Photography

Budget less than $100 but large aperture zoom these are contradictory statements. Even a good cheap zoom is more than $100 used.

A large aperture telephoto zoom would be something like the 70-200mm f2.8L which is even a used older version is still $800+ and it is going to be a 2-3lbs and a fairly bulky lens.

Not using flash and shooting in the moonlight or with no moonlight means that anything with a smaller aperture is not going to be able to get enough light even at ISO 6400+.

At $100 the only large aperture lens option that is in your budget is a used 50mm f1.8 or buying used manual focus lenses unless you find some insane deal from a private seller.

I would suggest if your hiking group ever does campfires to get some picture around a campfire instead.

If the light is not great or leaves peoples faces with to many shadows you could use a fill flash to fill in the shadows. Put an orange gel + diffuser on the flash and dial the power way down and it will not be nearly as distracting as a full power bare flash and you will keep the nice warm glow of the campfire.

Everyone carries either headlights or handheld lights, so there is some light from that.

If you set up shots you could achieve this with a tripod and long-exposure shots if everyone was willing to stay vaguely still. But you probably wouldn't get great portrait shots...

I see you mentioning that'd be tricky further on.

However you mention torches etc. and so there is another option....

I have a Canon EOS Rebel T3. My budget is in the couple hundred dollar range (less than 100 if possible).

Get a 2nd hand 50mm or 35mm f/1.8 lens.

Use the other people who have torches / head torches as a mobile lighting studio. Get them to provide light not just on your subject but on the surrounding area. Use that along with a high ISO and low aperture to take your photos.

Being a Rebel T3, you'll still encounter some noise over ISO3200 odd, but that's the price you pay for this kind of thing.

I really feel like getting creative with it that way is your best bet. Otherwise? With no light? I really don't see how.

For $100? Absolutely nothing except a flash unit.

Even the cellphones that might do what you want will likely use its flash and cost over a grand. And if you at any of their images, they have a decent source of light

It's night time, not daylight. You need light or long exposures to capture things in the dark.

Over a decade ago I went on a night hike on New Year’s Eve, in the wilderness, under the light of the moon. It was cold, foggy, and lightly snowing.

I wanted to bring a camera, but the only camera that would comfortably fit under my jacket was my old Nikon D40, with a 35 mm f/1.8 lens. Even back in those days the D40 was not considered all that great of a camera in low light. It was a cheap camera when I purchased it, and had very little value at the time of the shoot.

My solution was not to be worried at all about noise but instead try to get any photo that would capture my impression of the scene. I did use a monopod that would allow a longer shutter duration of ¼ second, and I set ISO as high as I could while still getting a usable image.

Sometimes I converted the image to monochrome:

https://flic.kr/p/dHhDVH

https://flic.kr/p/dHo5qm

https://flic.kr/p/dHo5j1

Other times I just underexposed:

https://flic.kr/p/dHo5EL

I thought they turned out OK, in a very impressionistic, rough but memorable manner. I didn’t attempt portraits, but you wouldn’t even see hardly much of anyone’s face in this situation.

It’s possible to get very good monochrome photos from even extremely underexposed raw files via a special technique: extract the raw, mostly unprocessed color channels from the file and sum them together. This bypasses the color processing which adds a considerable amount of noise.