Outdoor Sports - Looking for experienced advice

[intechpcx]

Hey guys, got a question for anyone that has some experience with shooting outdoor sports. My kids are both involved in Soccer (Football for the rest of the world) and Softball. I bought the Tamron 70-300 as a quick and cheap way to make sure I had the reach to get decent shots from their games. However, the lens has a max aperture of 5.6 at the longest lengths. So my question is that lens going to be fast enough to get quality shots at ISO 400 or less (given that I'll want to be shooting at a minimum shutter speed of 1/400? The games take place in the early evening hours (5:00-7:00pm) with the exception of my daughter's soccer games which will mostly be from 10:00am - Noon. The former timeframe is what has me worried.

I realize this is tough to answer without being in the exact lighting conditions that I'll be shooting under but I'm hoping that those with experience can make an educated guess as to how rough a time I'll have. Obviously with the D-Reb I could go all the way to ISO 1600 but of course I'd like to minimize the noise as much as possible. I'm just trying to get a feel for whether or not I should start looking for a somewhat affordable f/2.8 telephoto or if the Tamron will serve me well enough.

Oh, and I do plan to test it myself (by shooting in the expected conditions with the above settings) as well prior to the start of the season, but I'd like to get your opinions too.

[primoz]

I don't use lens like you bought (it's about money for me so I have different lenses) but I still think I can answer this, especially since I shoot mainly sport. :)
There's unfortunately no general answer. In most cases it will do just fine. If it will be sunny you are fine no matter what, and for cloudy weather just bump iso up. I don't understand why people are so scared to use iso800 for example. With today's cameras iso800 is perfectly useable. For most of editorial use iso1250 or even iso1600 is just fine (at least on 1dmk2). And with iso800 and f5.6 you should get short enough times even if weather is not perfect (sunny I mean :) ).
But there might be some problem with those matches on late afternoon. Ok in summer there's no problem, but in autumn or winter it will be dark already at those times (sorry I have no idea if they have matches then too or not). And even if there are lights which look bright enough it won't be enough light for photography. Personally I have sometimes problems on soocer fields with 2.8 lens and iso400 when they have tv lights and on smaller fields with worse lights it just gets worse.
Hope this helped at least a bit :)

[intechpcx]

Thanks Primoz, I appreciate the information. That's pretty much what I was looking for. The biggest reason I can't test this myself right now is the same reason you can't give me a hard and fast answer. With snow on the ground everything is brighter and being winter (OK, technically spring) the sun is lower in the sky than it will be later in spring when their games start.

With regard to ISO, the only issues I have with it are from things I read on this forum. I've heard so much about noise issues that I don't want to run into it if I can avoid it. Obviously, if its a choice of going ISO 1600 or not getting the shot, I'll take the high ISO anyday.

The perspective you've given me though was very helpful. I feel pretty confident that the lens will do alright, of course I'll find out for sure in about a month or so when the Soccer/Football games start.