<p>Shun, you said "pixel density is an issue related to camera shake only if you blow the images up in the same way you would with a 36MP DSLR/mirrorless"<br>
When people are using a D7100 or D7200 for "reach" when doing bird in flight photography or macro photography or event photography they would be aiming at the same size prints as anyone using a D800.<br>
The smaller pixel pitch wpuld show far more movement blur with the same angular movement as a D800, and that would be more evident on the same size print made from a DX 24 MP camera image as that from a D800. <br>
You comment about an iPhone is correct but that has nothing to do with the use of the DX cameras.</p>