I appreciate your input. I have the 18-55mm IS, 55-250mm IS, 100mm Macro, 50mm 1.8 and a Sigma 10-20. So I'm not lacking range at all, just speed. I guess I'm after something in the sub-50mm range that's faster to focus than the 18-55. Also slightly faster aperture. I need speed!! :nuts:
Thing with the 18-55 - say I'm out in town and someone's walking towards me, by the time it's focussed, they're closer than they were, and out of focus. D'oh! :bang:
Ok, having looked at your line up I've made a decision!
The way to do it is this: ask yourself, what's the weak link in my lens line up?
Well, looking at what you have, it's not the Sigma, not the nifty fifty and not the macro. So you don't need to mess about with L lenses in that range.
The "weak links" are the kit lens and the 55-250mm.
And the 55-250 is BARELY a weak link really.
Then you look at the options to replace the kit lens:
16-35L
17-40L
24-70L
24-105L
And to replace the 55-250:
70-200L x 4 (ie. the 2.8 and f4 and IS and non-IS versions).
100-400L
Then go through them one by one.
16-35L - very expensive, very wide, very fast.
Discounted because it's eating into the Sigma range (and the Sigma is not a weak link lens!)
17-40L - cheaper, wide, not that fast.
Discounted because, again, it eats into the Sigma range (and it's not especially fast).
24-70L
The lens to buy! Why? Because it doesn't cut into the Sigma's range and is faster than the 24-105.
24-105L
Almost the lens to buy, but it's not as fast as the above (and because... well - see below!)
Then we move onto the 55-250 and its replacement.
100-400L
Discounted - very expensive, slightly unwieldy and really for people who NEED it (ie. sports / bird fans). That's just my opinion, but I would discount it for now.
Then the
70-200L's.
To cut a long story short, I would go with the 70-200 f4 IS.
I have always found the need for speed is greater at shorter shutter speeds (ie. for street shooting). Especially with IS, I think f4 is plenty fast enough! The non-IS f4 would be another option, but I personally would miss having the IS.
Also... then you have the range between 24-200 covered (with L glass). You have a great lens (the Sigma) for extra-wide. You have a nifty fifty.. just because! And you have a macro for macro.
It's expensive. In fact, looking at Amazon prices, it's double your budget at the moment.
Given that the weaker of the two "weak link" lenses is the 18-55, I would replace it with the
24-70L.
Ta da!