hi together, recently my last 300w opal bulb gave w.o. i wanted to purchase a new one, just to learn that they are not produced anymore- in my area (austria) they just sell the smaller 150 or 250 W bulbs- they are approx. 5cm in diameter, while the old bulb was maybe twice as big. now my problem is that with the smaller bulb i get vignetting when enlarging 4x5inch... is there a way around this? does anybody know where to get the big bulbs?