You will not be disappointed with your 24mm. I really liked mine until murphy had his way with it. You should have some money left over for film too. The weight of the extension tubes will not be a bother since you will not have them on all the time. When you buy them make sure they mount and work on the camera. In other words buy from a reputable source. I still have a set that are not for nikon mount no matter what the A***oles at cambridge camera said after I sent them back to them for the third time, even the box said Pentax.