In an earlier article I had compared a cheap minolta lens, the 4/35-70mm, on A900 full frame, with the Zeiss 16-35mm, also on A900, but using simulated (cropped) APS-C mode.

Here I will directly compare ...

1) the A900 (24MP Full Frame), using the "cheapest" and "worst" Minolta AF lens, the late 3.5-5.6/28-100mm kit lens, at a focal length of 35mm
2) the A700 (12MP APS-C, re-sized to 24MP), using the Zeiss ZA 2.8/16-35mm, at a focal length of 24mm

All images shown here are 100% crops from the JPGs directly out of the A900 and A700, respectively. To get the same image, the A900 was used with f=35mm focal length, and the A700 was used with f=24mm. To get the same output size, the A700 image were re-sized to 6048 x 4032 px. Overall, we come to the same conclusions as last time - one gets a better detail resolution using the A900 24MP sensor and a cheap plastic lens than using the APS-C A700 with the best Zeiss lenses available.

Cameras: Sony Alpha 700 and Alpha 900, respectively. ISO 100, DRO level 4, AE-2/3, contrast +2, sharpening +2, JPG extrafine
Lenses: Minolta AF 3.5-5.6/28-100mm kit lens @ f=35mm (using the A900 24MP Full Frame body), Zeiss ZA 2.8/16-35mm @ 24mm (using the A700)
Tripod: Manfrotto MTL 8351B carbon with Manfrotto 410C three-way-head

	Both lenses wide open, both lenses certainly at their "sweetest spot": The "A900 & plastic kit lens" combo has clearly the better detail resolution than the more expensive "A700 & Zeiss 16-35mm"
	When both lenses are stopped down to f5.6, the advantage for the Full Frame system becomes even more visible. The Zeiss at the APS-C sensor doesn't improve much when stopping down (the A700 sensor is obviously the limiting factor); the kit lens however improves when going from f4 to f5.6.
	Corners, both taken at f4 - this is the worst case scenarion for the plastic kit lens: wide open, and in its extreme corners, while the Zeiss is stopped down and (here at the A700) uses only the "sweet spot" of the APS-C. Yet the "A900 & plastic kit lens" results in a more detailed image. Note that the Zeiss even on APC-S suffers from some field curvature, resulting in "unsharp" corners
	At f8, the corner resolution of the "A700 & Zeiss" combo has clearly improved, while (surprisingly) the A900 & plastic kit lens didn't get much better. The A900 image has more details now, but some pronounced CA become visible when stopping down.