The question is inspired by [this question](https://photo.stackexchange.com/questions/9421/how-can-these-photos-have-so-high-quality) showing [these pictures](http://everyday-i-show.livejournal.com/106914.html).  

The accepted answer suggests that these pictures were taken by a 8x10 view camera, and the use of a 8x10 camera was confirmed in the comments.

My question is: How can you tell? 

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When viewed on the webpage these images are 496x620 = 0.37 megapixels (or 720x900 = 0.65 megapixels if you click for "full view").  

So any camera with a resolution higher than 0.37 Mpx should be able to capture these pictures, meaning pretty much every smartphone and webcam on the market.

I know about [Bayer sensors](http://en.wikipedia.org/wiki/Bayer_filter).
But the worst-case effect of a Bayer sensor should be to reduce resolution by a factor of four: If you downscale the picture by a factor of two in each direction, each output pixel will contain data from at least one input sensel for each of the R/G/B channels.  

Downscaling by factor 4 still means than any camera with more than 1.5Mpx resolution (rather than the 0.37Mpx of the output) should be able to capture these pictures. We're still talking about pretty much every smartphone and most webcams on the market.

I know about [color depth](http://en.wikipedia.org/wiki/Color_depth). But JPG, the format we are using to view these pictures, is 8x3=24 bits. And according to the [DxOMark scores](http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Ratings/(type)/usecase_portrait) there are several cameras, including the Sony NEX 7 and Nikon D3200, that are capable of capturing 24 bits of color.  
 So even if a $10 webcam can't quite capture the nuances in these pictures, a NEX 7 or D3200 should be able to do so.

I know that most lenses have lower resolution than what most sensors are capable of. As an example, the Nikkor 85mm f/1.4G is Nikon's sharpest lens [according to DxOMark](http://www.dxomark.com/index.php/Lenses/Camera-Lens-Ratings/Optical-Metric-Scores), and gives a best-case equivalent of 19Mpx resolution on a 24Mpx camera (the full-frame Nikon D3X), while the least-sharp lens has a best-case equivalent of 8Mpx on the same camera.   
But the worst lens in their database still gives an order of magnitude more resolution than the output format of these examples.

I know about dynamic range. But these images control the lighting so they neither blow the highlights nor lose the shadows. As long as you are in a position to do that, dynamic range doesn't matter; it will be mapped to the 0-255 output range of JPG anyhow.   

In either case, DxOMark says that several cameras with full frame or smaller sensors have a [better dynamic range](http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Ratings/%28type%29/usecase_landscape) than the best of the medium format cameras.

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That's what I know, and there is nothing in these fragments of theory that can tell me how it is possible to tell a 8x10 view camera from a Sony NEX 7 when you view the result as a 0.37 Mpx JPG. 

Essentially, as far as I understand, it should be irrelevant how many megapixels and how much color depth the sensor can capture, as long as it's at least as much as the output format can represent. 

Still, I don't doubt the judgement of the answer from Stan Rogers. And I've never seen anything similar, in terms of perceived sharpness, from small-sensor cameras.

Have I misunderstood what resolution means? 

I guess I'm primarily asking about theory: How can a difference between two resolutions (measured in pixels, lp/mm, color depth or whatever) be visible in a display format that has less resolution that either of the originals?

Or to phrase it differently: Is there anything to stop me, in principle, from replicating these pictures down to the pixel by using a Sony NEX 7 and $10,000 worth of lighting?