I'm amazed by the quality difference of scans of real film. Some I've seen online just look amazingly good. Almost as good as seeing film projected. Some are amazingly terrible, and many are just mediocre. Why is that? Is it the equipment used?
That's part of it. But each scanner/telecine is different and requires someone who knows how to use it. It's not *just* about the hardware, though that's a very big part of it. Money isn't everything, but you simply won't get results even in the same ballpark with a $5000 scanner as you will with a $100,000 scanner. There's a reason they cost more.
In the example above, whoever scanned it either didn't use a scanner that can invert the negative, or they did it incorrectly -- so right off the bat there are going to be issues. Getting a proper positive image isn't just about flipping the colors, because color neg has an orange cast. This is why film scanners do a base calibration - to judge the density of the clear part of the image, and effectively "neutralize" it to make it properly clear. This is typically done with either a physical blue filter, or a bluer light. Once that's done, the image is inverted. But it's going to be a little different for each film stock (though stocks within the same family -- such as all the Vision3 stocks -- typically work with the same calibrations). Also, if the scan was done to MP4, that's a major red flag right there (though that may just have been a secondary viewing copy, not the actual flat scan).