Tuesday, August 9, 2011

4W LED bulb from DX

I got my hands at the 4W LED bulb from DealExtreme.
I put it to a directional reading lamp that normally hosts a 60W incandescent and the result was not really satisfying.
While the reviews at DX (most of them apparently written by the seller) say the light output is the same as a 40W incandescent, this is simply not true. Unfortunately I don't have any 25W nor 40W bulbs to compare, but I don't doubt a 25W one would still outshine it.
With the LED bulb the lamp can really be only used for reading and nothing more, but it's good enough at that (if you're close enough). Another plus is that it fits well in the lamp - a fluorescent compact bulb would be unacceptable here and there's no heat and no risk of broken glass in case of an accident.

Below are pictures of a white wall taken with Canon A85 in manual mode, using the same white balance, aperture and exposure values. (The spot in the top right is a defect that developed in the past year or so, I just don't have the A590 at hand ATM)

As a ghetto scientific method of light output measurement I also took a look at the histograms that GIMP kindly provides. It looks like the LED bulb is very weak in the blue part of the spectrum and the median value 2.5x higher (likely even more as part of the red channel is burned out in the 60W one) for the incandescent supports my estimate that the light output is at best comparable to a 25W incandescent.


60W incancescent
4W histogram

60W histogram

1 comment:

  1. I would pretty much prefer an LED light specially for emergency vehicle lights because it's more efficient. It's guaranteed too that it doesn't consume much energy.