We are often asked the differences between, or among, fog, spot and driving lamps.

First off, spot and driving lamps are the same thing. The English term is “spot,” while the Americans tend to refer to these lamps as “driving” lamps. A spot or driving lamp has a clear lens with no fluting or block pattern (or, in some instances, just a few fine lines on the lens). It is designed to throw a long, thin, pencil beam far down the road: just the thing for high-speed night driving in good weather. The Lucas term for spot lamps was “LR,” or “Long Range.”

By contrast, a fog lamp has a block pattern or fluting on the lens, which shapes the light beam into a broad, low, flat pattern which works well in fog, rain or drizzle. Fogs will light up the sides of the road very nicely and help you see approaching wildlife, potholes, and other impediments to nighttime motoring. Lucas fog lamps were known as “FT,” or “Flat Throw.”

In practice, the type of lamp you choose for a classic car that will not be driven much at night, seldom in anger and practically never during bad weather, is mostly a question of personal taste. Some people prefer the more mysterious, aggressive look of the clear spot lamp while others think the fog lens is a better look for an old MG or Jaguar.

Which is “correct?” That depends upon the car. Most fog and spot lamps were added by their owners, sometimes long after the car had been purchased, with only a few fitted at the factory. Some cars, such as MGAs, could be ordered with either type of lamp, while Mark 2 Jaguars, for instance, were always equipped with fog lamps (except in the US, where bulb-type lamps were illegal, so a US-market Mark 2 would have come equipped with false round grilles in place of the Lucas Fograngers; we at Rogers Motors can rectify this situation, by the way! Check them out here).

In general, though, either spot or fog lamps can be considered “correct” on your classic British car. If you’d like some advice on which lamp to choose, send us an email and we will offer our thoughts on the matter.

And what of yellow fog or spot lamps? Why are they so special, and why are they so expensive? Yellow lamps are rare because they were normally only sold in countries like France and Switzerland which required yellow and did not permit white, or clear, lamps on cars. Most of the popular Lucas auxiliary lamps were available with yellow lenses, but only a very small percentage of them were made compared to the clear glass versions. We buy them whenever we can find them in our searches in the UK, but they have become very rare indeed, and a lot of people today prefer yellow because they are so unusual. We have some listed in our catalog:    Here are some: Lucas SLR700S Yellow Spot, and Lucas SFT700s Fog Lamp.

Then there are AMBER lamps, the rarest of the rare. These are a darker, almost brownish color, and are extremely hard to find. I think they were used primarily on emergency vehicles. We have one or two but very seldom see them for sale. As far as we know, nobody is making reproduction yellow or amber Lucas auxiliary lamps at this time, although the demand is great enough I would expect that somebody will figure it out sooner or later!

Incidentally, you can compromise by installing yellow bulbs in your Lucas lamps with clear lenses. We do sell yellow bulbs for this purpose.

There will be more on fog and spot lamps later.

Thanks for reading,
Geoff Rogers