Help with 300mm F4L IS or 300mm F2.8L IS

I will be purchasing one of these lenses in the next couple of months (hopefully there will be rebates). I currently use a 20D. I would like to the use the 300mm with and without my 1.4x TC for sports, mostly soccer but some baseball. I shoot sports as an amatuer but I get paid and the people wanting me to shoot games is increasing. I would like to try the 2x TC for birds/wildlife in the future. I realize I lose AF with the F4 and IQ, but it is the only way I will get to 600mm anytime soon.

So, here is what I would like some opinions/recommendatio​ns on. Would I be better off biting the bullet and getting the 300mm F2.8L IS or getting the 300mm F4L IS and upgrading my body to the 40D? The 40D would give me faster fps and lower noise plus I could do the 40D/300mm F4L IS cheaper than the 300mm F2.8L IS.

What do you guys think? I am leaning 300mm F4L IS and 40D.

I would go and try both and see what you think of the weight of the 2.8,It is a amazing lens and you will get AF with 2X extender on your 20D.

The f/2.8 is better in every way with the exception that it is heavier and costs more.

No lens works better with Teleconverters..

I did try the 300mm F4L IS and was completely pleased with it. Of course, I did not have a 2x TC but it worked fine with the 1.4X TC. I was a little concerned about the AF speed with the 1.4X TC on it but it was very overcast for the entire week I rented the lens.

I would rent the 300mm F2.8L IS but it would cost almost $200. That is almost 20% of the 300mm F4L IS anyway.

Newbies get the f/4 IS not the 2.8 IS version. You won't use a 2x on the f/4 version. Mostly daytime, outdoor sports? I'd be looking at the new Sigma 120-400 and 150-500 OS lenses.

20D_Newbie was a bad choice in retrospect. I have been shooting with it several years now. I am no pro, but a little beyond newbie at this point. Most of my sports will be during the day but there will be some dusk/under the lights soccer. I shot a highly overcast game when I rented the 300mm F4L IS and it worked pretty well. I am not sure about the Sigma lenses. If I went with a variable aperature zoom, I would probably get the 100-400mm L.

I hav similar dilemma. I have a 300 f4 IS with 40D for wildlife photograpy. I is a very nice lens. Great image quality, fast and light, but I am planning to buy a 2.8. I think if you want the best image quality buy the 2.8 if enough a very good than buy the f4.

if your not über rich or making money on photography get the f4. They can be had for around 1k. Get a 1.4x for it. The f2.8 is a lot of weight to be carrying around. I thought about this and bought the f4 and a lot of other equipment instead. After a couple of trips with my gear I realized I would not want to carry a f2.8 very far. Heck you can get the f4, 100-400 and the 40d for way less than the f2.8!!!

I definitely vote for the 300 2.8L. It's tack sharp, not terribly heavy and the 2.8 pays for itself when your faced with low light situations, whether it be indoors shooting sports or Friday night football in a high school stadium.

If you want autofocus with 2x TC, then you'll NEED 300mm f/2.8 IS. If not, then it comes down to purely how often you use it, and whether having extra $2800 tied up in f/2.8 IS is worthwhile. If you don't care, then just get the f/2.8 IS. I hear it's like the best telephoto prime glass Canon ever made, and I'm sure you'll be happy with it!

Go for the 2.8 you know you want one lol,and if you don't get one you will be forever thinking about it.

I'd probably get the f/4 really. The /2.8 is of course better for many things but it is also a lot heavier, bigger and more expensive.

At least buy the /4 first and see if it works for you.

I like the 300 2.8. I took it out for a walk through a zoo today. The Iens is a bit heavy but bearable.
Here is a shot at 300mm.

I got the f/4. I'm going to get the f/2.8 as soon as I can. I'll let that speak for itself.

I think I have decided on the 300mm F4L IS and upgrading to a 40D. I just do not make enough money off this to justify the cost of the 2.8. Also, I think I would be scared to death to use it for fear of damaging it. But who knows, maybe in a year or so if my work increases the way it has over the last year or so.