Got a qns to ask here... ive been using a sigma 70-300mm APO MArco Zoom lens and whenever i use at maximum 300mm on tele shots, the color is kinda off... is not underexposed but white doesnt seem white, more like a tad of yellow... but when taken at marco level or at 70mm, the photo seems fine. cant post a pic here yet to further explain but one thing to add... the tele lens got a bit of fungus... not jialt case, more like specks... so cld it be this???