Can anyone let me know what I've just bought... I purchased this lens yesterday off the internet: Tamron AF 28-200mm f/3.8-5.6 LD Aspherical (IF) Super. I don't know what I did. I heard this was a good lens somewhere but did I make a wrong choice for a beginner? I don't know if it's fast or slow. I don't even know what LD Aspherical (IF) Super means. I thought I also saw somewhere it is a macro or has a macro function. But with that aperture? See! I don't know ANYTHING about this equipment or how to even use the words in the right context. Oh what have I done?!! Can anyone tell me what this lens is all about?