70-200/4 L IS IQ?

I know there are several threads already but I am on a slow dial-up and most of the pictures are not loading. I also had problems at Digital Picture getting comparisons to come up correctly. Could someone please tell me (in words) how the new 70-200/4 L IS compares, IQ wise to the 200/2.8 and the 70-200/2.8 L IS. Canon's MTF charts indicate that the new /4 L IS is just a bit better than the other two perhaps. Wondering if I really need one or not.

Gene, see my latest postings at my site:

http://www.pbase.com/l​ightrules/70200f4lis
http://www.pbase.com/l​ightrules/5telezooms
http://www.pbase.com/l​ightrules/73v72f4is

What exactly is IQ? I've been confused about it for a while..

Image Quality - I know, took me a while too when I first got here .

Ves wrote in post #2252077
What exactly is IQ? I've been confused about it for a while..

LightRules - If I read correctly you are saying IQ is about the same for both 4 IS and 2.8 IS?

In this one -http://www.pbase.com/l​ightrules/image/698796​11 , the 2.8 IS really seems to take the cake for sharpness, with the f/4 IS seeming fairly soft. However, the street sign crop to the right side seems equally sharp between the two, yet the f/4 IS seems more saturated.

Yes, thanks R S Jr. I guess I'll just struggle along with my 70-200/ 2.8 L IS for now since the size and weight are not negatives to me. Was just out doing some testing comparing the 70-200 with TC's to the 300/4 and 300/2.8. The zoom can hold its own even with a 2X which does suprize me.

I just plain need 2.8. If I didn't, I'd trade up.

Ronald S. Jr. wrote in post #2252331
I just plain need 2.8. If I didn't, I'd trade up.

yep. won't be long now .

ed rader

gasrocks wrote in post #2252262
LightRules - If I read correctly you are saying IQ is about the same for both 4 IS and 2.8 IS?

Yes, for all intents and purposes. You just can't tell them apart while webviewing or on most-sized prints. If you pixel peep, it can still be hard to discern much difference. And if there is a difference, the variation can be attributed to subject distance and that particular capture's focus accuracy. When the playing field is all level, they're just about equal in every way. [Actually, the border performance on the f4 is slightly better IMO than the f2.8 based on what I've seen but not much to write home about here either.]

I just posted this test of 100% crops http://www.pbase.com …s/image/7012102​0/original

Yep, those all look the same in that last link. However, the f/4 still seems to have more saturation.

ed rader wrote in post #2252360
yep. won't be long now .

ed rader

No seriously..I really do need 2.8. It's a good thing it's sharp at 2.8, too, or I'd be looking for a 200 1.8. 2.8 is borderline for the stuff I do. I just have to have a fast ap. No chance in hell that f/4 would cut it with my stage photography.