Hello, I've acquired a Colorstar 3000 analyser with b/w sensor (the 301). It has the 54mm diffuser cap, not the 10mm spotmetering cap. The producer is out of business. My question to anyone using the Colorstar (or similar) for B/W work Would it be much of a problem using it without a cap at all for spot-metering ? Common sense hints two possible problems: -without a cap light from the side could influence the metering - the naked cell is vulnerable (dust,etc;..) What do expert users of this device have to say ?