I just received my new 70-200 F/4 IS today, but after ~80 test shots in the backyard I'm not happy about the result I see. the softness issue is worst at MFD @200mm. Increasing distance to about 6ft from the subject did not improve much, same softness from f/4.0 to f/8.0. But, subjects at 20+ ft away are very very sharp wide open at 200mm, and only improve slightly stopping down to f/5.6 and f/8.0.
For those who had a bad copy, do you remember what lens code you got?
Mine is UW0205 (bought from JR)
I'll have to do a thorough test later on, on tripod, MLU, live view and manual focus. I had one last year and it did not exhibit this kind of behavior, why oh why did I sell that one.....arrggghh.
I had the EXACT problem, but looks like you figured it out alot faster than I did! It also had a front focus issue at certain mm, that I don't see on my other lenses.
I don't rember the lens code, but the manufacturing date was end of January 08, bought from Newegg. I sent it back to Newegg and will be getting another sometime next week. Should have arrived today at their warehouse.
brake79 wrote:
I had the EXACT problem, but looks like you figured it out alot faster than I did! It also had a front focus issue at certain mm, that I don't see on my other lenses.
I don't rember the lens code, but the manufacturing date was end of January 08, bought from Newegg. I sent it back to Newegg and will be getting another sometime next week. Should have arrived today at their warehouse.
thanks Danett....in the past I have owned and used an earlier production of the 70-200 F/4 IS extensively on my 30D and 1DMK2n, if such lens have problem it won't take me long to find out, I'm familiar with what a great copy of this lens is capable of...sigh. been kicking my backside ever since I sold the first copy of the 70-200 F/4 IS. As for lens code, my UW02 = 2008 February.
yauyi wrote:
I just received my new 70-200 F/4 IS today, but after ~80 test shots in the backyard I'm not happy about the result I see. the softness issue is worst at MFD @200mm. Increasing distance to about 6ft from the subject did not improve much, same softness from f/4.0 to f/8.0. But, subjects at 20+ ft away are very very sharp wide open at 200mm, and only improve slightly stopping down to f/5.6 and f/8.0.
My first one had a similar problem it was coke bottle from 135mm up to 200mm at distances of less than 20ft. Send it back.
My second one was stellar at everything (except MFD at 200mm, zooming out to 180mm corrected the sever abberations you encounter at that setting)
Interesting. A few weeks ago I got a brand new 70-200 f/4 IS lens, made in 2008 (forgot the month). Contrary to the expectations, the lens IQ was not any better than my old non-IS version. The IS lens was returned.
I have had a GREAT copy of this lens so I know there are many good copies out there, looks like I'm going to return this new one and go hunt for some older production used unit in B&S section, or get refurbished unit instead, I know for fact that the UU1102 that I had do NOT have softness problem of any kind, MFD @200MM wide open was very sharp on that copy.
This is what a good copy of this lens should look like at 200mm MFD wide open f/4.0:
Right...those old shots are very good, Yauyi.
It seems that even a zoom as well regarded as the 70-200 f/4 IS is vulnerable to the copy-to-copy variation plague.
The sharpness of that f/4 shot is nothing compared to what it can usually do. I have yet to see a critically sharp wide open 200mm MFD picture (Sharp in comparsion to normal use sharpness). I think my copy backfocuses at MFD 200mm. Stopped down a bit, it is possible to get decent sharpness but the focus point is always back a bit
I can't be bothered getting it calibrated cause it's fine for other applications
PetKal wrote:
Right...those old shots are very good, Yauyi.
It seems that even a zoom as well regarded as the 70-200 f/4 IS is vulnerable to the copy-to-copy variation plague.
yes i really missed the old one .
Here is the new one, 200mm f/4.0 somewhere around 4~5ft away:
resized:
Dawei Ye wrote:
The sharpness of that f/4 shot is nothing compared to what it can usually do. I have yet to see a critically sharp wide open 200mm MFD picture (Sharp in comparsion to normal use sharpness). I think my copy backfocuses at MFD 200mm. Stopped down a bit, it is possible to get decent sharpness but the focus point is always back a bit
I can't be bothered getting it calibrated cause it's fine for other applications
sadly, I think my new one has the same characteristic as yours, 70 to around 160mm is fantastic wide open but beyond that it sucks.
Looking through my old archive and found another MFD at 200mm of my old lens taken last year.
resized:
Hate to say it, but stop sellin off all your good stuff. tee hee!
No wait. Next time you find a good one, I'll buy it! Then at least you can come borrow either whenever you have sellers remorse!
I am hoping this bad batch issue will get sorted out soon, and will not become the new "Standard" for this excellent lens. Can people post lens codes, and see if there is something in common, to stay away from?
brake79 wrote:
Hate to say it, but stop sellin off all your good stuff. tee hee!
No wait. Next time you find a good one, I'll buy it! Then at least you can come borrow either whenever you have sellers remorse!
I am hoping this bad batch issue will get sorted out soon, and will not become the new "Standard" for this excellent lens. Can people post lens codes, and see if there is something in common, to stay away from?
i know i know...you can kick me in the bottom for that. but last year my 70-200 F/4 IS didn't see much action because the 24-105L covered all my shooting, and for reach 200mm wasn't long enough so I sold it. I did not have any remorse till the past few weeks when I needed that range again for different project.
The only good stuff I have left is the 100-400L, i ain't going to sell it for sure knowing my luck I would most likely get a crap copy if I rebuy another one in the future.
I'm curious if those MFD shots you've posted are really physically bumped up against the focus limit (ie did you set focus manually and then move the camera back and forth to aquire focus)? The one with the caterpillar shows the strange spherical aberration haze I encountered and the one with the flowers isn't nearly as sharp as the lens is capable of. I'm just saying,
It was determined right after the lens came out by a few members on here that the lens has a design characteristic that it's going to suffer from aberrations at MFD and 200mm's even in perfect copies of the lens. Stepping back just a few inches or zooming out a hard to 180mm largely alleviates the problem.
Unfortunately I think those rather informative threads are long gone
These lens variation problems with such a stellar (and pricey) optic are extremely discouraging.
Well, it is very possible that this MFD at 200mm phenomenon could be a characteristic of this lens, i'm going through a bunch of old archive and notice some of my close up flower shots were quite soft, back then I did not suspect it was a lens problem at all, i thought it was probably due to error on my part. I did not use measuring tape to check the exact distance from the subject so i can't confirm if the old copy had the same problem or not.
This was taken March 2007 with 1D MK2n, I think its very close to MFD, at 200mm F/4.0:
resized:
FWIW When shooting isolated objects (like the flowers) I find the AF usually compensates so that the image appears to be sharp @ MFD 160-200mm. However, if you shoot a flat test object (like a newspaper on the wall) you are not going to get sharp pics @ MFD 160mm-200mm. The only remedie is to back off a little.
My brand new one is UW0305. What does that mean? I have found it to be softer at 70 (2m) than at 200 (5m), not terribly so but the difference is obvious when trying to manual focus with 10X LV on 40D. Something wobbles too near the rear section when shake it slightly (normal?). Will do some real world shooting probably this weekend.
As for lens code, my UW02 = 2008 February. 
