Thanks all for the input...the reason I start looking for this L is that the 28-135 start glittering at the IS mechanics, and some times the pics are not quite as I wish...the Tamron is a good copy, but nowadays is a little off my interests, I did have it from the times of the 300D (aka Rebel or kiss), when the high ISO values was a problems, and the 2.8 helps me...
Also in my plans is a new 7D body (or maybe kit with something), but until than I wanna sort of my lens collection in a way...that collection includes:
50mm f1.8, 100mm f2.8 macro, 28-75 f2.8 (Tamron), 28-135 IS, 70-200 f4L...on my wish list is the 135 f2L and one prime WA...
My prior shooting is the 2 kids (2 and 7 y'rs old), and something around the house...
...when already have the Tamron 28-75 f2.8 and the Canon 28-135 IS ???
Well only you can tell..!
Let me ask some questions:
Q: Do you miss wide angle coverage?
You could/should consider a 15-85, 18-55, 18-135 or even a giant 18-270
As the 24-105 would properly need a "friend" like a UWA lens like Sigma 8-12, Canon 10-22, Tokina 11-16 in order to make a good base system.
I was thinking of the 15-85 with the 7D...
Q: Do you like the long reach of the 28-135, ie do you use 135 a lot?
Then the 24-105 is 30mm too short. 18-135 or 18-2xxx would be better.
I do use the 135 for the DOF in close pics...
Q: Do you like the 2.8 + the long part of the Tammy?
Then the 24-105 wont cut it, the 24-70 would be better.
same here, I like the DOF, but also need a sharp lens at the 2.8
Q: Do you like the 2.8 + the short part of the Tammy?
Then consider EF-S 17-55 and keep the 28-135 until you can get a good telezoom
AF wise and Optically the 24--105 is better, unless the 2.8 stuff...
I wanna use it as my all around lens on my 40D body, something good to take it easily with me when is neccessary...
My base system setup is Canon 50D
24-105
Tokina 11-16
Originally it was the 17-55 instead of the 24-105 but the offered Focal range did not fit my style so I traded it for 24-105 - I am a happy camper!
And some extras...
Canon 70-300
Tokina 10-17 fisheye
Sigma 30mm f/1.4
Majoren
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Nice world...'FROZEN'-it !!! (with digitalz).
828, 40D, U60, D10, ... what's next?!? some L's
70-200 f4L IS and 135 f2L on my wish list...hear me Santa ???