>>4271369>FF lenses can be less sharpThe image circle is 4x larger.
>CAN be less sharpYes, can, but usually aren't. For instance the sony 40mm f2.5 G is still visibly sharper when cropped in than the overpriced and shit olympus 20mm f1.4 pro except on the edges under f4. Then look at the sony 20mm f1.8, that's on the high end of much size and glass that needs to be included to gather light for an image that's 4x larger while maintaining, if not gaining, sharpness.
Why would FF need "more sharpness than it needs"? Because system mtf is an average of everything, theere is no hard limiting factor anywhere in it. Your lens cant be too sharp for your camera. A lot of people use FF lenses on M43 and find they are normally sharp and sharper compared to native lenses.
Panasonic's real-mm 100-400 f4-6.3 is priced like a 100-400 f4-6.3. I'd call that a ripoff, because FF ones are f5.6, and M43 loses light so even glass for it should be discounted, but I imagine the manufacturing costs of allowing vignetting out 3/4s of the image and being a bit slower than the usual FF f4-5.6 are offset by the manufacturing costs of ensuring a little more sharpness or better QC because panasonic's accompanying release, the g9ii, is equivalent to a 2x crop of a 100mp FF, and it does seem to be an unusually sharp lens. Probably sony GM tier. Go panasonic! No wonder they didn't go out of the camera business.
Olympus on the other hand is a scam brand. Their 150-400 f4 is priced like a 300-800 f4. But it's not. It's a 150-400 f4, that when cropped 2x, approximates the results of a 300-800 f8. Canon has such a lens, but it's wider, and faster on the wide end... and costs 1/3 as much. A typical release from the company that had to leave the camera business because THEY COMMIT FRAUD.
