It is not bad at all. Focusing distance of 2 m is almost fine at 200 mm with this lens (I would probably go at least 7 feet or even 8 to get good sharpness). It would be interesting to see if your lens is also sharp at 200 mm and MFD.
There are some, claiming that their 70-200 f/4.0 L IS is equally sharp at any focal length and MFD but there are many more who have this problem.
I have had 2 of these lenses, and one of them died, so I had it repaired (It was SUPER SHARP all the way across) the USM motor froze up. When I got it back, it just was not the same, so I sold it.
I bought a brand new one about 2 months ago, and it seems bad, not sharp with strange CA like distortions, date code UV 1205 (Dec 2007). Wonder if this is in the same bad "lot". I guess I can drop it off at Canon in Irvine since I live so close to them. Another "Lemon".
Jammy Straub wrote:
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.....
:
That was my understanding as well.
I saw a comparison on POTN between the 70-200 f4 IS with the 70-300 IS, both at MFD and the 70-300 was much sharper.
Its too bad too because I like to do close-ups with my 70-200, although I've heard that using this lens with ext tubes "gets around" this issue and allows for very good close-ups.
Forum members at DP review have summed it up that the lens is generally problematic at minimum focus distance at 200mm. A small price to pay for how great it is throughout the rest of the focal range.
yauyi. I can totally relate to how you feel as I had a super sharp copy of this lens. I sold it due to lack of action/reach. I bought a new one just a couple of days ago and it's nowhere close to my old copy. I had it adjusted and calibrated but still not as good as my old copy.
freespirit wrote:
Those buying new lenses: What is advisable - Are there any simple tests? Do you perform any tests as soon as the lens is in your possession?
One way would be to test your new 70-200 with a friend who knows they have a good copy and do a shot by shot comparison
Testing for this particular "issue" is simple... Set lens at 200mm, 1/500sec (just to be sure) and shoot something at it's MFD. Do the same thing at 135mm and compare results.
Daan B wrote:
Testing for this particular "issue" is simple... Set lens at 200mm, 1/500sec (just to be sure) and shoot something at it's MFD. Do the same thing at 135mm and compare results.
Thank you Daan for the simple test. The extremes are that you may end up with an excellent sharp copy or a very poor one. And in the middle you may have a soft mediocre lens. Sometimes when returned the manufacturer could just say its within specification!
Bearing in mind that you would want to keep your lens investment for many years, are there any other "scientific" or independent of the manufacturer or professional tests?
freespirit wrote:
Thank you Daan for the simple test. The extremes are that you may end up with an excellent sharp copy or a very poor one. And in the middle you may have a soft mediocre lens. Sometimes when returned the manufacturer could just say its within specification!
Bearing in mind that you would want to keep your lens investment for many years, are there any other "scientific" or independent of the manufacturer or professional tests?
As posted before in a simiair thread:
There is a difference between a lens being unsharp and not calibrated properly. Of course, when a lens isn't properly calibrated it appears to be unsharp. To get an idea how sharp your lens really is, you should do some tests by focusing manually. This way you rule out any possible AF problems. To test if the AF of your lens is calibrated properly, try this test: http://www.focustestchart.com/focus21.pdf
Daan B wrote:
As posted before in a simiair thread:
There is a difference between a lens being unsharp and not calibrated properly. Of course, when a lens isn't properly calibrated it appears to be unsharp. To get an idea how sharp your lens really is, you should do some tests by focusing manually. This way you rule out any possible AF problems. To test if the AF of your lens is calibrated properly, try this test: http://www.focustestchart.com/focus21.pdf
Thank you Daan for this test also.
Not that many of us would be keen to pay for a technically renowned optical lab to test our brand new 70-200 - but are there labs in Netherlands or UK available to us which can pinpoint lens quality problems.
Daan B:
Testing for this particular "issue" is simple... Set lens at 200mm, 1/500sec (just to be sure) and shoot something at it's MFD. Do the same thing at 135mm and compare results.
It is actually as simple as this but what I would like to understand (after looking at this problem for year) if there are really copies of this lens that are sharp at 200 mm and MFD and how these lenses perform at 70 mm (for instance).
freespirit wrote:
Thank you Daan for this test also.
Not that many of us would be keen to pay for a technically renowned optical lab to test our brand new 70-200 - but are there labs in Netherlands or UK available to us which can pinpoint lens quality problems.
ETB is a company that does all the (warranty) repairs for Canon here in the Netherlands. I always go there. I guess you can always send/bring your lens to Canon Service UK if you don't trust it.
f/5.6~f/8.0 also exhibit similar behavior. at MFD mine is also backfocus a bit too.
Normally I'd jump on this and say "get it calibrated" but there seems to be more to it than that, for sure. I doubt very much this is a calibration issue. The whole picture has a slightly milky look to it. In the 100% crop the resolution seems ever so slightly better on the board below the caterpillar. It reminds me of a problem I had with my ENG lens a few years ago when the doubler became impossible to focus. Dismantling it revealed an oily film over the surface of the doubler block. To this day I have no idea how it got there.
It also reminds me of the EF 135 soft focus lens which achieves its effect by subtle adjustments of spherical aberration. I can't imagine how this would happen in such a well established lens but maybe there's a mechanical problem inside. Perhaps the zoom elements are not properly positioned.
Yes at MFD 200mm wide open even the area in dof is still soft. Stopped down a lot, there tends to be sharper areas which on my lens seem far behind the focal point
I still don't see any 200mm MFD shots that are critically sharp. Still nobody has been able to produce something at 200mm MFD that is sharp, so I do fully agree that this is a design issue rather than copy to copy variation.
