His reference is 35mm film. The size of a 35mm image is the size of the sensors used in the top end DSLRs. This was done so that all those legacy lenes could still be used. Makes sense. But in the beginning they were very expensive to make. The reject rate of full size sensors was very high. It probably still is high in comparison to smaller sensors such as an APS-C sensor.
From Cropped Sensor To Large Sensor Compact
Now with the release of the new Leica X Vario Type 107 Thom now calls the APS-C sensor a Large Sensor Compact. Thom says the camera will cost &2,850.00. Maybe that's why he includes LARGE in the description of the sensor. Large price anyway.
Same sensor, APS-C, different definition. Strange.
Another blogger, who will remain nameless, called the APS-C sensor a reduced sensor. Maybe because he spent a small fortune on the purchase of a Nikon D800. A Nikon D800, body only, cost $2,796.95 at B&HPhotoVideo and that includes a $200.00 instant rebate. At the discounted price the body only Nikon D800 cost less than the new Leica X Vario Type 107.
I'm here to tell you the APS-C is not a cropped or reduced sensor. It's just another form factor. Very mush less expensive to manufacture then a FX sensor. That's why cameras that use the APS-C sensor cost up to a 1/3 less than FX sensor cameras.
Camera makers love the FX sensor because they can charge a premium for them. Though lately that has been a problem.