70-200 f/4L IS image quality near MFD?

I've seen posted in multiple places people complaining about the performance of the 70-200 f/4L IS near the minimum focus distance.

Do owners of the lens on the forum find that to be true?

I'm using the 135L presently, but am thinking that, while it is a wonderful lens, perhaps I'd be better off considering the 70-200 f/4L IS to expand the versatility while maintaining the excellent image quality. Poor performance at MFD would definitely shoot that idea down though...

Thanks in advance. I'm not considering it really seriously yet, but it is on my mind.

Dave

I never noticed an issue while I owned the 70-200 f/4L. In fact, for a while, that lens was the closest I had to macro and I used it for lots of close ups with good results.

Just a thought (I can't add any tech data to this because I don't have one):
Are people complaining about using this lens at the MFD on the camera normally, or are they using it with extension tubes?

What I'm thinking, is that this lens is a proper internal-focus lens. The front element doesn't move, just some of the inner elements move around. So differences in focussing are changing the optical formula every time.
So, focussing at MFD with no tubes, or focussing at the exact same object from the exact same distance, but with an extension tube (and the dial on the lens set somewhere closer to infinity), you're going to get 2 completely different optical formulae for each.

Which is better?
(don't ask me, that wasn't rhetorical. Although for 'true' macro lenses like the 100LIS, their formula is optimised for MFD with no tubes. As this lens isn't meant to be a macro lens, maybe it might work better with tubes and the focus dial at infinity?)

Not sure if this properly answers your question Dave, but I couldn't speak highly enough for the 70-200mm f/4L IS. The copy I used to own was spot on.

Here's three photos, the first at very close to MFD and the second two with extension tubes (36mm I think). I can't really see anything to complain about in any of them (IQ wise anyway).

http://farm3.staticflickr.com/2628/4...73ec50e9_z.jpg
Flutterby by Ben__Taylor, on Flickr


http://farm3.staticflickr.com/2668/4...ea4c26db_z.jpg
Yellow and blue collision by Ben__Taylor, on Flickr

http://farm5.staticflickr.com/4072/4...889e98b9_z.jpg
Palm pilot by Ben__Taylor, on Flickr

Dave, this is using 68mm of kenko tubes and MFD

http://4.bp.blogspot.com/-GdVzXrW1kL...26532+copy.jpg

This one is bare lens with cropping. Little or no sharpening. Can't remember the if I moved sharpening to 0 in lightroom or not.

http://2.bp.blogspot.com/-H9UdyiXjyH...26521+copy.jpg

I am very happy with the sharpness mine delivers at MFD and use it all of the time. These are all at the 200mm end.

Here are a couple more bare lens at MFD

http://2.bp.blogspot.com/-xe0jDVkkS1...5_07_16056.jpg

http://3.bp.blogspot.com/-htAJghBjtU...5_07_16043.jpg

DOF at MFD is very thin, maybe the people complaining encountered that challenge