_____________________________________________________ Issues with film flatness across the film gate have been reported across Zero Image cameras, particularly at and above 6x9 and especially 6x12. The flatness mechanism inside is rather rudimentary. And if the format slats are not fully seated, but ajar, that might have a bearing on softness. But I question whether film flatness is this culprit if you are using the 6x6. You can use more than one operating aperture besides the common f22: mine is f16, f19 and f22, set to the 6x6 format — the most common format in my own work. Twenty minutes is too long to loiter. Newbies to pinhole often get antsy about these long exposure times. I detest them so keep them low. Whenever possible, I keep mine to between 8 and 20 minutes, tops. I am not the type to sit cross-legged in the dirt singing Kumbuya while a pinhole counts down its hour-long exposure!