I've just got around to printing up a macro shot and I'm a little disappointed as it is not as sharp as it ought to be.

Equipment - Mamiya C330 with 80mm lens
Magnification ~75%
Exposure 2s @ f:22
film Ilford delta 400, dev in X-tol 1:1

Naturally the set up was properly supported on a good tripod.

My question is - by using the small f:22 stop to increase depth of field did I inadvertently introduce a noticeable diffraction effect sufficient to to take the edge of the sharpness? Would the image have been sharper had I used f:8?

Thanks for any feedback.