Robert your close up images are very blurry. Are you using the setting on your camera that looks like a small tulip. This in most cameras is the close up setting. Take the photo from c. 12" away and then crop the images before you resize and you ought to get better results.
Sometimes the crop and resize approach works well with normal images as well - whatever takes a sharp photo. You can "Blow up" a sharp image quite a bit and still get a clear result.
Ross