Help me rent a lens

Hi!
I have been using my venerable D40 for the last 2 years, and have perfected my technique with the also venerable Canon EF 28-135mm f/3.5-5.6 IS USM Lens. I can get beautiful pictures, however, I am eager to test my rig with a "better" Lens, I will of course Keep mine, and rent another lens just to try and see the results... Will not be buying as the economy is not good for now.

My main interest is family pictures, most of the time in dim light and with fast moving targets (toddler) which would be the best one? (renting price is about the same)


Canon EF-S 17-55mm f/2.8 IS USM Lens

Canon EF 24-70mm f/2.8 L USM Lens

Thanks

how dim is the light?...sometimes f2.8 isn't even fast enough, especially for a fast moving object..if you're taking pictures at 28mm f3.5...what kind of shutter speed/ISO do you usually shoot at?

as far as the focal length between the two, do you find yourself wanting to go wider than the 28mm you're currently at?

Speaking from a little bit of experience, if you want to take pictures of fast moving kids indoors, you need a flash. A f/2.8 lens is not going to get the job done unless perhaps you have a body with very good high ISO capabilities (7D). On my 30D, the 24-70 is not nearly fast enough to shoot my daughter in our house with available light. On the other hand, with my flash I can use my comparatively slow 17-85 and get good action stopping shots.

On the other hand, if you are just itching to try a new lens, I would suggest the 17-55. I have spent some time with the 24-70, and while it is a fantastic lens for image quality, the rest of the lens is a pain for me. Heavy, backwards zoom and a lens hood big enough to use as a minnow bucket.

DreDaze wrote in post #9069732
how dim is the light?...sometimes f2.8 isn't even fast enough, especially for a fast moving object..if you're taking pictures at 28mm f3.5...what kind of shutter speed/ISO do you usually shoot at?

as far as the focal length between the two, do you find yourself wanting to go wider than the 28mm you're currently at?

Thanks for the response:

Generally not as dim as an indoor concert or sport venue, usually I go on the 28-135 on 28mm at 1/100 up to 1/60 on ISO400 w/o Flash, of course that does not always yield the best result in the sharpness dept, and even, in some very rare occasions I use the pop-up flash to fill out a little bit and with that get some good results. (not a fan of flash photog yet as I understand very little about it that its probably not even worth it to buy a flash for now)

I hear you, it seems to be heavy, not the type of lens that you want to carry around your neck the whole day...

1) Flash
2) 17-55IS is the lens for a crop cam. or... the poor man's counterpart is the tamron 17-50 f/2.8