focusing the blitz

[hubbytuby]

I just made a light very similair to Queenslanders, but i noticed that no matter which way I screw to focus, I can never achieve a tight beam with the osram 64663 bulb.

 

[BVH]

Is the filament of the new bulb in the same or close to the same relative position as the old bulb filament (relative to the metal nose of the light base)? You'd have to be off by 1/4" or more to not be able to make up for it by turning the reflector.

I don't know the filament size of the new bulb. If it's significantly larger, you won't get as tight a beam/hotspot as with the old bulb. But it shouldn't be that much of a difference.

 

[hubbytuby]

your right about the new bulb it is wider so i does not recess into the mount as far. So I carefully grinded it down to the point were its at the exact same position as orginal bulb. I still am not able to get that really tight hot spot. The new bulb puts out an oval beam with average tight spot. Its not bad but, there is not a significant difference in throw.

 

[BVH]

I'm not familiar with the new bulb. If the filament is significantly larger and possibly oriented in a different direction, you will not get as tight a beam. The larger the light source (actual filament), the larger the beam and hotspot.