EF 70-200mm f/2,8 L USM Versus EF 70-300mm f/4-5.6 L IS USM

[Daniel Browning]

That comparison doesn't really make a lot of sense to me. It's like trying to decide between a dumptruck and a Ferrari. It's like comparing the 400mm f/5.6 and the 400mm f/2.8. They're just in a totally different class.

Wouldn't it make a lot more sense to compare two things that are a lot more similar, such as the 70-200 f/4 L IS and the 70-300mm f/4-5.6L? You'll find the 70-200 f/4 IS to be even sharper than the 70-300L (which is already quite sharp) in the overlapping range. Plus it's still up to a stop faster (though not two stops like the f/2.8) and still has IS. Since you said image quality (though that could mean just about anything) was your primary concern, I'd give the edge to the 70-200 f/4 L IS. The extra 100mm reach is the only area that the 70-200 loses out.

[Tack Sharp]

That comparison doesn't really make a lot of sense to me. It's like trying to decide between a dumptruck and a Ferrari. It's like comparing the 400mm f/5.6 and the 400mm f/2.8. They're just in a totally different class.

Wouldn't it make a lot more sense to compare two things that are a lot more similar, such as the 70-200 f/4 L IS and the 70-300mm f/4-5.6L? You'll find the 70-200 f/4 IS to be even sharper than the 70-300L (which is already quite sharp) in the overlapping range. Plus it's still up to a stop faster (though not two stops like the f/2.8) and still has IS. Since you said image quality (though that could mean just about anything) was your primary concern, I'd give the edge to the 70-200 f/4 L IS. The extra 100mm reach is the only area that the 70-200 loses out.

I'm comparing these two lenses because they are so different. I will be using it as a general purpose telephoto zoom as well as for portraiture. If I chose the 70-300, am I going to regret not having the f/2.8? and if choose the 70-200 am I going to regret the extra reach and the IS? By Image Quality I mean "sharp" images as most zooms outside the "L" range seem to be soft especially racked out.