Thanks for all the comments

To clarify my position... I am planning to use a lens like the 24-70L II mainly for event work. I will be at 2.8 about 80% of the time. Sharp corners matter, but aren't the highest priority. Money is. And of course AF speed + accuracy matter.

For those interested in such things, I've finally been able to look at sample variation in a reasonably large number of the 24-70 Mk IIs.

http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation

On the test bench I find the Tammie right between them: not quite as high as the Mk II, higher than the Mk I Canons. In my hands, though, because I'm rather shaky, the VC probably makes the Tammie the equal of the Mk II.

On the other hand, the Canon II is quicker to focus, especially on a 5DIII.

I still haven't decided if that would be worth the price difference to me.

Thanks Roger. Interesting read. Bummer to see the copy-to-copy variation is still there. Might explain some of the mixed reviews on resolution.

Thanks very much, Roger, for your efforts! I really appreciate the raw and massive amount of data on display here

But is this kind of copy variation typical of Canon's other L lenses, too? And are there any lenses with much less variation, e.g. the super-teles?

RCicala wrote:
For those interested in such things, I've finally been able to look at sample variation in a reasonably large number of the 24-70 Mk IIs.

http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation

On the test bench I find the Tammie right between them: not quite as high as the Mk II, higher than the Mk I Canons. In my hands, though, because I'm rather shaky, the VC probably makes the Tammie the equal of the Mk II.

On the other hand, the Canon II is quicker to focus, especially on a 5DIII.

I still haven't decided if that would be worth the price difference to me.


Wow, talk about an eye opener. Didn't realize there was that much variation on these newer lenses. Thanks for the great post.

RCicala wrote:
For those interested in such things, I've finally been able to look at sample variation in a reasonably large number of the 24-70 Mk IIs.
http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation


Thanks Roger. How confident are you in the accuracy and repeatability of results for each individual copy? You're probably aware of slrgear's old article about how tiny focus differences (even manually focused) translate into large variations of measured resolution, which lead them to create a dolly contraption to find ideal focus (Article Link)

Roger -- That't terrific information! Thanks for the large test groups.

Daan -- For your event work, it seems the Tamron may be the way to go. If you are able to try one out, I'm interested in your views on its AF speed and accuracy, as well as its IS effectiveness.

snapsy wrote:
RCicala wrote:
For those interested in such things, I've finally been able to look at sample variation in a reasonably large number of the 24-70 Mk IIs.
http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation


Thanks Roger. How confident are you in the accuracy and repeatability of results for each individual copy? You're probably aware of slrgear's old article about how tiny focus differences (even manually focused) translate into large variations of measured resolution, which lead them to create a dolly contraption to find ideal focus (Article Link)

I work with SLRGear.com quite a bit, we've visited and exchanged methodology. When we first started testing I spent a day with Dave and Rob, learning to align properly (Atlanta is close to Memphis).

I don't go into this in the posts trying to keep them brief, but for each lens we do the following:
1) confirm alignment via adjusting a 6 way mount analyzing images to be within 0.5 Degress of horizontal, vertical, and rotational tilt, and within 0.5cm of center of the chart.
2) manually focus using 10X Live view.
3) focus bracket 5 shots, 2 on either side of live view focus, analyze all 5 and choose the best.
4) repeat the test and take the better result of the two tests.
5) plot the data point.
6) go back and take the lowest 10% fo the test run, retest all of those lenses to be certain there's no error.

So I'm pretty confident in the data point (and sorry for boring the crap out of everyone who didn't want to know this).

From past experience, if we redo the entire test run on a different camera, the range, pattern, average and SD will be the same (assuming a reasonably large series). However the individual data points will shift around. Like many variation measurements the repeat will tend to have a 'travel toward the center' appearance. That is, the very best and worst lenses on this camera will be more toward the middle on another camera, while the middle ones on this camera will spread out higher or lower. That's just simple camera to camera variation.

As to the earlier question, for zooms, this is about what most f/2.8 lenses look like. Primes have about half as much variation as a very general rule. Consumer zooms seem to vary less actually, but part of thatis that the absolute numbers are lower (a 10% variation from 500 seems smaller than a 10% variation from 800) and because the apertures are smaller. If I tested these lenses at f/4, the variation would be reduced by nearly half.

</ boring lecture>


Roger

Your time and effort in this are appreciated roger. Good to see some data which I can use to base a decision on, rather than guesswork.

I use focal by reikan to micro adjust. It's also got the option to show the resolution of a lens over 10 shots, mainly to test focus variation per lens (that was really interesting to run!). I think it's in lines per inch.

Will the results from focal be able to be compared with your numbers do you know? When I get a new lens it would be really interesting to see where it is on the scale..

PhilDrinkwater wrote:
Your time and effort in this are appreciated roger. Good to see some data which I can use to base a decision on, rather than guesswork.

I use focal by reikan to micro adjust. It's also got the option to show the resolution of a lens over 10 shots, mainly to test focus variation per lens (that was really interesting to run!). I think it's in lines per inch.

Will the results from focal be able to be compared with your numbers do you know? When I get a new lens it would be really interesting to see where it is on the scale..

Phil,

I'm not sure of their numbers exactly, but I don't believe you'd be able to numerically convert the numbers to compare a Focal result to an Imatest result. But it should be fairly simple to have everyone put their own Focal numbers in a database, and that could be much larger than mine, which would be cool!!!

RCicala wrote:
For those interested in such things ...

Thank you, Roger, for your effort.

These articles are eye opening for me.
Another articles that I found very helpful/informative was the AF comparison.
Greatly appreciated .

great report Roger interesting results and I'm sure it took a lot of work!
Thanks

My copy is sharp corner to corner. Light falloff is not much of an issue because most of my shooting is between f/8-f/11. Still don't like the steep price.

RCicala wrote:
I work with SLRGear.com quite a bit, we've visited and exchanged methodology. When we first started testing I spent a day with Dave and Rob, learning to align properly (Atlanta is close to Memphis).
...
From past experience, if we redo the entire test run on a different camera, the range, pattern, average and SD will be the same (assuming a reasonably large series). However the individual data points will shift around. Like many variation measurements the repeat will tend to have a 'travel toward the center' appearance. That is, the very best and worst lenses on this camera will be more toward the middle on another camera, while the middle ones on this camera will spread out higher or lower. That's just simple camera to camera variation.
Roger

Thanks again Roger, your methodology seems perfectly sound. I'm really surprised by the variation on such a new lens. You'd think QA would be pretty tight on the first articles out of Canon so early in the production cycle.

It would be incredibly interesting to take the worst copy, a median copy, and the best copy and shoot a real-world scene to see how the MTF differences translate into an actual image.

RCicala wrote:
PhilDrinkwater wrote:
Your time and effort in this are appreciated roger. Good to see some data which I can use to base a decision on, rather than guesswork.

I use focal by reikan to micro adjust. It's also got the option to show the resolution of a lens over 10 shots, mainly to test focus variation per lens (that was really interesting to run!). I think it's in lines per inch.

Will the results from focal be able to be compared with your numbers do you know? When I get a new lens it would be really interesting to see where it is on the scale..

Phil,

I'm not sure of their numbers exactly, but I don't believe you'd be able to numerically convert the numbers to compare a Focal result to an Imatest result. But it should be fairly simple to have everyone put their own Focal numbers in a database, and that could be much larger than mine, which would be cool!!!

Yes, that would make sense.

And thanks for the reply

Klaus Priebe wrote:
My copy is sharp corner to corner. Light falloff is not much of an issue because most of my shooting is between f/8-f/11. Still don't like the steep price.


+1

I think the suggestion about real world images someone made is a good one, so I've appended the article with 100% crops of an ISO chart shot with one of the highest and one of the lowest resolving lenses.

I think it helps demonstrate that the number differences, while real, seem a lot greater than what you'd notice in the real world.

(I apologize for double posting, but seemed pertinent to both the ongoing threads. Maybe they should merge.)

From the updated article:

RCicala wrote:
BTW – if you feel the need to ask which was the highest and which was the lowest, then I’ve made my point.

Yes indeed .

I currently own the tamron 24-70 2.8....i have owned both the canon 24-70 2.8 v1 and the 24-104 4.0.....i have not had a chance to try the new canon 24-70 as of yet...for me the tamron is better than both of the older canon lenses,if the new canon had IS i probably would have dropped the additional 1000 dollars because i value IS in low light situations and find it invaluable.....for the same price i would have bought the new canon but for the additional 1000 dollars i opted to get the tamron due to the IS.....so far i have found it to be an outstanding performer and the differences I might see in sharpness with the new canon probably wouldn't impact me unless I was looking at 100% crops.....i do not rule out one day getting one on the used market when the new canon has been around for a while because sadly i tend to have a need to sample all new lenses and camera bodies lol

Personally, I've ditched any lens that wasn't a Canon L. I couldn't picture myself downgrading to a Tamron or Sigma. I will be picking up a 24-70 v2 to replace my 28-70L before next year' season.