identically between the two cameras.)
Diffraction is the fault of the lens, not the sensor...both the 24mp and 18mp sensors are experiencing the exact same amount of softening due to diffraction...it is simply that the 18mp is PHYSICALLY INCAPABLE of actually demonstrating that fact, while the 24mp IS CAPABLE. A 22mp sensor would be somewhat capable of showing you that diffraction, however it would not be as good as the 24mp, and still, no matter how you slice it, the 24mp sensor (all other factors being equal) would STILL be resolving more detail, even if its slightly softer than the 22mp. Even if that additional detail just means the circumference of the blur circle is better defined.
I really have to emphasize this: In no way, ever, can diffraction produce worse results on a higher resolution sensor than a lower resolution sensor. EVER. Even if, at 100% crop, the detail looks a little soft on the higher resolution image, it will in the worst case be just as good as the lower resolution sensor on a size-normal basis, and in the majority case normalizing size will always make the higher resolution image look better than one taken with a lower resolution sensor.