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[url="http://www.opticallimits.com/canon_eos_ff/528-canon2470f28ff"]http://www.opticallimits.com/canon_eos_ff/528-canon2470f28ff[/url]
Very high field curvature at 24mm - therefore handle with caution ...
Ooh thanks; I was waiting for the long rumored new version, but I was about to get one of these for a trip (currently I am all primes) but looking at the review I think I'll go back to waiting....
Hi Klaus,
you (or the PZ team) wrote that this lens is not an "obvious choice" in this range - I'm just wondering what the obvious choice would be since there are not many alternatives.
I'm not much of a zoom fan myself and I don't often need zooms for the work I do, but I think that this range is pretty much essential for the working photographer. Whenever I have photo rehearsals or more important press shoots, this is the zoom I rent - for smaller jobs I get along with my Tamron 28-75.
Hi Klaus,
the resoloution figures arent bad at all. Okay, there is the field-curvature topic.....But compared to Nikons 24-70, the Canon is about 500 Euro cheaper (street price, new). But why the Nikon gets a better price-perfomance rattio?
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If you have a look at the sample image section most of the wide angle images show the field curvature issue.
Now if the lens does not perform in field conditions (unless you stop down to f/13) I don't really see how I can give it a good rating here.
The Nikkor isn't stellar in all aspects either but it doesn't seem to behave in such an extreme manner on the D3x.
genotypewriter
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[quote name='Klaus' date='17 June 2010 - 04:48 PM' timestamp='1276757317' post='577']
If you have a look at the sample image section most of the wide angle images show the field curvature issue.
Now if the lens does not perform in field conditions (unless you stop down to f/13) I don't really see how I can give it a good rating here.
The Nikkor isn't stellar in all aspects either but it doesn't seem to behave in such an extreme manner on the D3x.
[/quote]
Hi Klaus,
Let me start off by saying I'm not a zoom person at all. Not even Nikon's 14-24 or Canon's 70-200 2.8 IS II impress me. So it goes without saying that I have very little regard for the 24-70L.
However, the thing I want to understand better in your review is what should really be blamed for the behaviours that you observed. I understand how you discovered a difference in the field when you focused to infinity... but when considering all things practical, even f/11 at 24mm is enough on a 5D2 to get everything from 2m to infinity in complete focus at 100% view (from my experience). A part of the DOF function, as you know, is the viewing magnification and a 100% view of a 21MP image reduces DOF greatly.
Again, I'm not disputing what you've found here. What would be ideal here is you choosing the perfect/your favourite lens for this focal length (~24mm) and giving us a side-by-side comparison. This way we can see how much blame should go for the lens and how much should go for the DOF.
Also, in all fairness, I think the 24-70L is not that bad, for the zoom it is. If I wanted the best quality for any photographic application, I can't think of any zoom that I might choose over a prime. IQ-purists/aperture-junkies like me aside, anyone who's serious about landscapes wouldn't use this lens either. With the 24-105L IS around, the 24-70L is not the best choice for holiday/"everyday"-shooting either. These points have been established a long time ago and also by your review. So that leaves us with the question: How will this lens perform for the people who want to shoot at f/2.8 in the 24-70 range, against comparable lenses?
Thanks again for the reviews...
GTW
I have just mentioned the Canon 24-70 in another thread (prior to your review).... My own experience exactly matches your testing results. Not only Canon´s 24-70 is visibly worse optically (at 2.8) but also I was literally shocked by the sample variation of Canon´s 24-70 lens compared to Nikon´s 24-70. Maybe I just came across some bad Canon batch and good Nikon batch... But you experienced the sample variations too (4 copies to get a "good" one only!), this is strange and frustrating.
It is rather interesting that Canon is giving us the most megapixels in his sensors but his mainstream lenses are not able to feed it with enough resolution. Hope this 24-70 will be updated soon in the same way the 70-200/2.8 IS II was.
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[quote name='genotypewriter' date='17 June 2010 - 10:37 AM' timestamp='1276763867' post='579']
Hi Klaus,
Let me start off by saying I'm not a zoom person at all. Not even Nikon's 14-24 or Canon's 70-200 2.8 IS II impress me. So it goes without saying that I have very little regard for the 24-70L.
However, the thing I want to understand better in your review is what should really be blamed for the behaviours that you observed. I understand how you discovered a difference in the field when you focused to infinity... but when considering all things practical, even f/11 at 24mm is enough on a 5D2 to get everything from 2m to infinity in complete focus at 100% view (from my experience). A part of the DOF function, as you know, is the viewing magnification and a 100% view of a 21MP image reduces DOF greatly.
Again, I'm not disputing what you've found here. What would be ideal here is you choosing the perfect/your favourite lens for this focal length (~24mm) and giving us a side-by-side comparison. This way we can see how much blame should go for the lens and how much should go for the DOF.
Also, in all fairness, I think the 24-70L is not that bad, for the zoom it is. If I wanted the best quality for any photographic application, I can't think of any zoom that I might choose over a prime. IQ-purists/aperture-junkies like me aside, anyone who's serious about landscapes wouldn't use this lens either. With the 24-105L IS around, the 24-70L is not the best choice for holiday/"everyday"-shooting either. These points have been established a long time ago and also by your review. So that leaves us with the question: How will this lens perform for the people who want to shoot at f/2.8 in the 24-70 range, against comparable lenses?
Thanks again for the reviews...
GTW
[/quote]
Well, the field curvature issue did show up first on the charts because the corners were completely blurred at f/2.8 on the same image like the sharpest center. Upon defocusing the center towards closer focus distance the corner sharpness increased. This was also the sole reason to take a series of 10-15 shots at the same aperture but at different focus distances and the real world results just reflected the lab findings. So I can only report these findings here.
Field curvature is not THAT unusual - we've seen it in a couple of lenses although few showed a behavior as extreme as the 24-70L.
As far as alternatives are concerned - well, that's not my turn actually. :-)
A 17-55/2.8 on a 7D has certainly better corners than the 24-70L on the 5D II.
The old 28-70L is also supposed to be better than the 24-70L.
It certainly appears that right now there aren't any better alternatives on a FF Canon body right now. I know that the Tamron 28-75 is worse wide open (but good beyond f/5.6) and the Tamron's auto focus is quite bad. I don't know if the new Sigma 24-70 HSM is any good because I haven't tried it.
But no doubt the 24-70 range makes the Canon a 'bread and butter' lens for journalists, and most of the time the image quality is perfectly fine for print (or internet). Taking that into consideration, the review does not make it 'bad' lens - in fact for reportage it is still an extremely good and versatile lens.
Like some of the other members, I would never expect this lens to produce excellent fine art prints - for that it's usually better to use prime lenses.
genotypewriter
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[quote name='Klaus' date='17 June 2010 - 07:39 PM' timestamp='1276767542' post='582']
Field curvature is not THAT unusual - we've seen it in a couple of lenses although few showed a behavior as extreme as the 24-70L.
As far as alternatives are concerned - well, that's not my turn actually. :-)
A 17-55/2.8 on a 7D has certainly better corners than the 24-70L on the 5D II.
The old 28-70L is also supposed to be better than the 24-70L.
[/quote]
Sorry, I meant to say even f/11 at 24mm is not* enough to get everything in focus on a 5D2.
My point earlier in relation to alternatives was actually that. There aren't many options. Of course, the Sigmas are there but I don't their their colour or AF performance can match the Canon. There are many people who walk in to shops and buy brandnew lenses and they won't find the said 28-70L. The 17-55 IS is a good lens and I had it before... while it's really sharp, the bokeh and colour leave much to be desired. Also since it's equivalent to a ~f/4 on a FF, it's not fair to compare it against the 24-70L without considering the 24-105L IS on the 5D as well. Again, my point is, for f/2.8 shooting in the 24-70 range, this lens isn't all that bad.
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