relationship between EV and Lux

greenspun.com : LUSENET : Leica Photography : One Thread

I have read Mr. Puts article of "The exposure meter and its calibration" at his web site. The first part of the article mentioned that EV 10 has a brightness level of 2600 lux. EV 9 is 1300 lux etc. However, the rear part of the article said EV 15 equals a lux value of 150,000 and EV 14 equals 75000 lux. Using EV 10 = 2600 lux to count up, EV 14 will equal 41600. Using EV 14 = 75000 lux to count down, EV 10 will equal 4688 lux. So what excactly is EV 10 equal? I have sent a email to Mr. Puts to enlighten my query but no response is received so far. Can knowledgeable friends here help me out? Taking the chance, may I wish everyone here a prosperous Year 2002 and beyond. Regards

-- tom tong (tom.tong@ckh.com.hk), December 31, 2001

Answers

Tom:

According to the back of my Gossen Lunasix-3 meter which I purchased in 1972, I can pass on the following information. The back of the meter has a scale on it which corresponds to the front of the meter. I can set the meter to read the scale the same as EV and I get the following information:

EV1=.017 lux EV2=.035 lux and so forth.

EV10=88 lux EV11=175 lux.

EV14=1400 lux EV15=2800 lux.

EV22=350000 lux.

I also read in my 1974 Morgan & Morgan Photo Lab Index and a quick read didn't do anything to clear things up in my mind. If you have a fax and can e-mail me privately, I can fax you the pages from the Photo Lab Index. :) ??

-- M. A. Johnson (logic@gci.net), December 31, 2001.


M.A.:

Is your reading based on ASA 100 or there should have no bearing on ASA at all? Your figures seem low as I check with my Gossen Sixtomat, the EV in my office is 7 and according to your figure, it should equal to ll lux - my understanding that normal office lighting should be around 300 lux. Regards,

-- tom tong (tom.tong@ckh.com.hk), December 31, 2001.


Footcandles times 11 (approx.) equal lux...EV values are referenced to ASA. When measuring Fc or lux, an intergrating sphere is necessary.

-- Tony K. (tony_k_@hotmail.com), December 31, 2001.

Moderation questions? read the FAQ