Octarine said:I don't think it's any effort for the lens .. haven't seen any lens sweating in the efforts of projecting an image circle that was actually not necessary in that size
Now that's puzzling, wouldn't it requires extra effort to fine tune and calibrate the lens or take extra effort for better design to cover those edges of the lens if these lens are meant for FF bodies? Certainly it would be no sweat to project light rays, but it will need more effort to get the rays right with least colour aberration and so forth.
Octarine said:Have a look at the topic 'sweet spot of FX lenses', it's highlighted in many reviews. Due to the fact that the DX sensors cuts off the far corners of the image circle it also cuts off the most problematic areas for corner sharpness and vignetting. Something that becomes visible (again) when using DX lenses.
The promotion happens everywhere when Canon & Co showcase lenses to consumers who mostly use DX cameras. All the promotion material and Lens Books never state 'Lens designed for Full Frame Body' or 'Only to be used with FX body' but rather address certain shooting requirements and other things which make it obvious to the 'ambitious amateur' and 'photographic enthusiast' that the lens with the red / golden / green / whatever ring is the best choice. In contrast, the DX lenses are used as kit lenses (ok, not all) which serve to complete the starter package of DX cameras at a lower price level.
yes, I am aware of the sweet spot theory. Though it will be a sacrificial of FOV when using FX lens on DX bodies. Okay lower pricing for DX lens make sense