When the Wrong Lens Hood is Used for the Same Lens..

Then vignetting or even dark corners will happen, for the case of the same Q 02 lens that is used on a Q/Q10 versus a Q7, see the following test:

http://bbs.kakaku.com/bbs/K0000264454/SortID=16353126/?Reload=%8C%9F%8D%F5
(in Japanese, Google translation to English Here.)

So, the new flower-shaped lens hood must be purchased separately for the old lens owners, otherwise the old lens hood cannot be used, since it is incompatible.

It seems that Pentax had no good planning in changing the sensor size, so just causing this problem.

Btw, according to the test results, the dark corners are even larger in area when the automatic lens correction is turned off. Do note also the serious barrel distortion of the 02 lens that actually produced, which is terrible:



When it is corrected, it looks somehow better, see and compare:



So, nowadays, the trend of those camera and lens manufacturers are giving us junk lenses, and then images are corrected by software. Of course, there is no free lunch after all, some IQ must be lost and the correction would never be perfect.