Sealed-Beam ??

In order to have a spot beam does the glass always have to be clear or can it have some texture to it?

When the beam is stated as 5 degrees and you want to figure the width of the spot at 300ft can ya just (5/45) X 300 = 33ft to the right&left and say the spot would be 66ft wide at 300ft?

Thanks for any help.

I assume you mean the reflector when you say "glass", as it is usually only optional diffuser lenses that are opaque. It depends completely on how textured the reflector is, however an average OP (orange peel) reflector is fully capable of producing a spot beam if it is large enough and the bulb is in proper vertical and lateral alignment.

Smooth reflectors will always give better throw, but any 6V lantern or rechargeable spotlight is likely going to be geared towards throw regardless of its reflector type. Some spotlights do come with light OP reflectors and they tend to have much smoother round beams than ones with smooth reflectors.

BlueBeam22 said:

I assume you mean the reflector when you say "glass", as it is usually only optional diffuser lenses that are opaque. It depends completely on how textured the reflector is, however an average OP (orange peel) reflector is fully capable of producing a spot beam if it is large enough and the bulb is in proper vertical and lateral alignment. Smooth reflectors will always give better throw, but any 6V lantern or rechargeable spotlight is likely going to be geared towards throw regardless of its reflector type.

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No the glass. Was looking at par36 sealedbeams on the GE site. Believe some were listed as SP or I got the impression they would be SP due to the small degree of divergence but the glass looked textured. Can a SP sealedbeams have textured glass?

Does textured glass interupt the throw enough to be useless or do some SPs have textured glass?

A textured glass lens will not affect how the reflector focuses the light, but it can diffuse the beam and make it less of a thrower.

I've noticed that some of the "very narrow spot" sealed beams on the GE web-site are incorrectly pictured with a textured glass lens. Further research at an aircraft supply merchant's site (can't remember which) showed pics of the actual lamp, revealing the model # on the back and a clear lens on the front.