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Archive 2012 · Is your 24-70 II a little soft at 70mm?
  
 
gdanmitchell
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p.3 #1 · p.3 #1 · Is your 24-70 II a little soft at 70mm?


badlydrawnboy wrote:
Does the LensAlign focus target not meet these criteria? It has a diagonal ruler designed to show front or back focus as well as a target with high contrast to focus on. I'm not sure what a better target would be than that?


Your problem isn't so much the subject you are "focusing" on, but the other variables you introduce into your "test" by hand holding the camera, using a subject that it not fixed, using focus and recompose, and so forth.

Again, you might or might not have a problem with your lens, but you won't be able to say with conviction one way or another until you test in a way that eliminates variables that you can control.

Dan



Dec 29, 2012 at 04:46 AM
gschlact
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p.3 #2 · p.3 #2 · Is your 24-70 II a little soft at 70mm?


Lens align counts, as it will have detail in front and behind the focal plane. If you feel it offers enough detail. Redo your test using Live View Contrast Detect AF (not phase detect), tripod, timer shutter release, lots of light and see if you get better results? More acceptable? If not send back lens. Let us know.

Guy



Dec 29, 2012 at 05:16 AM
badlydrawnboy
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p.3 #3 · p.3 #3 · Is your 24-70 II a little soft at 70mm?


gdanmitchell wrote:
Your problem isn't so much the subject you are "focusing" on, but the other variables you introduce into your "test" by hand holding the camera, using a subject that it not fixed, using focus and recompose, and so forth.

Again, you might or might not have a problem with your lens, but you won't be able to say with conviction one way or another until you test in a way that eliminates variables that you can control.

Dan


That's true of the first shots. But the later shots with the LensAlign target eliminate all of the variables you mention. They were taken with a sturdy tripod, center-point focus, low ISO, fast shutter speed, etc.

The same is true of the squirrel and tree shots, though I understand they're not the best subjects.



Dec 29, 2012 at 01:59 PM
badlydrawnboy
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p.3 #4 · p.3 #4 · Is your 24-70 II a little soft at 70mm?


gschlact wrote:
Lens align counts, as it will have detail in front and behind the focal plane. If you feel it offers enough detail. Redo your test using Live View Contrast Detect AF (not phase detect), tripod, timer shutter release, lots of light and see if you get better results? More acceptable? If not send back lens. Let us know.

Guy


Okay, I'll try that. If you have a suggestion for a better static target for testing I'm all ears.



Dec 29, 2012 at 02:05 PM
cputeq
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p.3 #5 · p.3 #5 · Is your 24-70 II a little soft at 70mm?


The LA target should be fine for general sharpness testing, though a larger focus chart might be better in this particular case.

However, I think most people have a problem with your methodology of how you used the LA chart. If you're testing for lens sharpness, not autofocus of the camera, you need to use live view, magnified, and carefully focus (manually) on the test chart and then fire away with a remote release, on a sturdy tripod and in good lighting. Try several shots like this, refocusing between.

This eliminates AF as being the culprit, or slower shutter speeds, camera shake, etc. Essentially, done this way, the only thing you cannot control would be how the lens renders the image at 70mm and 2.8

Good luck, though looking at your 24-70 vs the 50mm prime shots, the 24-70 looks pretty good and equivalent to the prime.



Dec 29, 2012 at 02:55 PM
badlydrawnboy
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p.3 #6 · p.3 #6 · Is your 24-70 II a little soft at 70mm?


cputeq wrote:
The LA target should be fine for general sharpness testing, though a larger focus chart might be better in this particular case.

However, I think most people have a problem with your methodology of how you used the LA chart. If you're testing for lens sharpness, not autofocus of the camera, you need to use live view, magnified, and carefully focus (manually) on the test chart and then fire away with a remote release, on a sturdy tripod and in good lighting. Try several shots like this, refocusing between.

This eliminates AF as being the culprit, or slower shutter speeds, camera
...Show more

Okay, thanks. If it stops raining today I'll re-do the LensAlign test with manual focus in Live view.

That said, one of the main reasons I've been doing all of this testing is that I've been having AF issues with several lenses and possibly my 5D3 body itself.

I just don't know whether it's the body or bad luck with the last 3 lenses I bought. Since everything is still under warranty I'll probably send it in to Canon to be sure.



Dec 29, 2012 at 04:27 PM
gschlact
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p.3 #7 · p.3 #7 · Is your 24-70 II a little soft at 70mm?


Per your note to me, you needed to use Live View AF too so that the Contrast Detect AF was used with lens align. You can try 10x manual focus also, but my experience is on the camera's LCD manual is not as reliable as the AF in live view. If remote on PC monitor maybe.

First isolate the sharpness of the lens per these recommendations. If it shows sharper results then you know you have AF issues with phase detectable camera and lens go to Canon for calibration. If the results are not sharper, then you need to determine whether the lens should be sharper by comparing to your sharpest lens using the same methodology. (Adjust distance of course for focal Keith differences so you can compare at 100% crops.



Dec 29, 2012 at 06:17 PM
badlydrawnboy
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p.3 #8 · p.3 #8 · Is your 24-70 II a little soft at 70mm?


I did as Guy suggested and took a few shots using Live View AF on a sturdy tripod. Shutter speed was 1/400 and although I don't have a cable release I used the timer release function to prevent camera shake.

I tried to do 25x focal length for both lenses so the 100% crops would be equivalent, but I think I must have been a little bit off with one of them because the crops don't have the same field of view.

I processed them identically in LR, increasing the sharpness from 25 to 50. No output sharpening was applied.

First shot is the 24-70 at 70mm f/2.8:



Second shot is the Canon 50/1.4 f/2.8:



It looks like they're pretty comparable in sharpness to me. You?

This is helpful because as Guy said, if I have any issues with sharpness and I've ruled out the possibility of motion blur then it's likely an AF issue that can be addressed by Canon under warranty.



Dec 29, 2012 at 10:31 PM
gschlact
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p.3 #9 · p.3 #9 · Is your 24-70 II a little soft at 70mm?


I am glad you now have the right process. I am on my I phone zoomed in looking at your posts and to me the stopped down 50 1.2 at 2.8 is sharper and better contrast deliniation. While I know it is decent lense, everyone else has indicated the MK II 24-70 is similar quality ass the 70-200 mkII so I actually would expect closer results. (Please confirm you posted 100% crops). Maybe someone else can comment on how close they should be. As another reference you can go to the website thy lets you compare two lenses to see if your small difference is typical. Please me us know. Also realize I am not saying your lense isn't good, I an just saying the other 50 is looking better in your post.


Dec 29, 2012 at 11:52 PM
gschlact
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p.3 #10 · p.3 #10 · Is your 24-70 II a little soft at 70mm?


Here is link
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=0&FLI=4&API=0&LensComp=115&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=4

I can't see on iPhone which is better?



Dec 29, 2012 at 11:59 PM
 

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badlydrawnboy
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p.3 #11 · p.3 #11 · Is your 24-70 II a little soft at 70mm?


The difference seems about the same to me as with the pictures I posted. But I'll admit I don't have a lot of experience evaluating test charts like that.


Dec 30, 2012 at 12:42 AM
gschlact
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p.3 #12 · p.3 #12 · Is your 24-70 II a little soft at 70mm?


I just checked on my PC the comparison charts.
I would say that on the digital-picture, the 50mm stopped to 2.8 is a little better on center and mid-frame, but worse on corner when compared to the 70mm at 2.8.

So, with that said, i would say based on your 100% crops of Lensalign you posted, that the results are as expected. Realize that at 25x FL distance, you are really stretching the capability of sharpness so both results here should be considered quite good. (If you have a known lesser quality lens, go ahead and post it as a 3rd comparison in your earlier post just to show how good your results are).

With that said, Now you need one more test - compare the Live View AF with non-Live Phase Detect AF using your 24-70 and 5d mkIII at 2.8. I would choose maybe 15x FL distance at 70mm, and use Lensalign in same fashion. REMEBMER to de-focus (manally turning lens, sometimes to the near, sometimes to the far side of focus between each shot) for the AF Phase detect test. THEN compare your best AF picture to the Live view AF results and see how close- (remember to use the same techniques as you previously used). Also, try to determine how close the bunch of the AF phase detect shots were in sharpness? Less good-lenses will have wider variance (I had this issue with a lens and boy is it frustrating to use). This ultimately will determine whether you need to send the camera and lens back to canon now that we know you ahve a sharp lens.

you are making progress.!

BTW - for sharpness in the Digital-Picture, you want to look at the clean edge and contrast between white and black lines etc. The better lens will have sharper edges (less fuzzy) and higher edge contrast (darker darks and lighter lights on the point of separation between black and white).

-Guy




Dec 30, 2012 at 01:22 AM
badlydrawnboy
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p.3 #13 · p.3 #13 · Is your 24-70 II a little soft at 70mm?


Okay, did some more testing as you suggested Guy.

I did a couple of shots with LiveView AF and a couple with phase-detect AF with the following lenses:
Canon 50/1.4
Canon 40/2.8
Sigma 35/1.4
Canon 24-70 II

I used 15x focal length to try to create a similar field of view in the 100% crops. (I must not have measured well with the 50/1.4, since it is quite different than the rest.)

Here's a sharpness comparison with LiveView AF. They're all sharp lenses, and I can't tell much of a difference.

24-70 @70mm f/2.8


Sigma 35/1.4 f/2.8


Canon 40/2.8 f/2.8


Canon 50/1.4 f/2.8


All of the lenses were just as sharp with phase-detect AF at this shooting distance, with the exception of the Sigma, which is front-focusing and is going to be sent back to B&H.




Dec 30, 2012 at 09:15 PM
gdanmitchell
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p.3 #14 · p.3 #14 · Is your 24-70 II a little soft at 70mm?


Part of what some of this reveals - and the digital-picture web site examples supports - is that we all may be a bit over-focused on the lens resolution measurements as a differentiator among lenses. Basically, all of these examples are very good and any of them could be used to produce excellent and very large prints.

It was also interesting to me to see the direct comparisons between various lenses and the EF 50mm f/1.4.

Additionally, it is worth noting that some of the differences become moot once you run the photos through typical raw conversion processes, which today do a fine job of equalizing various kinds of distortion and removing CA.

It recently occurred to me that I can do certain focal lengths in up to four different ways at this point, and that it might be fun and instructive to make a series of photographs at, say, 35mm using all four possibilities, take all of them through my normal post-production work flow, and then compare the results. Sounds like a project that I'll put on my to-do list...

Dan

Edited on Dec 31, 2012 at 02:44 AM · View previous versions



Dec 30, 2012 at 09:33 PM
badlydrawnboy
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p.3 #15 · p.3 #15 · Is your 24-70 II a little soft at 70mm?


I agree. All of these lenses are plenty sharp enough.

I still suspect my 5D3 may have an AF issue, but I'm relieved to know all of the lenses are fine optically.

I looked at the crops again, and the Sigma 35 does look slightly sharper than the rest. This wouldn't be unexpected in light of the MTF numbers and reviews, but it's possible it just appears to be sharper because the target is slightly larger than in the other shots.

I'm going to send my 5D3 into Canon just to be sure; then I can get back to making pictures and forget about all this stuff!



Dec 30, 2012 at 11:02 PM
Monito
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p.3 #16 · p.3 #16 · Is your 24-70 II a little soft at 70mm?


gdanmitchell wrote:
Part of what some of this reveals - and the digital-picture web site examples support - is that we all may be a bit over-focused on the lens resolution measurements as a differentiator among lenses. Basically, all of these examples are very good and any of them could be used to produce excellent and very large prints.


True. I chose my very-wide zoom on the basis of low distortion (and economy) because all the alternative zooms had more barrel distortion, cheaper and costlier both. They were all about as sharp. The only one that beats it that I remember researching was a very expensive prime.



Dec 30, 2012 at 11:18 PM
halfdome
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p.3 #17 · p.3 #17 · Is your 24-70 II a little soft at 70mm?


saneproduction wrote:
Mine is sharp everywhere


+1

Very pleased with the sharpness. It even beats my TS-E 24mm f/3.5L II and my 85mm f/1.2L II.



Dec 31, 2012 at 02:40 PM
AGeoJO
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p.3 #18 · p.3 #18 · Is your 24-70 II a little soft at 70mm?


Well, I love my 24-70mm Mark II, too and I can understand your enthusiasm for it but no, it doesn't "beat" the TS-E 24mm Mark II and 85mm f/1.2L II in a lot of aspects . They all live happily together... .


Dec 31, 2012 at 03:17 PM
Gust
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p.3 #19 · p.3 #19 · Is your 24-70 II a little soft at 70mm?


I'm not impressed.... look here at 70 mm to the 70-200/2.8 II, both at 2.8

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=0&FLI=4&API=0&LensComp=687&CameraComp=0&FLIComp=0&APIComp=0

my god thats real world. what a difference! especially in the corner.



Dec 31, 2012 at 06:22 PM
badlydrawnboy
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p.3 #20 · p.3 #20 · Is your 24-70 II a little soft at 70mm?


Well, I just got word from Canon. Turns out the AF system in my 5D3 does need adjustment. They didn't go into detail, but I'm hoping to get more information from them when I call later today. In any event, they said they're going to fix it by tomorrow and I should have it by Saturday.

I'm really glad to know I wasn't going crazy. As I said before, I've never paid this much attention to test shots, AFMA, etc. etc. because I've never had to. When I get a lens if it works well and nails focus in everyday shooting, I don't even bother with this kind of testing.

Can't wait to be done with all this stuff and have confidence in my equipment again! Also curious to see how the Sigma lenses perform after Canon adjusts my rig.



Jan 08, 2013 at 09:34 PM
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