Bushwalk Australia

Have noticed at times the head torch is a bit useless when there is fog, some rain types or cold breath is in front of you.

Is there a trick to using a torch at night in these conditions?

I am yet to experience needing to go somewhere in a whiteout.

Wondering if a yellow lense/filter would be of benefit...

Fog sits above the ground. You want a light that goes under the fog - a sharp cut off on the light to remove any light that goes hi. So many people in cars put their lights on hi beam .. absolutely the last thing you want.

Yellow helps too. Red is probably better than white. You don't need a bright light.

A GPS with the route aids navigation in any white out conditions.. even in a vehicle.

My feelings are to reduce your light intensity, if you can, to reduce reflection from the fog, and use some other navigation means…as per Warin’s post.

A

Yes it's the reflection that hurts. Low and lite, maybe shin lanterns!

Maybe a fog horn.

I always use the red light on my head torch. It cuts through the fog better and maintains your own vision better as the light reduces. I also angle it further down so it’s lighting up the ground in front of me under the fog more which improves the distance of ground visibility.

Around Sydney at the moment we use a boat.

Cheers
Roger

Red would be the colour I'd be trying for victory.

Why would a longer wavelength change things? Does the color really matter at all?

I thought the main thing was to aim/focus the light so that you aren't getting direct reflections back at your eyes.

Red light, but 'Spot' type might be a good combination.
Victory for the red wavelength.

Now...
want a couple of Lamingtons, a cup of coffee and a lie down in a warm bed.

Just hold your torch at waist height instead of having it on your head, when walking through fog. If the light source isn't at eye level, the main reflection also won't be at eye level.

All great info and thoughts folks.
May find a nice small but strong red torch somewhere, nothing ideal has popped up in my searches this far.
Kudos Lamont for going out to do some comparison testing.

Should've tasted the Lamingtons Neo... nearly inhaled two.

Color matters, warmer lights are better, as are those that produce a wider range of light, not something that LEDs do well. Spot-light type LEDs with deeper reflectors are a compromise. My best fog light is a Pelican where the led is facing back into the reflector from the lens, but it's a very specific design for industrial safety, not a great walking light. I'd say that chest mounted lights would be better than headlamps, if hand-held isn't a good option.

Red film or a lens cover would be valid options in many cases, but you are then compromising by using your light at a higher power level than you might otherwise.
This is also a case where a good quality light matters, as you will be affected more by the flicker of cheap PWM lights, ideally a directly controlled light (though at a higher cost) but a high-frequency PWM light is a good compromise. Combined with higher end lights being wider spectrum, and warmer lights being the best, even a good cool light will be better than a cheap one that edges into the "blue/purple" sort of color. Even if visibility isn't a factor, eye strain can be.

This little one shines red to 25m on one AAA.

Ok for campsite and nearby wildlife

https://ledlenser.com.au/products/p2

ribuck wrote:Just hold your torch at waist height instead of having it on your head, when walking through fog. If the light source isn't at eye level, the main reflection also won't be at eye level.

This is the best solution. The small water droplets in fog act as retroreflectors (similar to the glass beads in some road signs) so they tend to reflect the light back to the source. Wearing a headlamp on your head puts the light source close to your eyes, and so much of the reflection goes to your eyes. Keeping your light down near your waist means the reflection will not be towards your eyes.
This same effect is what causes dew to sparkle when you use a headlamp.

Just use a handheld torch so it's not refelectingg right back into your eyes. Also much better on rough ground to spot lumps and hollows as the parralax allows you to see shadows. personally never use a headtorch for tramping - much harder to see by than something at waist height.

madpom wrote:Just use a handheld torch so it's not refelectingg right back into your eyes.

Fog scatters the light in all directions. Someone could, incorrectly, think placing the light to the side would work.

What matters is not sending light into the fog ... but under it. The lower the beam of light the better.

Knee torches! Or gaiters with LED, go all out with multiple colours and disco mode.

I'll be walking a chilly Budawangs next week so expect some opportunities to try wandering around in the mist, white and red lights at different levels. Also no moon at night.

Neo wrote:Knee torches! Or gaiters with LED, go all out with multiple colours and disco mode.

Nice Neo!
You should be dancin' ........and I want pictures

Warin wrote:Fog scatters the light in all directions.

Yes, but equally in all directions?

Warin wrote:What matters is not sending light into the fog ... but under it. The lower the beam of light the better.

How to you convince the fog to lift up off the ground so you can shine a light under it?

Orion wrote:

Warin wrote:Fog scatters the light in all directions.

Yes, but equally in all directions?

Mie.png

Unless your light bean is 90 degrees to your sight line you get no reduction in returned light from most scattering effects.

Orion wrote:

Warin wrote:What matters is not sending light into the fog ... but under it. The lower the beam of light the better.

How to you convince the fog to lift up off the ground so you can shine a light under it?

That is the way fog naturally behaves.
Fog lights on vehicles have always been mounted low by manufactures and rally car people.
If they worked better higher they would have mounted them there.

Best I can find for now, a bit over 100g and runs for two to ten hours. Boogie down

https://www.hypop.com.au/products/godox ... -led-light

Warin wrote:Unless your light bean is 90 degrees to your sight line you get no reduction in returned light from most scattering effects.

Here's a plot of scattered light from natural fog:



As you can see, the vast majority of the light scatters forward, in the direction of the beam. The minimum is at about 100°, not 90*. And there is a local maximum at around 140°.

Warin wrote:

Orion wrote:How to you convince the fog to lift up off the ground so you can shine a light under it?

That is the way fog naturally behaves.

I have seen fog dissipating from the ground first. It's a common thing in certain environments but it's by no means a general behavior. I live in a foggy city near the ocean and most of the time it is sitting right on the ground (or it's hundreds of feet in the air). The inland valley "Tule" fog is often thicker and no less dense at ground level. I think there is a perceptual illusion that fog near the surface is thinner because you see the near ground through it.

Warin wrote:Fog lights on vehicles have always been mounted low by manufactures and rally car people.
If they worked better higher they would have mounted them there.

You put too much faith in the decisions of manufacturers and car owners. Here's an alternative hypothesis: fog lights are mounted and directed low to illuminate the road right in front of you and NOT the fog you're trying to otherwise see through.

Neo wrote:Best I can find for now, a bit over 100g and runs for two to ten hours. Boogie down

https://www.hypop.com.au/products/godox ... -led-light

Looking good.

Boogie down with this fog light extravaganza Neo !
A top cover.

I suggest you try the practical experiment with a torch & fog atvhead height and waist height. It works!

As well as the above reasons a directional beam from the torch at waist height will travel several meters before any reflection from it enters the focal area of your field of view. So you completely avoid those 1st few meters of high intestity reflections.

Orion wrote:

Warin wrote:Unless your light bean is 90 degrees to your sight line you get no reduction in returned light from most scattering effects.

Here's a plot of scattered light from natural fog:

That does not match the information you presented previously... it actually contradicts it.

Orion wrote:You put too much faith in the decisions of manufacturers and car owners. Here's an alternative hypothesis: fog lights are mounted and directed low to illuminate the road right in front of you and NOT the fog you're trying to otherwise see through.

Manufacturers and racing car owners do things that work in the real world.

Bottom line: Mounting fog lights low works much better than mounting fog lights high. End of my input. Bye.

A Fog War?!

How's the trials going Neo?
Anything to report?
C'mon brother-end this fog war now.

J. loves The Fog.

Sublime guitarist.

Alas that trip was clear. Only 'fog' was with a steady icy wind in early morning light.

Are you/will you be trying the red and/or
the waist/ankle height set-ups?
What HT are you using?