eudroken, about the t8's you are on the right track.
if you had three 20 watt bulbs
one t12, one t8 one t5
all producing the SAME lumen output and all the same length.
The t5 would be about THREE times more intense at its surface.( 5/8" vs 1.5" diameter)
Most cfls are t4 or t5 size just wrapped in a spiral, they are pretty intense at their surface relative to old t12 flouro tubes. thats why they are good for growing but only very very close!
Once the distance increases only then does the lumen output from the bulb come into play. across a room for example a 1500 lumen t12 t8 or t5 produces the same light in the room.
if you had three 20 watt bulbs
one t12, one t8 one t5
all producing the SAME lumen output and all the same length.
The t5 would be about THREE times more intense at its surface.( 5/8" vs 1.5" diameter)
Most cfls are t4 or t5 size just wrapped in a spiral, they are pretty intense at their surface relative to old t12 flouro tubes. thats why they are good for growing but only very very close!
Once the distance increases only then does the lumen output from the bulb come into play. across a room for example a 1500 lumen t12 t8 or t5 produces the same light in the room.