Componons are sharpest at 5.6 and 8. The data sheet that came with my 50 mm, 2.8, said between 5.6 and 8 was optimum. At smaller apertures they begin to be less sharp. at wider apertures they can get soft out at the corners. So your lens should function perfectly well. If your exposures become to short you can use a lower wattage bulb, or put some filtration in the filter drawer. I've used frosted mylar, which has a nice soft effect. But a neutral density filter would be best - 0.6 ND being two stops less light.