This may not be the correct forum to post but it does concern a Problem I have recently whist experimenting with small apertures.
The use of very small apertures has highlighted the annoyance of dust/dirt in my camera light path.
I can see no dust particles in or on my Canon 17-85mm Zoom lens elements. The lens was originally sent to Canon for cleaning shortly after purchasing it ,due to particles of dust visible on its front inside element. I mention this because I now think the lens is ok.
Can any Pixalo members suggest the likely cause of the problems shown in the F32 picture. Clearly there is dust/dirt somwhere in the system and the extreem depth of field offered at F32 highlights this. At F5.6 the problem is much less noticeable.
Many Regards Brian