If we work with a known reflectance, say an 18% grey card, and read its EV number under a certain illumnation, we should be able to convert this illumination to footcandles, no?

I'm pretty sure that f2.8/100ASA/1/60th sec requires 100 fc. According to my meter, this is EV 9. So if I read EV 8 somewhere, I'd be reading 50 fc, right? EV 7 would be 25 fc, EV 6 12.5 fc, etc. Am I away off base here?

I know this probably isn't the right forum, but you guys seem to know stuff.

Thanks for steering me right or wrong.

-- Peter McLennan (peter@vfs.com), August 18, 2001

Answers

Peter:

According to my 30 year old Gossen Lunasix-3 (European version of a Gossen Luna-Pro), you are correct in your concept. Years ago we could find the information in the owners manuals, but now it is considered too technical for our more intelligent minds. My meter shows EV9 to be 130 foot candles or 1400 lux. I hope this helps you.

Mark J.

-- Mark A. Johnson (logic@gci.net), September 30, 2001.