Originally posted by Bassat The differences between full frame and aps-c photographic results only become apparent when cropping severely, or printing HUGE. Everything you honestly believe you are seeing is marketing hype, specifically designed to get you to 'improve' your results by spending more money. Nikon did a test between the then-new D90 and whatever full frame model was current at that time. They printed poster-size (20"x30") of the same scene and displayed them on the streets, asking anyone who walked by to discern between the two. Total failure, even for seasoned photographers. It was a marketing ploy for the D90. That was at least 10 years ago. Gear, of both sizes, has improved since. For the record, I've never owned a Nikon camera.
Huge prints and deep crops aren't the only noticeable differences between FF and APS-C images. There are at least two other major side-by-side differences in FF vs. APS-C images:
1) Scenes with poor lighting and deep shadow recovery also benefit from a larger sensor.
2) Shallow DoF shooting (if you like that sort of look) is also much easier with FF.
But the biggest difference isn't in the images, it's in the viewfinder! Ask random people on the streets (and especially seasoned photographers) to look through an APS-C versus an FF DSLR viewfinder. See if they can spot that difference. HECK YA! The FF viewfinder is bigger and brighter, making it easier to compose better pictures. Sure, an APS-C camera could in theory take almost the same good picture as an FF camera, but the FF shooter has an advantage when it comes to finding, composing, and framing good pictures.
P.S. For the record, APS-C has an advantage in shooting conditions that depend on high frame-rate to increase the chance of a great shot.