I was really happy till last week. During a conversation, someone told me that any zoom lens above the number of its lowest zoom in multiple of 10 will be a scrap. For example, 18-200mm lens is a scrap according to him 10 multiple of 18 is 180 but the highest number is 200 in this case and so lens do not perform at its best. I did some search for this but not convienced by this argument. If it is true, why 18-200 mm lens are so popular in the market. (my lens is 18-200).