24-70 at 2.8

[photomarche]

<p>Hi,<br>

Here are two shots taken with D800 and 24-70mm, both at 70mm, AF-S , live view focus.<br>

I used tripod shutter cable and MUP, they are taken a few seconds away from each other under the same light condition.<br>

From the crops, I noticed that the image taken at f2.8 is a slightly softer.<br>

According to photozone (http://www.photozone.de/nikon_ff/456-nikkor_afs_2470_28_ff?start=1), the resolution at 2.8 70mm drop at the borders, so no surprise there.<br>

However, even in the center, the image looks a bit software compared to the one taken at f4 (raw file comparison)</p>

<p>24-70mm at f2.8<br>

<img src="C:\Users\BEBE\Pictures\D800\test24_70@f2.8" alt="" /></p>

<p>24-70mm at f4<br>

<img src="C:\Users\BEBE\Pictures\D800\test24_70@f4" alt="" /></p>

<p>I did other tests and all images taken at 70mm f.28 looks a bit soft.<br>

I usually use this lenses stepped down for landscapes, it is very sharp.<br>

Could it be a focusing issues?</p>

<p>What is your experience with this zoom lenses?<br>

Thanks</p>

<p> </p>

[photomarche]

<p>photos uploaded:<br>

http://www.photo.net/photo/17020593<br>

http://www.photo.net/photo/17020592</p>

<p> </p>

[michael_bradtke]

<p>No lens is at its sharpest wide open. But you should reshoot your test and try to do everything the same.</p>

[ilkka_nissila]

<p>Photozone doesn't use the D800 for testing, so your camera is a bit more sensitive and is likely to show differences that the D3X doesn't show. </p>

<p>That said, I find the 24-70 at 24mm to be sharpest at short to intermediate distances (i.e. 2m) and gets softer towards infinity. At 70mm I find the opposite effect: it is super sharp at long distances (landscape) and gets a little softer up close (at portrait distances). This is just empirical observation from many years of using the lens in practice, not the result of a rigorous test. </p>

[elliot1]

<p>Are you looking at the unprocessed RAW files or in-camera JPGs?</p>

[elliot1]

<p>Sorry, I missed your note about RAW - I will check my lens when I have a chance.</p>

[elliot1]

<p>I have always found Nikon pro glass to be just as sharp wide open as when stopped down.</p>

<p>I shot this image with the D800 and 24-70mm lens (on a tripod). </p><div></div>

[elliot1]

<p>These are the crops at the various apertures.</p><div></div>

[n_s6]

<p>how are you focusing? Take a picture w/ LiveView and compare. if it's sharper you need to fine tune focus.<br>

my copy needed a +14 adjustment.</p>

<p> </p>

[frank_skomial]

<p>"<em>to be sharpest at short to intermediate distances (i.e. 2m) and gets softer towards infinity</em>" -</p>

<p>They test production lenses on relatively short optical bench, where longer focusing is not feasible.</p>

<p>I recommended they use the mono rail road running from Tokio to Osaka as optical bench, then they would have suffiently long test bench..:)</p>

<p>Interestingly, some 25+ years ago, on vacation driving around national parks, shoting the same with old German camera and Zeiss lens, and another top of the line new Canon, and results were surprising that Zeiss pictures were sharper when focused on far away places, while Canon was better on close focus subjects.</p>

<p>Why it was like that ? - perhaps a different grade lenses were used.</p>

<p>Explanation from an expert at Olympic Camera in LA Downtown was startling and perhaps hard to believe, something like this:</p>

<p>"Lenses made in Japan were tested on short optical benches and achieved high performance data to get printed in publications and advertising. Lenses made in Germany have already established good reputation and they care less of advertising hype, and more about real life pictures".</p>

[photomarche]

<p>I am focusing with Live view, and shots are taken with the same settings (ISO 100, tripod, cable, MUP, raw), just different aperture.<br>

Did more testing at 70mm on the D800. From observation, it still looks softer at f2.8 at any distance, however it is more visible on the short distance (I tried 2m away). Increasing sharpness in LR (for example from 25 to 50) helps to improve the result a lot. Not a problem for landscape as I would step down, but I hoping to use this lenses for portrait as well. <br>

@N S, thanks for the advice, I will try AF tuning as well.<br>

Regards</p>

<p> </p>

[photomarche]

<p>My comments above, apply to the D7000 as well. Noticed a bit of softness at f2.8 at 70mm (distance from the subject 80cm)</p>

 

[elliot1]

<p>Francesco, can you post some side-by-side crops that illustrate the issue?</p>

[photomarche]

<p>Yes, I put the links on the previous page:<br /><br /><br />http://www.photo.net/photo/17020593<br />http://www.photo.net/photo/17020592<br /><br /><br>

link to both images side by side<br>

http://www.photo.net/photo/17024335&size=lg</p>

<p> </p><div></div>

[elliot1]

<p>The exposure is different between the two. Where exactly is the AF point? How much of a crop from the original image are these?</p>

<p>The front of the large leaf in front appears to be in focus in both shots and I suspect that is where your AF point is. As DOF can be narrow at f2.8, this could explain the OOF areas rather than issues with your lens.</p>

[dan_south]

Did you focus manually using live view? Or did you use live view autofocus? If manual, do you need corrective lenses for

your eyes?

 

If you are shooting in live view, why did you use mirror lock up?

 

Why are you trying to evaluate sharpness on a 3D subject? Were there no planar subjects handy, such as a brick of

wooden wall with lots of fine detail?

 

Where on the subject did you focus? Which leaf? Is the focus sharp at that point? Why would you expect the image to

be sharp away from the plane of focus when shooting wide open?

[Peter_in_PA]

<p>Elliot writes</p>

 

<blockquote>

<p>I have always found Nikon pro glass to be just as sharp wide open as when stopped down.</p>

</blockquote>

<p>I wonder, to be honest, about your testing procedures then, Elliot. I am pretty sure that virtually no lens is as sharp wide open as stopped down one or two stops. I have personally measured this with a half-dozen (mostly consumer) lenses. Not a <em><strong>single</strong></em> one of my lenses Tokina 11-16, Nikon 18-70, 70-300VR, 35 f1.8DX, 50 f1.8D, 55 f3.5 micro AI, 105 f2.5 AI) is as sharp wide open as it is stopped down one or two stops. Not one... And the tests I've seen online and in magazines for the pro glass finds the same, predictable, dynamic.</p>

<p>But often these tests we do as amateurs wide open don't show anything about lens sharpness and everything about what happens with very thin plane of focus due to a wide aperture.</p>

[garypeck]

<p>What I think you're discovering here is the uncanny ability of the massive sensor in this camera to demonstrate ANY discrepancy in any lens. It was a shock to me that lenses I had believed to be spot on simply weren't up to the challenge. You probably need to "tune" the zoom lens (plenty of threads here on that) to achieve max sharpness and contrast.<br>

The D800 will display the true abilities of any lens - Wide open means soft in almost all glass - that said, viewing at full frame or "fit" in LR will show how successful that image is. Pixel peeping will only create unnecessary concern and there are certain advantages to the softness your lenses are producing.<br>

Your target is pretty flat lite - and it's hard to see coma or CA or much of anything in the image. <br>

Shot yourself a ruler at 45 degrees and see what the camera is really doing - that will tell the tale.</p>

 

[photomarche]

<p>Dan,<br /><br />I focused using live view autofocus. The focus point is the statue. I noticed the difference in sharpness looking into the fine details on the statue body. Other people in the house noticed this difference as well looking into the monitor. I performed other test all 70mm at f2.8, using also a different body ( the D7000) and there is a difference is sharpness between f2.8 and the same images stepped down 1 or 2 stops. If this behavior is expected when shooting wide open, as Peter post seems to suggest, I am fine with that.<br>

Gary, thanks for the advice on the ruler. <br /><br /><br /></p>

 

[elliot1]

<p><em>" I am pretty sure that virtually no lens is as sharp wide open as stopped down one or two stops"</em></p>

<p>Peter, you are correct but in the case of Nikon Pro glass, I have found these types of lenses are pretty much as sharp wide open as when stopped down - which is probably why they cost so much more than consumer rated lenses. My sample crops clearly illustrate this.</p>

<p> </p>

[Peter_in_PA]

<p>Elliot,</p>

<p>The problem is that is not what you said. You said "I have always found Nikon pro glass to be just as sharp wide open as when stopped down." That is incorrect and misleading.</p>

[elliot1]

<p>Peter, the bottom line is that I have found pro Nikon glass to be just as sharp wide open as when stopped down. I have found that to be the case based on tests I have done in the past with Nikon's 17-55m which I used when I shot DX, the 24-70mm as shown above (a quick test I did yesterday) and both versions of the 70-200mm. </p>

<p>I suspect the sharpness issues illustrated by the OP's example are a result of focus error as the large leaf in the front of the pot is in what appears to be in perfect focus in both shots but the statue is not which is what he says he focused on.</p>

<p>The bottom line is that I have never seen that much of a difference in sharpness with my lenses except when focus is incorrect.</p>

<p> </p>

[Peter_in_PA]

<p>Elliot writes </p>

 

<blockquote>

<p>Peter, the bottom line is that I have found pro Nikon glass to be just as sharp wide open as when stopped down.</p>

</blockquote>

<p>Elliot, I honestly don't mean to be insulting, but your testing methodology is therefore suspect or perhaps your tolerance for "sharp" is simply less than others, since I have yet to see a formal test of a Nikon lens where it was "just as sharp wide open as when stopped down".</p>

<p>That said, you are totally correct that many complaints regarding this issue are related to focus error and NOT to actual lens sharpness.</p>

[elliot1]

<p>Peter, I am not the only person in the form who has made this claim about the sharpness of Nikon's pro glass.</p>

<p>I am curious, what do you think is wrong with the crops I posted?</p>

<p>What do you think caused the OP's results and conclusion?</p>

[Peter_in_PA]

<p>Elliot,</p>

<p>Even <em><strong>your own test above</strong></em> (although doing a test like this with auto ISO on kind of obviates the results, too) shows a visible increase in sharpness (and related contrast) from f2.8 to f4, and yet you claim... again... </p>

 

<blockquote>

<p>Peter, the bottom line is that I have found pro Nikon glass to be <em><strong>just as sharp</strong></em> wide open as when stopped down. <em>(emphasis added)</em></p>

 

</blockquote>

<p>I say again, Elliot, that is categorically untrue, even when I look at your own test above. So... I am forced to conclude that either you can't see the difference, or you ignore it. The problem is that people come to this forum to get answers to questions (both right now and years in the future), and your posts on this topic end up being misleading for those folks.</p>