I'm heading off to walk from Lukla to Base Camp in the Himalayas, and looking forward to doing some great photogrpahy along the way. Gear and weight is restricted. I have a Canon EOS 60D. If I could only choose one zoom lens to take, which would be best? Also, which filters are recommended?
Bring one of those travel zooms.
Here is an overview of available lenses. Specifically those have a lot of focal length range:
Of course, the image quality from these zooms is not as good lenses with less zoom or even no zoom at all (prime lenses tend to have the best image quality). Also other lenses might give you an aperture of f/2.8, which helps a lot with low light.
So this is the general purpose answer. If you have specific pictures in mind, then other lenses will be better. If you are primarily interested in wide angle shots then getting something wider would help a lot, and you won't need the 200mm on the other side of the zoom.
Bring a polarising filter.
You should also consider a tripod. There are some lightweight ones, and also some that pack small (although you'd want it on the outside of your backpack anyway).
Two of the lenses I would consider would be either the EF-S 15-85mm f/3.5-5.6 IS or the EF 24-105mm f/4L IS. The 15-85 is lighter and covers a wide range of focal lengths. The 24-105 is built like a tank and covers a range of longer focal lengths. If you intend on taking mostly long range pictures, the EF 70-200mm f/4L IS is the way to go, but it is a little heavier and bulkier than either of the other two lenses. All three have IS and will allow you to handhold shots at lower shutter speeds when your subject isn't moving. IS will be especially useful since you probably won't have the luxury of a tripod. There are some monopods that can double as hiking sticks, and some of the higher end ones made from carbon fiber might be a consideration instead of a standard hiking stick. You might could lash it together with other walking sticks for a tripod in a pinch.
Since I'm assuming you'll be in a lot of snow, at a minimum you need a polarizer filter. Not only will it increase contrast and color saturation of a clear sky, but it will reduce the glare from reflected sunlight off the snow. Most polarizers also reduce exposure by around 2 stops but it wouldn't hurt to also carry a Neutral Density filter in the ND3 to ND5 range to stack on the polarizer when the sun is shining brightly on the snow. Remember to overexpose by 1-1 2/3 stops or so or the white snow will appear gray in your photos.
Requirements we know:
Requirements we don't know:
You could look at everything from a high quality prime such as the Canon EF 35mm f/1.4 L USM Lens, to the Canon EF 28-300mm f/3.5-5.6 L IS USM Lens. Those would be options if you truly are looking for the highest quality in their range. On the other hand, they are big and heavy. If you are most interested in weight, the Canon EF 40mm f/2.8 USM Lens is both the lightest and smallest EF lens currently. Some middle of the road choices would be lenses like the Canon EF-S 17-55mm f/2.8 IS USM Lens, Canon EF-S 15-85mm f/3.5-5.6 IS USM Lens, Canon EF-S 10-22mm f/3.5-4.5 USM Lens, or the Canon EF-S 18-200mm f/3.5-5.6 IS Lens.
Without knowing more on your requirements, it is anyone's guess what lens you should bring. I would highly recommend checking out this list of "Canon General Purpose Lens Recommendations" at the-digital-picture. As well as the list of "Canon Landscape Lens Recommendations" at the-digital-picture. After you have some lenses in mind, come back here and ask specific questions about which lens may be better for your intended subject, weight restriction, and quality that you desire.
I've been to the Sagarmatha National Park up to ~5500 m in autumn last year. I have a Nikon D90 and brought my ultra-wide angle, because I thought I need it. I didn't. It is way much too wide for the mountains. Everything gets very very distant with an ultra-wide angle lens like this.
Believe it or not: I shot 90 percent of my photos with a fixed-focal 35mm lens. I had another 50mm lens with me. However what I missed in many situations was a telephoto lens.
In retrospective I would recommend something like a 18-105 (in Nikon terms). If you can live with missing a few opportunities, a single 35mm will be fine. At least thats what I think.
Maybe this helps you. Have a nice trip!