70-200mm f/2.8L IS -VS- f/4L IS -HELP-

---------------

Greetings and welcome to the forum.

What camera do you have and what other lenses?

---------------

The 2.8 is very heavy and will be more useful in low light. The other side of that is keeping the shutter speed up high enough for clear pictures. You might have to upgrade Your camera body to one that works better with higher ISO settings. IS stabilizes your motion, not theirs.

The 350D will handle either the F4 or F2.8 without any problems whatsoever - in fact, a couple of wedding pros use the F2.8IS with remarkable results.

The main responses you will have read concern "your needs for F2.8".

All I can add is .... "what are you needs for F2.8"?

Sorry but this is what all boils down to - your needs.

I'm not going to comment on the IQ of the F2.8 or I might have Ed on my arse!

Both are very capable of shooting ducks, bball, portraits etc., or even a landscape or two. They both offer superb glass qualities and build and their IS capabilities are infallible.

I chose the F2.8 over the F4IS simply because of my need for F2.8 for indoor wedding receptions without flash. From a distance, I can zoom up to the head table for candids with ease.

When mounted on my 20D with grip, the balance of this lens is perfect for me. Even better on a 1D-series

Don't get caught up in the reviews - try renting both these lenses and see the differences for yourself.

Goodluck

At the risk of oversimplifying

Stationary subjects--f4.0 IS

Moving objects--f2.8

The IQ difference is at best minor.

My experience--Your mileage may vary.

If you can afford the additional $700 cost and double the weight then go for the f/2.8.

The f/4.0 shoots fast moving objects just fine as long as the light is fairly good. I do shoot soccer at night under stadium lights with my f/4 and ISO 3200, but the results are, at best, marginal.

---------------

basman007 wrote in post #5152923
I've read on multiple sites that the 2.8 has some focussing problems at the low f-values.

Personally I've never heard this one, nor has it been my experience. Honestly, the f/2.8 lens holds the advantage for focusing in low light at any aperture. These cameras focus with the lens at their largest aperture, and the f/2.8 lens is letting in more light than the f/4, therefore it is able to focus faster then the f/4 version.

basman007 wrote in post #5152923
According to alot of people the f/4 is really sharp over the entire focal length, while the 2.8 isn't as sharp, mainly at low f-values and at 200 mm.

According to some review sights, the f/4 version is marginally sharper. In real world examples, I don't think its enough to notice. I'll offer the same advice that most others do when this topic comes up. Unless you NEED the f/2.8, get the f/4. But if you ever think you're going to need the f/2.8, then you only have 1 choice.

---------------

It's always good to have a spare battery handy.

I am currently in the very same situation. In fact I think I will make up my mind today and most likely buy the f/4 version from B&H.

Why the f/4? Because I don't think I will need the f/2.8 low light capability and the f/4 is $699.00 less than the f/2.8.

Quite honestly, this will be my first "L" lens. I keep second guessing myself about it really making a difference considering my level of expertise.

I will be using it on my 40D.

If you got the money, get the 2.8!

Just placed the order for the f/4.

Retired_97 wrote in post #5153790
Just placed the order for the f/4.

I doubt you'll ever regret it.