I have one Chinese made lens, a 25mm f1.8 7Artisans. What drives me crazy (a short trip) is that the focusing scale on the lens is completely wrong. Not slightly off but so far off that focusing at 2 feet the scale shows 5 ft.
It appears that the focusing scale from a different lens was accidentally printed on this lens. Apparently all of this model have the same wild focusing scale.
For an old dog like myself, who is used to surreptitiously prefocusing by scale when I don’t want to draw attention to myself. This is enough to almost ruin the experience with this lens.
Edit; Really should add, the foregoing complaint is an operational issue. The image quality is ok, especially since mine was a eBay BIN for $50, LNIB. The IQ is slightly better than my adapted Pen F 25mm f4 Zuiko, which was made in 1964. I did shim the Pen F to 4:3 adapter. All these mount adapters from China seem to be too short, usually between .004 to .006 inch. I guess the manufacturers want to be sure you can reach infinity focus.