Macro Focus Question

Today I was practicing shooting some dead wildflowers against a backdrop of a moving stream. My objective was to keep the wildflowers in crisp focus & allowing the moving water to blur the background creating a fluid negative space. I was using a Canon 400d with a Canon 100mm f/2.8 macro lens. Lens-to-subject distance was about 12" - 18". I was focusing manually with mirror lockup on a tripod.

Even at f/22 I was unable to capture the subject is crisp focus. Was this because the lens-to-subject distance was too short? I would really appreciate some guidance here. Thank you for your help.

None of it was in focus, or just very little in focus? Even at f22, at that distance the depth of focus is still only a few mm. I know you want to blur the water, but first try a faster shutter speed so you can see how much of a factor it may or may not be. If there's any sort of breeze...well, flowers move and macro distances will magnify this issue. The other issue may be insufficient lighting. If you're at f22 then you need a flash, or a really bright day, and/or up the ISO.

I assume the subject did appear to be in sharp focus in the viewfinder ?
I'd guess your shutter speed was likely to be too low as commented above, with the subject moving slightly in any breeze.
Brian V.

Thanks for getting me to look at the obvious. The issue might have certainly been an never-so-slight breeze. Coupling that with a slower shutter speed under overcast skies, this is all starting to become embarrassingly obvious.

Focusing should not have been an issue. When manually focusing, I did get the tell-tale "beep" & the flashing focus point.

Another thought: part of the blurring might have been due to diffraction at small apertures like f/22.

But me thinks that the culprit was Mr. Wind. Thank again.