Superzoom or seperate budget telephoto
 

The new Sigma 18-250 DC OS HSM lens sounds great, I've been considering the Tamron for a while but this sounds better. However which gives the better quality pictures (eg sharper), the Sigma (or Tamron) superzoom or the Canon EF-S 55-250mm IS? Would quality be better with a pair of lenses?

In short, yes - quality would be better with a couple (or more) of lenses but your choice depends on lots of other factors as well.

What camera do you have? What lenses do you already have? Is the "portability" of having a single lens important to you (and if so, how important).

As a rule of thumb, the less zooming you ask a lens to do, the better it will be (optically speaking).

I can go some way to answering .I bought a Canon eos50d with their own 18 to 200 zoom.Initially I was delighted with my shots but gradually I noticed it really struggled at the extremes especially the wide 18mm end where distortion and vignetting are very noticeable.

I now find the only time I use it is when I don't want to lug of stuff around .Otherwise my needs are met by other better and sharper lenses

more info on my kit
 

I've got a 400D, Currently three lenses, the original 18-55 non-IS sort which I would like to improve on, and a Canon 70-300mm non-IS lens which is quite good but IS would be better.
I try to take photos of birds at full zoom so don't want to lose too much at that far end but want improved sharpness. (Also got a fixed 50mm lens which is the best for sharpness.)

Amazon has the Canon EF-S 18-55mm f/3.5-5.6 IS Lens - Canon at £123 & the Canon EF-S 55-250mm f/4-5.6 IS at £170 so together about £300 vs the the Superzooms at about £400.
However maybe there is something better as the bottom lens whilst still in the budget range. If I went for two lenses then something that has a bigger zoom than 18-55 might be better as the "base" lens. The review of the Sigma 18-125mm in the latest PP sounds good though I've not found at the price suggested yet. If I could then that with the 55-250 would be about the same cost as the superzooms. Quality vs Convenience then. Would the pair be better quality?

Thats not a bad price for the Canon 55-250mm. And, yes the pair of lenses will [B]always [/B]give you better quality than a superzoom.

You've got a tricky situation here as for £400 to replace [I]both[/I] lenses you're not going to get much more than you've already got, perhaps just IS.

If you can stretch to it, I would get the [url=http://www.warehouseexpress.com/buy-sigma-17-70mm-f2-8-4-5-dc-macro-lens-canon-fit/p1012228]Sigma 17-70mm f/2.8-4.5[/url] which is around £250 and the [url=http://www.warehouseexpress.com/buy-sigma-70-300mm-f4-5-6-dg-os-lens-canon-fit/p1033291]Sigma 70-300mm f/4-5.6 OS[/url] which is abour £300 so it's £50 over budget but you might be able to find them cheaper.
If you cant' stretch that little bit further then I'd get the Sigma 17-70mm and the Canon 55-250mm IS.

Thanks Chris!