I'm not sure if it's my emphasis on vacation travel this week or it's just that time of year when we get people considering moving up to a DSLR, but I'm getting the usual spring run of 18-200mm lust in my In Box at the moment. Several of these emails are from people wanting to move up to a DSLR for the first time, and I don't think they like my response.
The attraction of the 18-200mm is the so-called "one lens solution." It goes wide. It goes telephoto (except up close ;~). It has VR. It covers all the focal length range that a new DSLR user has probably ever used (28-300mm equivalent). So it's a natural, right?
Not so fast. Essentially, all you're doing by buying a DSLR with an 18-200mm and never changing lenses is buying a somewhat better "bridge camera." Every maker seems to have one these days. The question is this: what are you really gaining by foregoing a bridge camera for a DSLR with one lens? A fair amount, as it turns out. I've got a Fujifilm HS-10 sitting on my desk at the moment, so let's do some closer analysis (I'll compare against, say, a D5000 with 18-200mm):
- Pixels. The DSLR wins by a small margin. But most people seeking all-in-one camera solutions shouldn't be all that interested in pixel count. 10mp is usually more than enough for their purposes.
- Low light. The DSLR wins, but not by as much as most people think these days.
- Lens. The bridge camera wins, hands down. It has more focal length range, usually a faster aperture at wide angle, and almost certainly does credible macro.
- Size/Weight. Another win for the bridge camera. It almost certainly is smaller and lighter. If all you're carrying is one camera/lens, you're already thinking about this issue from the beginning.
- Autofocus. Usually a DSLR win for motion, but I'd say the bridge camera is the winner for non-motion. That's because a contrast-based system shouldn't miss, while a phase detect focus system has tolerance and needs to be mastered to be accurate. Face detection also tilts the game towards the bridge camera, too.
- Speed. Start up speed and shutter lag go to the DSLR, though bridge cameras are getting better.
- Cost. The bridge camera wins hands down. And the further up the DSLR lineup you go (usually to get better high ISO results or faster AF), the more the difference becomes.
- Video. Dare I say it? Most bridge camera video has more features and resolution than the majority of Nikon DSLRs.
It seems to me that the reason to buy a DSLR is the flexibility it affords. Of course, when you're on vacation with the family, that flexibility could lead you to carrying too much and taking too much time to get your photography done at each stop. Thus the temptation to reduce the DSLR to essentially a bigger bridge camera via the 18-200mm lens.
My solution is in between something like the HS-10 and the D5000 with 18-200mm: an m4/3 body with one to three lenses. Same pixel count, closer to the DSLR on low light ability, no difference in lens (Olympus now offers a 14-150mm lens, which is pretty much the same as an 18-200mm), big reduction in size and weight, and closer to the DSLR on focus ability. The silly thing? It might cost more than a DSLR! I hope Olympus has milked the price for all its worth, because long term it won't hold up. The m4/3 solution should be priced between the bridge camera and DSLR solution, but isn't. That puts it more into the "luxury" category than the m4/3 products actually manage.
But back to my main point: I'm not a fan of reducing a DSLR into a one-lens pony. It's not that difficult to find and carry a handful of useful lenses that start to show off how a DSLR can take your photography into new territory. So I say be careful about taking this route. You're buying high and using low.