That's a good run down by CLS and the quoted section above really sums up the two main points that I was thinking too, it's also something that I remember having to get my head around when I first began using a DSLR.
The (very) basic idea is that lens / camera combos have a "sweet spot" in terms of what aperture will provide the best sharpness. It is generally somewhere between f/8 to f/11 with a bit of variation either side. Any narrower (i.e. higher f/ number) and lenses start to be effected by diffraction with results in loss of sharpness.
For a scene like yours I think f/11 at 29mm would be more that sufficient to provide a deep enough depth of field to keep your scene in focus. There's a great website called Depth of Field Master [ http://www.dofmaster.com/ ] where you can put in your shooting parameters and it will calculate the depth of field. There's an app for smartphones available as well.
I threw your settings into it and assumed that you were 10m from the duck and below is what is spat out:
So it's telling you that the scene will be in focus from 2.82m to infinity, which would cover everything in your picture.
The other side of the story is the shutter speed. If you don't have a steady have then you may suffer from blur as a result of camera shake at 1/40 secs. By reducing your aperture setting to f/11 you will have a much faster shutter speed which will in turn help to eliminate camera shake.
Hope this helps a bit.
Ben.





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