Like the Tamron, this superzoom has also been around for a while, in various versions. It's very cheap, as the older versions can be found for usually less than 80-100$. It's cheap, it has reasonable range (pretty decent actually for FX), but is it any good?
+ very cheap
+ great range (not for DX though; 28mm is not wide enough)
+ good image quality (considering the price)
- in no way a better performer than, say, the Nikkor 18-200 VR
- heavy, extends quite a lot at 200mm.
- noisy, slow focus
|That's the Sigma I used for this review|
|And that's what it can do in good light|
- those checking out if they need a superzoom (before committing to a more attractive option)
- as a lens to sell a camera with (28-200mm looks good on the listing)
- wanting a lens to try a film camera with
- your only lens - simply not good enough and 28mm is not wide for DX
- anything past a short-term solution
- tele use without tripod (which is kind of an oxymoron for a superzoom)
You might have noticed that this review is quite similar to the one I wrote about the Tamron 28-200mm. And for good reason: This, like the Tamron is a very cheap lens, but, similarly enough, image quality is only acceptable (in daylight, when you can stop down couple of stops, I would dare call it 'good for the price'). The zoom is stiff, the focus bit noisy (but better than the Tamron), and the ergonomics overall quite obsolete and poor. Let's face it, this is not a practical solution for a lens. Good enough if you plan to experiment (for instance to see if you actually have use for a superzoom), or as a bundled lens if you're selling a camera. But that's about it.