because now i only plan for buy 1 lens
the image that 17-55f2.8 look nice a lot compare to 24-105 f4, sharper
but the focal range of 17-55 f2.8 is not as good as 24-105 f4
i afraid that later if want shoot far object cannot =_=
the f2.8 is it really important?
Sorry to say.. but these 2 questions reveal that you haven't spend much time behind the cam to find out at least what you are into and what the parameter of the equipment really mean.
To save you money and frustrations I recommend that you stick to your kit lens, get a 50mm f/1.8 (about SGD 120.00) and shoot whatever you can see.
This will surely reveal which focal length is good for you (there is no 'good / bad focal length' if you don't specify at least the intended purpose) and whether f/4 is good for you or not. Not all 'far objects' need to be magnified by 400mm lenses, it can also make a lot of sense to keep them in the distance - but always depending on overall purpose.
Personally, I don't believe in "One lens for all purposes", no harm in having 2 or 3 lenses.