If you don't want to switch lenses then why don't you consider selling your DSLR and getting a super zoom P&S like the S3? I'm not being critical - just wondering.
When it comes to covering a wide focal range you can't have your cake and eat it too.
These super zooms trade image quality for convenience. The 18-55 is not a bad lens. The 55-250IS is not a bad lens. But both of them are better than any single lens that covers the whole range.
The Tamron lens is rated better than the Canon & Sigma equivalents (but not by much - it's more a case of the lesser of evils).
Another option is looking for a good deal on someone selling one of the dual lens kit lenses? I notice you are in Ottawa and a quick look on Kijiji I found someone selling a 55-250IS New In Box and others selling gently used ones for less than half the price of the Tamron lens.
However, be warned. I first replaced my 18-55 with a 24-85 as I wanted more reach (The wide end is easier). It's a slippery slope though. I augmented the 24-85 with a 70-200 f/4L. That saitieted my appetite for a while but I began to love the sharpness & contrast of the 70-200 and stopped using the 24-85 after while. It wasn't long before I replaced the 24-85 with a 24-105 f/4L IS. Then I wanted to go wide again and bought a 17-40 f/4L. The Itch just wouldn't stop though and I upgraded the 70-200 f/4L to a 70-200 f/2.8L IS. Yes, my name is Bruce and I'm a "L" glass addict. I can stop any time. Honestly ...
When it comes to covering a wide focal range you can't have your cake and eat it too.
These super zooms trade image quality for convenience. The 18-55 is not a bad lens. The 55-250IS is not a bad lens. But both of them are better than any single lens that covers the whole range.
The Tamron lens is rated better than the Canon & Sigma equivalents (but not by much - it's more a case of the lesser of evils).
Another option is looking for a good deal on someone selling one of the dual lens kit lenses? I notice you are in Ottawa and a quick look on Kijiji I found someone selling a 55-250IS New In Box and others selling gently used ones for less than half the price of the Tamron lens.
However, be warned. I first replaced my 18-55 with a 24-85 as I wanted more reach (The wide end is easier). It's a slippery slope though. I augmented the 24-85 with a 70-200 f/4L. That saitieted my appetite for a while but I began to love the sharpness & contrast of the 70-200 and stopped using the 24-85 after while. It wasn't long before I replaced the 24-85 with a 24-105 f/4L IS. Then I wanted to go wide again and bought a 17-40 f/4L. The Itch just wouldn't stop though and I upgraded the 70-200 f/4L to a 70-200 f/2.8L IS. Yes, my name is Bruce and I'm a "L" glass addict. I can stop any time. Honestly ...