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Sunday, November 15, 2009

CFL Headlight Lighting Photos (ISO Comparison), 42°F

NOTE: All these pics are uploaded in full-size format, because shrinking them causes problems with the lighting comparisons due to high CCD noise from the low light levels. CTRL-Click or Middle-Click each one to open the original in a new tab in at least some browsers.

I found the automotive lamp lens I had in my junkboxes, and fit it into the styrofoam cup at what I could best determine by experimentation as the best focal point with the wide light source this lamp provides. For a point source, it would be around 2.5 inches in front of the source, but it seems to prefer around 1 inch or less from the tip of this light to get more of the light focused into a beam.

Since the walls of the cup are white, it still scatters a lot of light, but that's ok--I'd rather scatter it than absorb it and waste it. When I tried a black paper cylinder around the inside of the cup (past the lens) then it darkened the output by more than half, though it was more beamlike with it that way. Definitely prefer more light even if it is not a beam.

Last night it was pretty cold, about 42F at the bike when I took these pics, and it caused some fluctuations in brightness--the CFL was pulsing about half again it's usual brightness about once per second for about 10% duty cycle, if that. Took some effort to start it up, too; had to turn it on, let the tube warm up then turn it off and back on, a few times. Pack was fully charged but only reading 42.1V, probably due to the cold. Got noticeably brighter in the first couple of minutes, so I waited ten minutes before taking any pics.

I meant to do more, but the cold was numbing my fingers, and I could not operate the camera with gloves on, so I had to stop when I could no longer accurately push the buttons.

I took the pics using the manual mode of the camera, at ISO 80 (1.0 second exposure time, F/2.8) and ISO 1000 (0.77s exposure time, F/2.8). I'm not entirely sure what those mean in this camera (Sony DSC-W50), because the ISO1000 pics are noticeably brighter than the ISO80, even though the shutter time is shorter. All other settings it has available to me are set to manual; white balance is set to fluorescent as it has no "neutral" setting.

The ISO 80 pics are pretty blurry because I could not hold it still, and didn't use the tripod (forgot about it).

Anyway, I used two modes so you can have a comparison of different light/exposure levels relative to ISO numbers to gauge how bright this light actually is. I tried to capture other lights in the area in some of the pictures as well, for further comparison. I did not think to also include any of my own lights, but I should have included at least the 9-LED Harbor Freight flashlight I use as my helmet light; it's common so you could compare one to this lighting. I'll try to get more pics tonite of it.

12 feet Away Oncoming View with Dogs 9 feet from Headlight ISO80

12 Feet Away Oncoming View with Dogs 9 feet from Headlight ISO1000

Full Bike From Rear ISO80

Full Bike From Rear ISO1000

Full Bike Side View ISO1000

Full Bike Side View with Dogs 9 feet from Headlight ISO1000

Full Bike Side View with Dogs 9 feet from Headlight ISO80

Full Bike Side View with Dogs 9 feet from Headlight ISO1000

Rider View ISO1000 Darkness Reference

Rider View ISO1000

Rider View ISO1000

Rider View with Dogs 9 feet from Headlight ISO80

Rider View with Dogs 9 feet from Headlight ISO1000 AUTOMODE

Rider View with Dogs 9 feet from Headlight ISO1000

Rider View with Dogs 9 feet from Headlight ISO1000

Rider View with Dogs 9 feet from Headlight WITH FLASH


  1. Judging by the photo taken in automode it looks like the CFL is of the 'warm white' variety- do you think the colder bluish-white CFLs would have enough UV output to cause the bike's dayglo paint to fluoresce? How does the CFL appear in terms of color alongside halogen car lighting? Maybe a cold white CFL might stand out in the way HID lighted cars stand out from ones with halogen bulbs... I'm curious how drivers react to this brighter light compared to the previous CCFL headlight with less output but somewhat larger profile.

  2. Congratulations on post #200

  3. It was #200? I missed that. :-|

    This is indeed a warm-white version; almost yellowish, at 2300K (as marked on the bases). I didn't have a choice of types at the 59-cent sale. :-)

    A bluer one would certainly stand out more. If I had one I'd be curious to see how it does with the paint, etc.

    I have not noticed a difference to driver's reactions yet, but I have had a few pedestrian and cyclist reactions that are different; mostly stopping and staring, probably trying to figure out what the heck it is.

    I'd really like to make at least a taillight that shows the actual CFL bulb in there, just to really mess with people's heads.

    To that end, I have a plan and some parts gathered, to be posted soon....

  4. Someone has already copied the idea, in a more professional-looking DIY design:
    (Steve-O from Endless Sphere forums)


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