Light Meters for Dummies

[WaterWitchin]

Oooooo!!! I really like the installers of spy cameras idea!! And much more exciting than algae enthusiasts!

[Orchidtinkerer]

Seems fairly straightforward to me. The dial to the left will always display the true footcandle measurement (x1 or 100%)
the next dial will display the footcandle value divided by 10 (or 10%)
the next dial will display the footcandle value divided by 100 (or 1%)
The reason you have dial 2 and 3 is I presume that the display cannot show more than 1000 footcandles so you need to flip the switch to the second or third position for high values like 1000-5000 so it can show 100-500 or 10-50 which is 10% or 1% respectively, otherwise you could just leave it on position 1 all the time. It is only a matter of the display not having enugh numbers so once you understand all the dial does is drop a 0 at the end then you have it figured out.

edit: in your second example the footcandle you were reading was 1063. On the first dial it could not display this so it shows 1. I can see where that would become a bit confusing. I suppose the safest is to leave it on dial 3 and always multiply the displayed value by 100.

[WaterWitchin]

Originally Posted by Orchidtinkerer

Seems fairly straightforward to me. The dial to the left will always display the true footcandle measurement (x1 or 100%)
the next dial will display the footcandle value divided by 10 (or 10%)
the next dial will display the footcandle value divided by 100 (or 1%)
The reason you have dial 2 and 3 is I presume that the display cannot show more than 1000 footcandles so you need to flip the switch to the second or third position for high values like 1000-5000 so it can show 100-500 or 10-50 which is 10% or 1% respectively, otherwise you could just leave it on position 1 all the time. It is only a matter of the display not having enugh numbers so once you understand all the dial does is drop a 0 at the end then you have it figured out.

edit: in your second example the footcandle you were reading was 1063. On the first dial it could not display this so it shows 1. I can see where that would become a bit confusing. I suppose the safest is to leave it on dial 3 and always multiply the displayed value by 100.

Yep, that's what I decided to do. If I'm not getting at least 1000 foot candles, it's time to adjust a light or move closer to a window! A Light Meter For Dummies would be great! One button, displayed without adding or subtracting zeros. For those who just want simple.

[PaphMadMan]

The 0-199 fc range may not be significant for orchids, but is for the limit for low light house plants. Below 100 won't really sustain much of anything, but many are fine at 200 long term. 100 fc is also significant in terms of indoor lighting for human eyes. Sight tasks like reading, playing darts or safely chopping with a sharp knife in the kitchen become more difficult below 100 fc. Laboratory benches are usually recommended to receive 100 fc or more.

[Clawhammer]

I find a light meter useful in two ways

1> To gauge relative light output between two fixtures
2> To monitor degradation of the brightness of a particular fixture over time.