It shouldn't be necessary to use a camera to find out the result. All you should need to do would be to use your eye directly. But the pupil of the eye is only a couple of mm wide so you would not see anything but a small portion of any pattern. It is easy enough to see some diffraction patterns directly, though. LEDs on cars can be seen through net curtains and other regular woven fabrics and they appear as fringes. However, the diffracting structure is very wide so the eye must be seeing different bits of the pattern, caused by different bits of the fabric weave. You are not looking at just a single hole / pair of slits etc. in that case.