Hey there.. when using a camra's macro mode the slightest shake of the camera will cause the photos to come out blurry. for this reason you should use a tri-pod and the camera's self timer function to take the photo.
most store that carry digital cameras, also tend to carry small 6 to 8 inch tabletop tri-pods at around $10
Also the closer you are to your subject the smaller the area of the frame that is actually in focus. for instance if you up real close taking a photo of the front of say a tank turrent... the sides and rear areas and the forward hull might not be in focus in the photo due to the fact that you focused in close on the turrent..
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