[afterburn]

When one of my collegues is going back to the US, he will need to go shopping for me again. However, I wonder what to do...

1) 70-200/f4 L IS v 70-200/f2.8 L IS

I know the measurable differences between the two: the f4 is a little sharper, and has less CA, the f2.8 has a little less vignetting and little less distortion. Probably mostly irrelevant in real world shooting.

However, what is the difference (if any) in color rendition and contrast?


2) I am looking for reach, and since I already have up to 105mm covered, would getting a prime like ie the 300/f4 L IS be a smart move? Or is the flexibility of a zoom just better?

The 100-400 is not an option for me, as push/pull zooms and me don't go together very well.

I do not plan to get much more than a single telephoto lens, and possibly a 1.4 extender.

I am not too charmed about non-Canon lenses, like Sigma as 1) I want IS since I mostly shoot handheld, en 2) (in the case of Sigma) I don't like the yellowish cast these lenses typically display.

Targetted use: Motorcycle racing, wildlife (think zoo), landscape, occasional bird and in case of a 70-200, indoor portraiture (don't seem me doing that with a 300mm prime).

So what I need is:
- Fast AF
- Range
- Reasonably fast aperture

Lens will be use on both the 5D and 30D.

I feel this pretty much point in the direction of the 70-200/f2.8 and a 1.4TC, which would give me a range of up to 200-448mm, depending on the camera and use of TC, while the f2.8 allows for available light indoor photography too.

But, on the other hand, I may be totally focussing on this lens and missing completely valid alternative.

Oh yeah, max budget is about $1500.