My Suggestion

It has long been my suggestion for amateurs looking to travel with only one lens to pick up an 18-200mm lens. This type of lens is built for travel with an 11X zoom that grabs decent wide angles and will zoom in for most closeup needs.

In testing options in the field, I found Canon and Nikon's offerings in this range to be first rate with Sigma's version being close behind.

There are a crop of lenses raising the bar for total zoom, such as the Tamron 18-270mm, a 15X zoom. While this lens is lighter than the Canon and Nikon 18-200mm versions, its quality is not as high.

However, there is a price difference that comes into play, realizing that saving \$100 or more may mean a few extra days on the road. Again, lens selection is about compromise and you need to decide which works best for you. DXOMark.com is an excellent place to look for lab-based testing data as a first stop in comparing lenses.

If you wish to buy a lens/camera combo, I've seen good results from both the Canon PowerShot SX20IS and Sony Cyber-Shot HX200V, both of which have a large amount of zoom as well as image stabilization. These cameras also offer a range of features suited to travel, such as a flip-out screen for easy self portraits and panorama modes (see note on stitching below).

Want to spend a little more and carry a lot more weight? The Sigma 50-500mm is a great lens, but HUGE! Otherwise, Canon makes a 28-300mm that is expensive, but smaller than the Sigma. Nikon also has a 28-300mm that is smaller still. These lenses work best on a full frame camera.

Now for some tips on how to get the most out of that lens. The obvious compromise of traveling with a single lens is that you have less flexibility and options when shooting. But there are several way to overcome these limitations.

Learn to Stitch for Wide Photos

If your lens isn't quite wide enough to take in the entire Coliseum or that beautiful old mosque in front of you, consider shooting multiple shots and stitching them in the computer afterward. This method takes some forethought, but can be fun.

There is a free program called Hugin, which will stitch the photos for you (as long as the scene is not overly complex or full of clear sky), but you need to ensure the best results with your camera in the first place. Tips on taking panorama photos (and the technique applies even if you are shooting just two or three shots to stitch) can be found here.

Get Close

If you bought a DSLR, chances are it came with a 'kit' lens. This is a cheap lens the manufacturers often include to help you get started taking photos. A popular size for this kit lens is 18-55mm which, for most DSLR cameras, produces an image close to what the human eye can see when zoomed to 55mm.

I see a lot of shots from people taken as the human eye would see them; from a distance with a semi-wide field of view. This can work for some shots, but a travel zoom lens can help you emphasis so much more if you get closer to your subject. For instance, take a look at these two images of a small tree on the edge of a canyon in Canyonlands National Park.

The first shot is from further back, but not much is leading viewers to focus on the tree. When I got lower and zoomed in, the tree becomes far more prominent in the image.

Use the zoom capabilities of that one lens you brought, but also move closer to highlight what you want your viewers to see.

The biggest compromise with a zoom is the maximum aperture obtainable. Because of mechanics while building zoom lenses, the maximum aperture is often f/3.5 at the widest zoom and between f/4-6.3 when the lens is zoomed out all the way.

What this translates to in the real world is less available light at a given focal length. For instance, a typical 18-200mm lens will be at f/5 while zoomed to 100mm. A corresponding 100mm prime lens will likely achieve f/2.8. That is a difference of 1 and 2/3 stops. In shutter speed terms, the prime might be able to achieve 1/125 of a second while the zoom would be limited to 1/40 of a second. 1/40 with a zoom of 100mm has a greater possibility to show blur, either from the subject moving or from the photographer moving. In anything less than bright light, this is certainly an issue.

Some lenses have a fixed maximum aperture across the length of the zoom, like the Sigma 50-150mm f/2.8 or a 70-200mm f/2.8. The compromise here deals with your pocketbook and arm strength. Lenses with a constant maximum aperture will cost significantly more as they are more difficult to engineer and manufacture.

They also contain more actual glass, as opposed to acrylic found in cheaper lenses, and metal, making them noticeably heavier. Both of those factors can play a part in the enjoyment of any trip. If you can handle both of those trade-offs, the fixed maximum aperture lens will give better results than a lens with a variable maximum aperture.

Go Wide and Go Long

The joy of a wide range zoom is in the ability to bring back a variety of compositions. Wide angle is not just good for all-in-focus landscapes and vistas, you can also get close and fill the frame with subjects. Portraits can even be had with the 18mm range and take on a new feel as compared to the more traditional 80mm shots.

Don't forget to take multiple shots of the same scene! The first shot is at 28mm on a 28-300mm lens. The second is at 300mm on the same lens.

Use the zoom at the long end to get closer to subjects that are already close. Single out just one flower instead of the whole flower bed. Show me the texture of the hills. Highlight the sunset with a wide shot and then zoom in.

Conclusion

If you wish to travel with just one lens, you should know what you're getting yourself into. Life, and photography, is compromise but it need not be a hard decision. Picking a lens like an 18-200mm will serve well in 90% of the situations a casual to semi-serious photographer will encounter all over the globe.

Have you found joy in traveling with only one lens? Let us know what has worked well, or badly, for you in the comments section below.