FOOT-CANDLES READING: Using Exposure Meter

Orchid Doctor

by Robert M. [Bert] Hamilton (Compiler)

Originally published in The Orchid Doctor in 1980 and 1988

Posted by Sys Admin over 7 years ago.

Article Blog   Article Index
Set ASA at 10 and exposure at 1/100 second; hold the meter pointing at the center of clean white surface as closely as the smallest diameter of the surface(such as paper) casting no shadow and read: f/3.5 is 400fc.; f/4 is 500fc.; f/4.5 is 650fc; f/5 is 800fc; f/5.6 is l,000fc; f6.3 is l,300fc.; f/7 is l,600fc.; f/8 is 2,000fc; f/9 is 2,400; f/11 is 4,000fc. ; f/12.7 is 5,200fc; f/16 is 6,400fc. A62-105+; A69-1003; A75-680
Share on Social Media:  
Log in to Add a Comment

More The Orchid Doctor Articles under the Heading Foot-candles

Foot-candles Comments
FOOT-CANDLES: Conversion Table Using a Weston light metre and a sheet of white matte cardboard, take exposure readings and rate them with foot-candles of light 16(6400), 15(3200), 14(1600), 13(800), 12(400), 11(200) etc. down to 4(1.6); the average for orchids is 14(1600); bright daylight with overhead sun is 10,000fc (England). OR-22 0
FOOT-CANDLES: Fc Rating Meaning One foot-candle equals the light emitted by one candle one foot away; expressed ratings are measured at noon Standard Time on a clear day; the maximum amount would be recorded around June 21 and the minimum December 21 in North America; a June 21 reading of 3950 fc. means a range of 2000 0 4000 for the year. A85-332 0
FOOT-CANDLES: Interpretation of the Meaning The recommended foot-candles of light for a species means the direct or incident light. A64-975 0
FOOT-CANDLES: Light Intensity Required by Plants Cattleyas:2500-3500; dendrobiums: 1500-2500; miltonias: 800-1200; odontoglossums:800-1000; phalaenopsis: 800-1200. 0R81-112 0
FOOT-CANDLES: Meaning The amount of light emitted by a burning candle one foot away; 500fc. is about enough to read a newspaper; a clear day in June (in Maine) would be 12,000. A86-814 0
FOOT-CANDLES: Minimum Amount Required to Affect Flowering This has not been determined; it is generally assumed that more than two fc. of light intensity is required to delay flower initiation by orchids; most commercial growers use lOfc. or more. A67-45 0
FOOT-CANDLES: Optimums For cattleyas the range is 2400 to 3600, for phalaenopsis it is 1500 to 1800. A86-815 0
FOOT-CANDLES: Outdoors, in Alberta During the summer there are about ll,000fc.; during winter between 4,500 and 6,000fc. A60-770 0
FOOT-CANDLES READING: By Means of Photographic Light Meter (weston Master) Read the light reflected from the surface of white blotting or type-writing paper without light from any other source; multiply the meter reading by four. A67-415; A74-34; Sekonic meter. A68-431 0
FOOT-CANDLES READING: Gro-lux Fluorescent Tubes Multiply foot-candles by 2.18 for correct fc. reading under Gro-Lux when using photo-exposure meter readings under normal light. OD70-242 0
FOOT-CANDLES READING: Using a Built-in Light Meter in a Camera Set the speed dial at ASA25 and the shutter speed at 1/60; aim camera at center of sheet of paper eight inches by eleven, eight inches distant; the lens opening (f-stop) is adjusted until the meter shows correct exposure; if lens opening is f/2 illumination is about 40fc.; f2.8 is 75fc.; f/4 is 150fc.; f5/6 is 300fc; f/8 is 600fc; f/11 is l,200fc.; f/16 is 2,400fc.; all figures approximate. A78-408 0
FOOT-CANDLES READING: Using Photographic Equipment Use the meter on the camera; point latter at center of sizeable white surface without casting a shadow; set ASA at 10.3 and the shutter at 1/100 second and read: f/3.4 is 400fc.; f/4 is 500fc.; f4.5 is 650fc.; f/5 is 800fc f/5.6 l,OOOfc.; f/6.3 is l,300fc. ; f/8 is 2,000 fc; f/10 is 3,200fc; f/11 is 4,000fc; fl2.7 is 5,200fc; f/16 is 6,400fc; A65-244; A74-896; OR76-360 0
FOOT-CANDLES READING: With Photographic Light Meter Meters can be bought for reading foot-candles; with a Weston photographic meter convert to fc. by measuring light reflected from a piece of white matte paper and multiply the light value by four. A73-1081 0
FOOT-CANDLES: Requirements A sodium vapor lamp illuminated all night 100ft. away from cymbidiums in a greenhouse may not affect their flowering because they are temperature-responders; but plants requiring short days will not flower. A86-815 0
FOOT-CANDLES: Requirements for Main Types Cattleyas/laelias 3,000-3,500; cymbidiums 3,000; dendrobiums 3,000-3,500; odontoglossums 2,000+; oncidiums 2,500+; paphiopedilums 800-1,300; phalaenopsis 1,500-2,000; vandas and allied 3,500-4,000. OR76-360In summer: cattleyas 2,400-3,600; cymbidiums full sun; phalaenopsis 1,200-1,500; in winter: no shade generally for cattleyas and cymbidiums; if winters are partly sunny some shade is required by phalaenopsis and paphiopedilums. A61-734; OD73-198 0
FOOT-CANDLES: Requirements for Some Types Epidendrums like 3,600, and some will stand full sun; laelias like 2,400 to 3,600. A61-982 0

New Topics

  1. David George asked question recently purchased orchid shows unstoppable roots in category General Discussion
  2. katherine mott asked question shorter stem with less vigorous blooms in category Phalaenopsis
  3. Glenda Ratliff started topic need info on yellow bird in category General Discussion
  4. Paula Milano asked question Looking to join an orchid club. in category General Discussion
  5. Jeanne Uzar Hudson asked question Meetings for Advanced Growers in category General Discussion
Ask a Question

Start a Topic

New Comments

  1. Carol Holdren commented on topic "recently purchased orchid shows unstoppable roots " by David George
  2. Michael Makio commented on orchid V. Beatrice Makio
  3. Carol Holdren commented on topic "shorter stem with less vigorous blooms" by katherine mott
  4. Carol Holdren commented on topic "need info on yellow bird" by Glenda Ratliff
  5. Carol Holdren commented on topic "Looking to join an orchid club." by Paula Milano
  6. Jeanne Uzar Hudson commented on topic "Repotting Large Cattleyas" by Jeanne Uzar Hudson
  7. Jeanne Uzar Hudson commented on member plant Paph. malipoense by Jeanne Uzar Hudson
  8. William Gorski commented on topic "how difficult is it growing from seed" by kevan gregory
  9. Carol Holdren commented on topic "Information " by Carmen Britton
  10. Carol Holdren commented on member plant C. lueddemanniana var. Coerulea, Venosa by Paulo Fiuza
  11. Jeanne Uzar Hudson commented on topic "Banrot 40WP" by Therese Stecher
  12. Maria Lucia Prieto Real commented on orchid Rlc. Village Chief Armani
  13. Mariana Chacon commented on orchid Gom. Jiaho Queen
  14. Roberto Lizama commented on member plant Max. dillonii by Roberto Lizama
  15. Nancy Speedy commented on scheduled event "2024 Orchid show Martin County "Ocean of Orchids"" by Martin County Orchid Society
  16. Jeanne Uzar Hudson commented on member plant Paph. Fanaticum by Jeanne Uzar Hudson
  17. R .Benson commented on member plant Den. Tianmu Green Elf 'Sweetheart' by R .Benson
  18. Alice Walker commented on article "Oeniella polystachys" by Tom Kuligowski
  19. Kathryn Kersey commented on scheduled event "Boca Raton Orchid Society Show & Sale" by Boca Raton Orchid Society
  20. BJ Lough commented on member plant Asctm. miniatum by BJ Lough