I received the new replacement modeling light bulbs today and, as promised, I ran a test to see how they perform relative to the stock bulbs supplied with the Genesis kit.
Test setup was simple: Genesis 200 on a lightstand positioned 3' away from a tripod-mounted Minolta Flashmeter IV set to ambient light mode. ISO set on the meter was 200; shutter speed set to 1/8 second. The slow shutter speed was required in order to get a meter reading when the Genesis was set to minimum output (the modeling light is extremely dim at the "10" power setting).
So, here are my results:
To cut to the chase, it would appear that the new, low cost bulb performs just as well as the "stock" bulbs. The metered differences among the three bulbs tested are, in my estimation, hardly significant. Note that the output variation between the two original stock bulbs is greater than the variation between "Stock Bulb 2" and the new bargain bulb. Although not shown in the table, I also tested "Stock Bulb 1" in my other Genesis light and was pleased to see no more than a .1 stop variation between it and the other Genesis 200 at any power setting.
I think the real news here is just how non-linear the output of the Genesis lights is. What was true when I tested the flash output linearity a few months back, is equally true for this test of the "proportional" modeling light output. The modeling light output may in fact be proportional to the flash output in which case it's doing its assigned job well. It just needs to be remembered that neither the flash nor the modeling light output is linear over the indicated "10" to "60" power range.
One final point, the replacement bulbs are somewhat smaller than the originals.:
Dave F.
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