[Kailash]

These are defiantly an improvement in terms of sharpness; it looks like you had better light conditions than the original post allowing faster shutter speeds. In these conditions it would be better to use a smaller aperture (larger number like f8 or f10) to allow you to capture more of the subject in focus.

Since you’re getting so close to sorting out your issues with sharpness you can start thinking about other aspects of wildlife photography. With wildlife its often ideal to try and get on the same level as your subject which will often mean getting down low especially for birds on water.

good luck

[BigDave]

With wide aperture lenses, keep in mind that the widest aperture will probably NOT be the aperture that will give the sharpest image, even at the point of focus. The general rule of thumb, the lens is sharpest 2 to 3 stops down from the widest aperture. So for a f1.8 lens, f3.5 to 4 will be about right. But with an f1.8 lens, the lens will have a range of a couple of full f stops that will give the sharpest images before diffraction starts (at about f11 or 16 and beyond), where sharpness starts to be negatively effected again. So you can play with the best aperture to give you the DoF you are shooting for and still get a REAL sharp image.

And the points about having NO DoF to work with is important. You are shooting moving objects and want them in focus? Luck will be as important as your equipment!