Shallow depth of field gives clear instructions to your eyes on where it wants them to be by creating a blur behind the subject.
By simply putting your F-stop down to the lowest number it will go or thereabouts (ie 4.5 depending on your lens, it can go a lot lower) it can have a shallow band of sharpness.
Funnily enough the lowest number is actually the largest aperture letting a lot of light in which tends to blur your photo. On the opposite end of the scale by putting your aperture theoretically to the highest number (smallest aperture) ie 25 or more this should give you the sharpest picture with more of your photo being in focus. Usually though somewhere in the middle is better depending on what you want sharpest.
I use a focal point of 11 up to 14 for landscape which is supposed to give you the best coverage over a larger area. For flowers, to have a bud stand out, shallow DOF is a good way of doing this.
So Ed has asked for a shallow depth of field (DOF) and so here is mine. I have posted this before.
For more shallow DOFs go to Ed’s Sunday Stills here.