According to this article from dpreview, which compared noise between a full-frame camera with a full-frame lens (the D810), the same full-frame camera with an APS-C lens, and an APS-C camera with the same APS-C lens just mentioned (the D7000), at the same aperture, shutter speed, distance, framed the same way (so I'm assuming at different focal lengths), at various ISOs, if I understand the article correctly, the article seems to suggest that the D810, that is, the full-frame camera with the APS-C lens, performs better in terms of noise than the D7000, the APS-C camera with the same APS-C lens. Am I understanding this correctly?
Here is the paragraph in question:
Now we see the effect of all the extra light captured: the outer cone in the diagram at the top of the page [this is in reference to the diagram near the beginning of the article which shows how some of the light reflected by a full-frame lens that would normally reach a full-frame sensor won't reach an APS-C sensor because of the latter sensor's smaller size]. The APS-C camera and APS-C crop still look the same but the extra sensor area (all exposed to the same light intensity [as measured by aperture and shutter speed]) allows the full frame image [to] look better overall.
I should probably also mention that according to the article, both cameras used in the test, the D810 and the D7000, have sensors with similar pixel sizes.
The reason I'm asking whether the D810 with the APS-C lens performs better in terms of noise than the D7000 with the same lens is because I'm having a hard time seeing the difference between the two test shots at various ISOs (full-frame with APS-C lens vs. APS-C with APS-C lens).
I also believe for comparison purposes, only the images taken with the full-frame camera with the full-frame lens were resized, in order to compare those images to the images taken with the full-frame camera with the APS-C lens, as well as the images taken with APS-C camera with the APS-C lens, but I could be wrong, so you might have to take a quick peek at the article.
I can clearly see that the test shots taken with the full-frame camera with the full-frame lens are less noisier than either the test shots taken with the full-frame camera with the APS-C lens or the APS-C camera with the APS-C lens, but I'm having trouble understanding why the test shots taken with the full-frame camera with the APS-C lens are supposed to be less noisier than the test shots taken with the APS-C camera with the APS-C lens, as the article seems to suggest.