Below are some tables compiled from data about various lamps so that you can compare and contrast different lamps yourself. Things to remember! Different sources of light have different light spectrums some better for plant growth and some not so good such as incandescent bulbs. Plant growth is heavily influenced by the amount and colour of the available light. Blue light at about 450nm favours root growth and intense photosynthesis. Red colours at 600 to 700nm stimulate rapid stem growth, intense flowing and chlorophyll production.
An interesting note about PAR watts and lumens for MH and HPS lamps is that the correlation between the two is over 97%. Meaning that for HPS and MH lights (remember the very restricted sample used here) on average there is less than 3% variance when estimating PAR watts from lumens. But remember that is an average and some lamps the difference may be much more.
Lamp Efficiency In PAR WATTS