All-in-One Super Zooms!
Look! Mounted to my camera! It's a wide-angle lens.... It's a telephoto.... It's SUPER ZOOM! These all-in-one long-range marvels are indeed tempting, but are they worth it? Maybe yes, maybe no.
There's a long-running debate as to whether fixed focal prime length lenses are better than zoom lenses that cover a range of focal lengths. At the same time, some on the zoom side of the debate have taken things even further in their attempts to achieve a one-lens strategy, with a single lens to handle all their needs.
It sure would be convenient not to have to change lenses so often. I often find myself shooting something that optimally falls near the end of the zoom range for some lens. Let's say I'm shooting with a 14-24mm zoom for instance and run up against the 24mm end. To go beyond that, I change lenses to the next zoom in line, in my case, the 28-70mm zoom. So far, so good. But by tweaking my composition slightly, I might just end up longing for the wider angle of view all over again, and thus change back to the 14-24mm lens. Back and forth I go as I work the subject. Each time I swap lenses, it not only takes up valuable time, it risks dust getting into the camera body and finding its way to the sensor.
The idea of not having to do this constant lens juggling is indeed tempting. If you include third-party manufacturers, you can find lenses covering such vast ranges as the Tamron 16-300mm zoom. It takes me four lenses to span that territory in what I usually carry. If one desired, they could turn their interchangeable lens camera (SLR or mirrorless) into a jack-of-all-trades tool with a single lens permanently attached to its face. But should you?
Such lenses do represent compromises, yet compromises can sometimes be extremely good options worth considering. Beyond the obvious benefit of never having to change lenses, here are a few more points, both pro and con, worth considering before you make your own decision.
On the plus side, all-in-one lenses are almost always more affordable than would be the purchase of several, more limited range zooms that cover the same focal range. This could make a meaning difference in the pocketbook for many. And carrying one around will clearly save you some weight compared to alternatives. This could make a meaningful difference how sore your muscles are at the end of a long day carrying all your gear on your back.
But even in this age of computer designed lenses, you will still pay at least some performance penalty when shooting with an extreme zoom. The contortions that the lens elements have to go through to cover such a wide range of focal lengths is indeed amazing, but it's simply impossible for them to be fully optimized throughout. Even among the best, you may see some loss of sharpness or perhaps a touch of chromatic distortion in the corners. This type of lens generally has quite a few glass elements too, and the resulting propensity for lens flare can make shooting anywhere near the sun problematic. Newer "nano-crystal" coatings can help mitigate this, but lens designers clearly have an uphill battle to come close to what simpler lens designs can achieve.
Lens hoods for all-in-one lenses can't be optimized throughout the zoom range either. A hood that works well at wide-angle end will prove woefully inadequate at the telephoto end. If you do some homework and shop around, you should be able to find a longer hood that fits for use at longer focal lengths. Carrying one lens with two lens hoods will still save you weight over carrying two lenses and two lens hoods.
All-in-one zoom lenses tend to have fairly modest aperture ranges. And it's not uncommon for their widest apertures to vary across the zoom range. A given lens may open as wide as f/3.5 at one end of the zoom range, but only be able to achieve f/4.5 at the other end. Metering with lenses that don't change aperture as you zoom is easier, but this variable aperture design does make sense given the relationship between the diameter of the lens opening and focal length. The front element would have to be huge to allow for a reasonably wide aperture at the telephoto end, and this would add considerably to the weight and cost of the resulting lens. See, everything's a compromise.
For those into using a lot of filters on the front of the lenses, an all-in-one zoom would obviously be a great way to ensure you only needed one size of filters. It can truly be a pain to have to buy filters in more than one diameter, or as an alternative, deal with step-up rings. And even if you did have a range of zooms all with a 77mm thread size, you would still need to deal with moving them from lens to lens, something that could be avoided if you could do everything with just one. And of course, this would mean less chance of fingerprints, another fringe benefit.
Because of their hybrid optical design, all-in-one zooms often allow for closer focus distances at the telephoto end than would a more conventional telephoto with the same maximum focal length. They would inherently be able to focus close at their wide end, and that benefit carries forward at least in part as you zoom towards the telephoto. This won't turn your all-in-one into a true macro lens, but it ain't bad, as a compromise.
Long ago, I bought a Nikon all-in-one zoom to use when I needed to save weight such as when hiking far enough that felt inclined to be kind to my aging body. As full disclose though, I must admit that I have rarely used it. At least for me, I've found that if its worth hiking to, its worth being able to shoot as well as I can. And that means lugging more and heavier lenses with me. But perhaps that's just me.
In the end, it's all a compromise. Luckily, you can often pick up a used all-in-one zoom fairly reasonably. It may not be able to replace your heavier gear in every circumstance, but it doesn't have to. If I helps out even some times, it might just be money well spent.