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I purchased this LUX meter a while back and never used it except for pinhole images. Today I decided to get more use from it. A quick check online showed me the same thing. I did not find a place that directly related the LUX level to an exposure time or an aperture opening or ASA. I feel exposure time is a better method than one that uses aperture openings as aperture changes can make a huge difference in depth of field.
Taking five different sources, I made my own little chart – it is below. Up front, make no mistake, I use this and it works for me. It may not work for you. A level of knowledge is assumed in the use of this chart. I will not be held responsible for any mishaps that YOU may have if YOU attempt to use my chart knowing that it may not work for YOU. Also, see the disclaimer elsewhere on my blog. Don’t you just LOVE lawyers?
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This chart is based on using a 100,000 LUX meter for photography
Chart Constants are ASA 100 and f 2.8
ASA Steps– 100 – 200 – 400 – 800 – 1600 – 3200 – 6400
Full f Full Stops 1.4 – 2 – 2.8 – 4 – 5.6 – 8 – 11 – 16 – 22 – 32 – 45 – 64
LUX TIME EV OBSERVATION
5 4.0 1 Distant View of Lighted Skyline
10 2.0 2 Total Eclipse of Moon
20 1.0 3 Fireworks
40 1/2 4 Candle. Christmas/Street Lights
80 1/4 5 Average Night Home Interior. Auditorium
160 1/8 6 Bright Night Home Interior. Amusement Parks
320 1/15 7 Bright Night Streets. Indoor Sports, Shows
640 1/30 8 Bright Flourescent Interiors. Times Sq Night
1300 1/60 9 Landscapes, Skylines 10m after Sunset. Neon Lights
2600 1/125 10 Landscapes, Skylines Immediately After Sunset
5100 1/250 11 Sunsets. Deep Shade
10000 1/500 12 Open Shade. Heavy Overcast
20000 1/1000 13 Cloudy Bright
41000 1/2000 14 Weak, Hazy Sun
82000 1/4000 15 Bright Sun
100000 1/8000 16 Bright White Sand, Snow
NOTE: Most cheap LUX meters as sold for <$50 on e*ay need to have some
manner of shade to prevent light from sides, top and bottom affecting the
actual light reflected from the subject.
NOTE: To adjust the ASA – IE: If your camera is set for ASA 800, that is three
steps above ASA 100. Simply move numerically UP three LUX levels. IE: 80 to
160 to 320 to 640 and use that line.
NOTE: To adjust the f stop – IE: If your camera is set for f11, that is four steps
below f2.8. Simply move numerically DOWN four LUX levels. IE: 1300 to 640
to 320 to 160 to 80 and use that line.
NOTE: If your camera is set differently for both f stop and ASA, BOTH
adjustments must be made.
NOTE: If the LUX value falls between given values (and it most probably be the case)
remember:
Spock: Ah. Then, I will try to make the best guess I can.
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These meters tend to work as averaging meters- taking into account everything in front of the frosted dome. I contact cemented a filter ring in place. Now I can put various lens shades on the sensor. As you can see in the photographs, the shade cut out most of the direct light coming from the overhead light. DUH! Warning >> cementing a filter ring on your meter will in all probability void any warrantee covering the meter.
