How effective is IS?

Pete wrote in post #2210516
24-105 hand-held for 0.4sec... IS is pretty effective, I'd say.

The IS is impressive!

rklepper wrote in post #2211110
That is correct and most do not get the correlation.

I think they do... however, what gets me is the amount of people who say that f4 is no good and you must have f2.8, otherwise all your shots will be blurred because every subject is moving! A slight exageration on my part, but where does it all end? Why not say that f2.8 is no good for moving subjects and you need at least f1.8, no hang on, f1.4, oh wait what about f1.2, no that's no good either, to really freeze the action you need f1.0!

As for me and my inadequate f4, I just crank up the ISO - it's a pretty effective solution to not having f2.8, especially if you own a Canon!

I don't think anyone is saying f4 is no good, just that 2.8 is better.

The OP was really asking this question as a means of quantifying IS effect for STATIONARY objects. To that end, I'm not aware of any table that shows a direct comparison of IS effectiveness. In fact, I think it depends on the shooter to some degree. If you are prone to shake, then the IS would "buy" you more stops, would be my guess.

As to the side discussion of IS helping for shooting objects in motion, it just simply doesn't help. The car picture above is a good example. Although the car is relatively clear (although not great), the person is blurred to the point of almost not showing up because the shutter speed just isn't there. I see so many shots from people trying to shoot basketball and volleyball with the 70-200 2.8 IS and they usually end up dark, blurry, or look over PP'ed. Those same situations shot with fast primes are simply leauges ahead.

I had the f/4 non-IS and now have the f/2.8 IS. I still would choose IS because it allows me to handhold at 1/60 or something like that. Unless I'm looking for the bokeh being able to handhold at 1/60 allows me to use much smaller apertures and have a greater DOF. I guess it's about the expanded choices (speed/aperture/ISO) that the f/2.8 IS gives me and they make me happy. That being said, the f/4 non-IS was a great lens and much lighter -- but I had to shoot at 1/320 or 1/400 to get a crisp shot handheld and thus had less choices in some situations and no shot in lower light situations.

canonloader wrote in post #2212020
I don't think anyone is saying f4 is no good, just that 2.8 is better.

Not on any lens I've heard of!

AdamJL wrote in post #2209580
20 stop IS would

I realize this was in jest, but just to be clear.
No, 20 Stop IS would not do anything to help freeze subject motion. Only shutter speed helps there.