tfitz wrote in post #4242445
Hi!
... I also found that at F2.8 anywhere near the 200mm end was nearly impossible to shoot with. This is because when people move even slightly, that kind of razor thin DOF moves out to quickly, so I wound up shooting at F4 for almost the whole time. So while I think it's worth considering, the F4 is as well given the most likely shooting scenarios with it...
If you are "budgeting" for shutter speed, then you can *almost* consider the lenses equal. For static subjects yes. But this extra real stop can allow you to shoot at 1/500 instead of 1/250 and freeze moving subjects.
Now, there are other factors to consider as well. An f/2.8 lens will benefit from special AF points and sensors and give faster AF with EOS bodies that support this feature. Also, the wider apperture will allow the lens to behave better in low light AF, something that can be very important for certain applications, such as indoor sports, weddings, etc.
The lens is big but not as heavy in holding it as it weighs. The balance is good and the lens gives good grips. Weight is something that can be considered subjective. Larger people can always cary it with ease. But size is something more objective, especially when it comes to fitting the kit in a small gear bag.
I used to have the Sigma 80-400, and while that lens was heavier than the 7-200/2.8, I was able to carry it easily and hand hold it for hours. But I hated the big size of an "all-round-medium-zoom-telephoto". It was all I had for shooting longer than 85mm, and it was big. I sometimes carried with me the 75-300 instead.
So, my choice on the f/4IS was the fact it is as big as the normal 70-300 telephotos and easy to carry with me everywhere.