All lamps are new and fitted with standard bulbs. The same test voltage was used for each test. For an explanation of how to understand the diagrams on these pages, which will open in a new tab or window for you, please click here.

Halogen 5¾” 2C1 or H5006 sealed beam (a particularly well-made Koito unit no longer manufactured), on low beam setting: Reasonably intense and well-placed
low beam hot spot, but narrow beam width, almost no light on the road surface in near and midrange, and lots of upward light that causes backglare in bad weather.

And the same H5006 (2C1) sealed-beam headlamp on high beam setting: Same beam pattern, shifted slightly upward-leftward:

Cibie 5¾” round convex-face H4 lamp (most efficient of its type) on low beam setting: Wider beam with better road surface and RH shoulder illumination, but unacceptably low hot spot intensity with excessive offset to the right:

And the same Cibie 5¾” round convex-face H4 lamp on high beam setting: More intense straight ahead of the car:

Hella BiFocal 5¾” round flat-face H1 low beam: Extremely intense, large high intensity zone, well located close to straight ahead. Very wide
beam width. Even lighting of the road surface. Enough light for overhead road signs, but not so much as to cause backglare. No stray light, careful control of glare light. Over double the luminous flux (light within the beam) of the sealed beam, and 55% more than the H4: