[arleneg]

First, here's info on how to measure light intensity with a 35mm camera (according to the link Mike provided in his first post on this thread):

You can also use a 35 mm camera to measure light. Here is how to do it:
• Set the camera at 25 ASA.
• Set the shutter speed at 1/60 of a second.
• Place a white sheet of paper where the leaves of the plants would be.
• Focus on the white sheet of paper from a distance of 1 foot.
• Make a note of the f/stop shown in the viewfinder.

Here are the approximate foot candles corresponding to various f/stops:
f/2 = 100 fc
f/2.8 = 200 fc
f/4 = 375 fc
f/5.6 = 750 fc
f/8 = 1,500 fc
f/11 = 2,800 fc
f/16 = 5,000 fc.

Remember the maximum light should be at noon on a bright summer day.

Using the following settings on my SLR camera (equivalent to a 35mm film camera),

100 ISO (the lowest on my SLR digital camera)
1/60 of a second shutter speed

here are my results from measuring the fluorescents lights in my shelf unit.

Bottom shelf
• Humidity tray surface (2 1/2" from shelf surface) = f/6.3 - 7.1
• 14" from fluorescent light surface = f/9 - 10
• 1" to 3" from light surface = f/16-18

Top shelf
• Humidity tray surface (2 1/2" from shelf surface) = f/8 - 9
• 14" from fluorescent light surface = f/10 - 11
• 1" to 3" from light surface = f/18 - 20