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70-200/2.8 sharper than 70-200/2.8IS...reviews

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I enjoyed your post on the three lenses. Enlightening. Do you have images of the same subject taken with all three to demonstrate (for the monitor part) what you're saying (just for a visual)? In particular when you mentioned the difference in sharpness between the 70-200L 2.8 IS and 80-200L 2.8 in "absolute terms"...would be interested in seeing this demonstrated in an image if you have any handy.
 
If two different lenses (but same kind and models) were tested, it might be the other way around. While we all like lens tests, there are variations within the same model as has been particulary shown in the 24-70L and 17-40L lenses.

Would you trust a medication if there had only been one trial? This is also why I might read Consumers Union product comparisons and tests, but take into consideration that the small sampling that they use could easily lead to false conclusions.

Would it be possible to take a statistically valid number of the same model lens to test--of course not.

A lens test with the quality of the one that you quoted is still our best source of test material for that lens, but consideration should be given to variations of lenses within that particular product line.

MikeSp
 
I have done some testing on this also (a while back when I had a 1Ds). I can’t find the files any more but what I found was that if I looked really hard the old 70-200mm f/2.8L was a bit sharper than the f/2.8L IS. The difference that I saw was hardly what I would call significant in the center or near the edges. This is of course just one person’s experience with only one of each lens.

Greg

--



http://www.pbase.com/dadas115/
 
First, I don't have the means to post pictures, something I've been meaning to acquire, sorry about that.

Second, my point is that although I agree that the differences are visible, supporting the OP's posting, in prints (all things being equal), essentially they aren't. I contend the differences between the zooms make them different tools, despite the similarities.

Lastly, I find the discussion of lpmm intelectually interesting but of little "practical value". One of my favorite b&w prints is a Stieglitz in my hallway, that technically speaking, would qualify as a poor photo.

I don't want to put anyone to sleep, but when I used to write for an audio journal, I found most sets of specifications to be virtually useless when determining the listening value of any given piece of gear. They were helpful in classifying things relative to each other, but no value in deciding what made decent music.
 
Thanks for digging that up, Arto! So that little blurb you translated was what you're citing as proof that the IS version is sharper? Does the article include any data for the non-IS lens alongside the IS one? If that's the case, now that you have the magazine handy, do you mind just sharing the numbers they got, if even only at f/2.8, f/4, and f/5.6? Getting a hold of that back issue from the publisher could be kinda pricey and take a while, and I'm not interested in the rest of the magazine. Thanks!
 
As I mentioned in http://forums.dpreview.com/forums/read.asp?forum=1029&message=15420319 the 1Ds only resolves 56 lpm (less than either 70-200 resolves even at its worst) whereas the 20D can resolve 78 lpm, so the 20D would show the sharpness difference much more clearly. But that's interesting that even with a 1Ds you can pick up some difference in sharpness.

I think it's good for everyone to realize that there can be broad differences in usefulness of 100%-crop comparisons of sharpness depending not only what lens you're using but also what your sensor's pixel density is.

Once the 20D successor comes out, there will finally be a Canon camera out there that can outresolve just about any lens you put on it. (And it would follow that the sharpness differences between the IS and non-IS 70-200 will be a bit more visible.) I can just see all the new posts here about how everyone's lenses all lost their sharpness at 100%. :)
PeaceFrog said:
I have done some testing on this also (a while back when I had a
1Ds). I can’t find the files any more but what I found was that if
I looked really hard the old 70-200mm f/2.8L was a bit sharper than
the f/2.8L IS. The difference that I saw was hardly what I would
call significant in the center or near the edges. This is of
course just one person’s experience with only one of each lens.

Greg

--



http://www.pbase.com/dadas115/
Click to expand...
 
Yes, very true, the most important variables will always remain the photographer and the subject, not the lens and the sensor.
bsinc said:
First, I don't have the means to post pictures, something I've been
meaning to acquire, sorry about that.

Second, my point is that although I agree that the differences are
visible, supporting the OP's posting, in prints (all things being
equal), essentially they aren't. I contend the differences between
the zooms make them different tools, despite the similarities.

Lastly, I find the discussion of lpmm intelectually interesting but
of little "practical value". One of my favorite b&w prints is a
Stieglitz in my hallway, that technically speaking, would qualify
as a poor photo.

I don't want to put anyone to sleep, but when I used to write for
an audio journal, I found most sets of specifications to be
virtually useless when determining the listening value of any given
piece of gear. They were helpful in classifying things relative to
each other, but no value in deciding what made decent music.
Click to expand...
 
The point of my post was that the edges were not different. Both lenses performed very well at the edges even on a full frame body. Also, the resolution of the sensor is only one factor in the end sharpness of the image. The resolution of the lens also plays a roll. Do a little research and you will find the formula that expresses the relationship.

Greg

--



http://www.pbase.com/dadas115/
 
Right, my point was only that you need higher pixel density than a 1Ds has (e.g. a 20D) to really tell the difference in sharpness between these two lenses. I'm not sure what formula you're referring to, but I would be interested in seeing it if you find it. Were you thinking of something talking about like what's at this site:? http://www.vanwalree.com/optics/dof.html Is there a formula for "acceptable circle of confusion" that includes pixel density?
PeaceFrog said:
The point of my post was that the edges were not different. Both
lenses performed very well at the edges even on a full frame body.
Also, the resolution of the sensor is only one factor in the end
sharpness of the image. The resolution of the lens also plays a
roll. Do a little research and you will find the formula that
expresses the relationship.

Greg

--



http://www.pbase.com/dadas115/
Click to expand...
 
Thanks for not doing my homework for me, I learned a good deal in the search. I think I found what you were talking about at http://www.xs4all.nl/~diax/pages/Lens_res_uk.html The formula given is 1/Rt^2 = 1/Rs^2 + 1/RL^2 where
Rt = Resolution of the system (lens + sensor)
Rs = Resolution of the sensor
RL = Resolution of the lens

IOW that's Rt = sqrt(1/(1/Rs^2 + 1/RL^2)). So the 20D (78 lpm) with the non-IS at its sharpest (94 lpm) gives a total system resolution of 60 lpm, while the 1Ds (56 lpm) with this setup yields only 48 lpm. Take the IS lens at its best (75 lpm) and the 20D gives you an Rt of 54 lpm, while the 1Ds in this case puts out only 45 lpm.

I apologize for and take back my statement that the 20D successor will "outresolve" just about any lens. As the page I cited above talks about, it looks like a pixel density increase will always bring a system resolution increase.
lwestfall said:
PeaceFrog said:
The point of my post was that the edges were not different. Both
lenses performed very well at the edges even on a full frame body.
Also, the resolution of the sensor is only one factor in the end
sharpness of the image. The resolution of the lens also plays a
roll. Do a little research and you will find the formula that
expresses the relationship.

Greg

--



http://www.pbase.com/dadas115/
Click to expand...
Click to expand...
 
Daemeon said:
How photographers EVER got along without IS will remain one of the
great mysteries of the cosmos.
Click to expand...
Or how they managed without autufocus, or survived with only manual exposure, etc...

--
Misha
 
Sure you could have gotten that shot without IS, just turn up the iso.
ChrisDM said:
I realize that this is an equipment forum, where we discuss
equipment, but we are talking about 2 L zooms of identical range.
They both serve different purposes, though. The IS adds a great
level of functionality for certain types of shots, and if this is
useful to you, then get the IS model. If it isn't then don't get
the IS model.

You may get a few that say one is superior to the other, and vice
versa, ad nauseum. Don't buy the one that someone tells you is
sharper, buy the one you need... If after your purchase, you are
somehow dissatisfied with the image quality of your choice, I
guarantee you will not be satisfied with the other as well. They
both offer stunning image quality when used properly.

I have the IS version, and I use it. Here is a shot I recently got
at 200mm (320mm equivalent), at 1/40 second! I obviously wouldn't
have gotten this shot without IS. (This was also wide open at f2.8):



--

Chris
http://www.imagineimagery.com
Click to expand...
 
OK, I couldn't find a graph of this, so I made one myself. Check it out below, along with a zoomed-in view of just the lens resolution range that applies to current Canon lenses. The asymptote of each curve is that camera's sensor resolution. Among other things, this graph shows that as sensor resolution goes up, the sharpness difference between any two different given lens resolutions becomes increasingly noticeable.

Remember that according to WLCastleman's data the IS 70-200/2.8L ranges basically from 59-75 lpm, the non-IS from 75-94 lpm.



 
Those are the links the OP gave. (Thanks, forp!) Yes, under the MTF section of the non-IS review, the author says, "In the lab the lens showed that it is far from being qualified for retirement. In fact the performance figures beat both its IS sister lens as well as the EF 70-200mm f/4L - not by much (about a half "school mark") but clearly measurable. ... All-in-all the best Canon zoom tested to date." In the conclusion he calls it "an impressive piece of lens with superb build quality combined with an excellent optical performance which is, in fact, slightly better than in the rest of the family and comparable to the best fix-focals in its range." This agrees with WLCastleman's data at http://www.wlcastleman.com/equip/reviews/70_200/index.htm .
TheG said:
Take a look at the bottom of the review and in the MTF charts:

Non-IS
http://www.photozone.de/8Reviews/lenses/canon_70200_28/index.htm

IS
http://www.photozone.de/8Reviews/lenses/canon_70200_28is/index.htm

From the MTF charts we can see that the non-IS version is sharper.
Click to expand...
 
Good morning!

This test doesn´t include any numbers from the non-IS model, but they have tested it before as careful as thay test every other lens.

I trust this magazine and what they say, esprecially their lens reviews (they have looked the same way many many years and thet apply the same test methods for every lens they test).

So even if he states that the IS is better than the no-IS in only one sentence; that´s the way it is.

Obviosly there can be sample variations, but i assume Canon have send them the best examples out there of these lenses so they make good numbers :)

Maybe I make a big misstake by writing down these numbers here (all at f2.8 "radiellt" and center of image):

MTF @ 70mm: 0.73
MTF @ 135mm: 0.79
MTF @ 200mm: 0.68

Now, buy the magazine! ;)

--
Arto Pääkkönen @ home
 
Thanks for the effort but the focal length of the IS is much
longer than the others. So the comparison of bokeh is not valid.
Sharpness comparison of these is not easy either, the IS looks to be
less sharp but it is zoomed in so it would be easy to be wrong. Are
these 100% crops?

How did you end up with all these overlapping lenses? Are
you a collector?
 
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