EF 70-200mm f/4L IS USM or EF 70-200mm f/2.8L USM........if the price were the same, which would you pick? i'd love to hear from someone regarding these 2 lenses. some of the volunteers at arizona highways use the 2.8 with extenders and are very happy. does the 2.8 give enough more to warrant the additional cost? i've heard that it can be too sharp (don't know what that means) thanks for any advice. do any of you use either of these.

Jeenie, I'll be the first to admit I dont use any of the above lenses. But your question interested me, so I did a little snooping, and here is my opinion: there is no doubt that both lenses have quite a bit to offer. Both lenses have argue-able differences, but for my money I would choose the L series IS lens. Why? simple, anytime you can get image stabilization in a telephoto lens thats a good thing. At f/4 the lens was meant to be shot wide open. Thats less fooling with the settings, it is quick, that means less drain on the battery the color and sharpness are excellent. The L means luxury. The lens is made of the finest materials available, to produce life like color and shape. It is lightweight, rugged, the photos it captures will give you years of joy. If you can buy the finest for the same price as second best, then I think this is a no brainer, purchase the f/4 L IS USM.

Hi Jen.
I chose the f/4 when I was purchasing my lens. I chose it for the same reasons Pastureyes stated - color, sharpness, image stabilization, etc. I made this decision based entirely on reviews and discussions like the one you have started here. It was a difficult decision though. The turning point for me was when someone mentioned the extremely shallow depth of field at f/2.8 . For me the quality of the image was far more important than the faster speed possible with the larger aperture ( the price tag on the f/2.8 was killing me too ). To my understanding the best reason to go with the f/2.8 would be lower light shooting possibilities. The other is a cost advantage when comparing to a longer lens. You mentioned folks using an extender on their 2.8 lens. The extender eats up an f-stop or two of light but gives them the reach of a larger much more expensive lens. It is a compromise. Using the extender reduces the light making the shutter speed slower for the same shot without the extender. So - a 2.8 with extender equals roughly a f/4 lens. If you plan to use an extender a 2.8 would probably be a better choice. If not, and your not planning to shoot indoor sports or other dim light - fast action situations the f/4 is said to have better color and clarity. So even at the same price it still boils down to how you plan to use it. Drove me crazy for days!
DP

I thought I should add this review site for you to check out as well. You will soon be suffering from information overload...
www.the-digital-picture.com
DP