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Stonecherub Silver Member Nikonian since 03rd Jan 2011Mon 21-Nov-11 10:14 PM
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"Lens problems"


Tucson, US
          

I had a very unsatisfactory session in the field with my volcanoes last weekend and came to suspect my camera.

I ran some tests today on a parking garage with sharp edge detail in the blocks. It is about 70 m distance, scattered clouds, 11am Tucson time. ISO set to 1 EV under to reduce sensitivity.

The camera is a Nikon D5000 with 18-200 FS Nikor G II on a solid tripod mount These images are selections from the left, center, and right parts of the photos at various f stops and zoom levels of 18, 35 and 70mm. Clearly, the left side of the field is sharper than the center and that sharper than the right. Wide open the lens is a coke bottle bottom.

Is there anything I can do other than replacing the lens with something of a higher quality? If it is a matter of repair, where?

I have no idea whether there are nine files attached or not.


Visit my Nikonians gallery.

Attachment #1, (jpg file)

  

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Subject Author Message Date ID
Reply message RE: Lens problems
Cruch
22nd Nov 2011
1
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briantilley Moderator
22nd Nov 2011
3
Reply message RE: Lens problems
blw Moderator
22nd Nov 2011
2
Reply message RE: Lens problems
gkaiseril Gold Member
22nd Nov 2011
4
Reply message More on that lens problem
Stonecherub Silver Member
22nd Nov 2011
5
Reply message RE: More on that lens problem
Cruch
22nd Nov 2011
6
Reply message RE: More on that lens problem
Stonecherub Silver Member
22nd Nov 2011
7
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bclaff Silver Member
23rd Nov 2011
8
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Stonecherub Silver Member
23rd Nov 2011
9
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blw Moderator
23rd Nov 2011
10
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Stonecherub Silver Member
23rd Nov 2011
15
     Reply message RE: More on that lens problem
blw Moderator
24th Nov 2011
16
          Reply message RE: More on that lens problem
Stonecherub Silver Member
24th Nov 2011
18
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blw Moderator
23rd Nov 2011
11
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bclaff Silver Member
23rd Nov 2011
12
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Stonecherub Silver Member
23rd Nov 2011
13
          Reply message RE: More on that lens problem
bclaff Silver Member
23rd Nov 2011
14
Reply message RE: Lens problems
blw Moderator
24th Nov 2011
17
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blw Moderator
24th Nov 2011
19
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Stonecherub Silver Member
24th Nov 2011
20
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blw Moderator
24th Nov 2011
21

Cruch Registered since 22nd Nov 2011Tue 22-Nov-11 03:23 AM
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#1. "RE: Lens problems"
In response to Reply # 0


CA
          

I was told nine times out of ten this is a sensor alignment issue from the factory, not the actual lens. I heard it's most common with Canons.

  

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briantilley Moderator Deep knowledge of bodies and lens; high level photography skills Nikonian since 26th Jan 2003Tue 22-Nov-11 11:55 AM
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#3. "RE: Lens problems"
In response to Reply # 1


Paignton, GB
          

>I was told nine times out of ten this is a sensor alignment
>issue from the factory, not the actual lens. I heard it's most
>common with Canons.

We hear very little about sensor misalingment issues here, and I don't believe they are particularly common with other brands either.

But as (the other) Brian has suggested below, we really need more information before jumping to conclusions. There's no way to tell for sure from the single image posted what the problem might be.

Brian
Welsh Nikonian

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Tue 22-Nov-11 11:25 AM
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#2. "RE: Lens problems"
In response to Reply # 0


Richmond, US
          

This does look terrible, but there are a couple of things you need to check first.

- you referred to selections from left, center and right, but I see only one image here. You also mentioned 18, 35 and 70mm, again there appears to be something missing.

- how do did you focus this? Probably AF, but if so did you verify that it was locked in?

- It appears from the perspective that you were fairly parallel to the wall, but not quite. This can particularly important at some apertures, although 70m probably not too critical. But let's verify, first.

- how long was the exposure? Presumably nothing radical, but I can't tell. Particularly if it's a very long exposure, you could have thermal disturbance - particularly if there is 70m worth of asphalt between camera and subject, and especially if that asphalt is much warmer than the surrounding air. Clearly not a major factor at 1/2000th, but can contribute a surprising amount of softness to an image.

> I was told nine times out of ten this is a sensor alignment issue from the factory, not the actual lens. I heard it's most common with Canons.

The vast majority of the time that I've encountered something like this, the problem is a decentered element in a lens. That's virtually certain to be why the left and right are not the same. However, we need eliminate the possibility that the problem is simply focus, DOF, subject not parallel to the sensor, etc per the above before making such a conclusion. Given that you say that the lens is a coke bottle, it's a reasonable bet that something is wrong. The 18-200VR is not the sharpest lens available, but you weren't testing its weak point, and in the range you were using, it's far, far better than merely good, let alone coke bottle. I posted some samples here for reference. Safe to say that they are worlds sharper than what I see above.

I don't buy for a moment that the sensor is the problem. It could be, but since it is extremely difficult to get that wrong, and much easier to get other things wrong or broken, there are many other things to consider first.

I would try another lens, first. Just go down to a camera store and try a different lens on your camera. Any lens will do. You must use good technique to test - many but not all of the items are listed above. But if some other lens works better, I'd say that there is plenty of evidence that your lens is either defective or broken. I can't tell the difference between those - there are a variety of ways in which it could have arrived in good shape and become broken, some of which Nikon will handle under warranty (interior element came loose due to insufficient tightening of retainer) and some of which would not be (impact damage).

If another lens is no better, I would not suspect the sensor, but the lens mount. It is far easier to get that out of alignment than goofing up the sensor mounting. Obviously I have no way of knowing whether the one sample above is from the left (sharper) side of things or the right (blurry) side, but if it's the sharp side (consistent with "coke bottle") this indicates that something is pretty seriously out of whack, probably further than is reasonably possible with the sensor. (This is another reason I suspect the lens. There's a lot more room for error.) For the sensor to be this far off it would have to be missing by a pretty considerable margin - very possibly over 1mm - and if it's off by that far, it or the AA filter covering it will likely interfere with the shutter curtains. It is even hard to have the lens mount off by that far without having obvious impact damage, although it is possible if the lens mount is not securely fastened to the interior chassis.

-----

Bottom line, though, is that whatever it is, is severe, and this almost certainly warrants a trip to Nikon.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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gkaiseril Gold Member Nikonian since 28th Oct 2005Tue 22-Nov-11 03:20 PM
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#4. "RE: Lens problems"
In response to Reply # 0
Tue 22-Nov-11 03:50 PM by gkaiseril

Chicago, US
          

Were any of the manual/auto focus switches set to manual?

Did the in focus light indicate that the chosen focus point was in focus?

Was the shutter release set to take a image even if focus has not been achieved?

The image appears dark and the focusing system may not have been able to achieve focus.

Please complete you user profile.

George
My Nikonian Galleries

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Tue 22-Nov-11 05:52 PM
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#5. "More on that lens problem"
In response to Reply # 0


Tucson, US
          

Only one fuzzy image got posted with my original submission so I put them all on a web page and uploaded it in the troubleshooting area of my website:

http://pinacate.org/testarea/lens.html

A better explanation of the test is on that page. Please post your comments here rather than on the website.

I will be in NYC the last two weeks of December, perhaps somebody can recommend a repair shop there. Surely, I can get a Nikon fixed in the photo capitol of the World.

Visit my Nikonians gallery.

  

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Cruch Registered since 22nd Nov 2011Tue 22-Nov-11 08:29 PM
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#6. "RE: More on that lens problem"
In response to Reply # 5


CA
          

Oh seems you're having the same issue as me with my d5100 that I was just to post about.

We went to a wedding and about half of my wifes pictures were ruined because it was focusing on things in the background instead of the subject.

She was on f1.8 in S mode most of the night (dark banquette hall).

That same night I was using the Canon t3i with Sigma 17-50mm f2.8 and didn't have any of these problems.

I'll make a separate post about the issue..

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Tue 22-Nov-11 08:41 PM
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#7. "RE: More on that lens problem"
In response to Reply # 6


Tucson, US
          

This is a different issue. Yours sounds like you didn't pay attention to the little rectangle that shows the focus point. Been there, done that. I have several pictures of fuzzy gravestones with razor sharp background grass. Mine is a shift of focus across the picture area.

Visit my Nikonians gallery.

  

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bclaff Silver Member Awarded for multiple contributions for the Resources Nikonian since 26th Oct 2004Wed 23-Nov-11 01:04 AM
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#8. "RE: More on that lens problem"
In response to Reply # 5


Vancouver (WA USA not Canada), US
          

Daniel,

You say the camera was on a tripod (makes sense).
The metadata (Exif) was that VR was On; not a good idea on a tripod.
Also, what was AF Area Mode set to? If it was Auto then that could be a problem too.


Bill

Visit me at My site

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Wed 23-Nov-11 01:28 AM
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#9. "RE: More on that lens problem"
In response to Reply # 8


Tucson, US
          

AF was set to S. There is a single focus box that I can drive around the screen with the ring around OK.

I can't imagine that VR had anything to do with this problem. The left to right sharpness problem is there on the hand held images, too.

I'm somewhat limited in what I can do. One of the physical capabilities that age has robbed is my balance. Hopping from rock to rock is no longer possible. I depend on that walking stick to move across the lava. Therefore, I cannot easily carry the stick and the camera mounted on its tripod, the tripod is in my pack and the camera on a strap around my neck.

Visit my Nikonians gallery.

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Wed 23-Nov-11 07:32 AM
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#10. "RE: More on that lens problem"
In response to Reply # 5


Richmond, US
          

I don't have time to go through everything right now, but I will say that the picture of you in front of the lava is clearly not softness but a missed focus opportunity. You are very fuzzy, but the lava behind you is in decent focus.

My advice on this one is to load the original file into ViewNX and have it show you the focus point. I'll bet that it's not where you think it is. Assuming that the crop of you is from the first file, this isn't a "simple" matter of back focus - what is in focus is apparently 10 meters behind you. Back focus of that magnitude would be out of specification by perhaps 100x.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Wed 23-Nov-11 05:02 PM
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#15. "RE: More on that lens problem"
In response to Reply # 10


Tucson, US
          

I downloaded and installed ViewNX2 and see that the focus point in my picture was the top edge of the bomb and the rubble in the background is semi-sharp. But other images shot that day are fuzzy.

I signed up for picturetown and posted the images there full size. Look for "stonecherub."

Visit my Nikonians gallery.

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Thu 24-Nov-11 09:08 AM
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#16. "RE: More on that lens problem"
In response to Reply # 15


Richmond, US
          

> Look for "stonecherub."

After a frustrating half an hour, I have reluctantly signed up for picturetown. I see absolutely no way for me to look at any files belonging to anyone else. It's all about me uploading my data to them. How do I "look for" your files?

> the focus point in my picture was the top edge of the bomb

That makes sense, actually, since I think that's the center of the frame.

> But other images shot that day are fuzzy.

But did you check their focus points?

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Thu 24-Nov-11 01:26 PM
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#18. "RE: More on that lens problem"
In response to Reply # 16


Tucson, US
          

Brian, I really appreciate your attempts to help me. You recommended ViewNX and i got it. That had a link to "picturetown" and I mistakenly(?) assumed it was a place to publicly post images. Maybe not.

Send your e-mail address to stonecherub@gmail.com and I will use one of those big file transfer services to send you a selection of full-sized images.

I photographed hundreds of colonial gravestones last summer, looked at the downloaded images casually, and intended to get to them this winter. The volcanoes got in the way. I noticed with the gravestones a difference in sharpness across the image.

I agree that much of the problem last weekend was my carelessness. The light Saturday was bad and I took too many pictures hand holding the camera at shutter speeds less than 1/200. But, Friday pictures in full sun at much higher shutter speeds aren't much better.

Visit my Nikonians gallery.

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Wed 23-Nov-11 07:39 AM
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#11. "RE: More on that lens problem"
In response to Reply # 5


Richmond, US
          

Rather than the clips, it would be better to simply post the original file in its entirety. That way it's easier to see the relationships, and furthermore the EXIF data would be available.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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bclaff Silver Member Awarded for multiple contributions for the Resources Nikonian since 26th Oct 2004Wed 23-Nov-11 03:39 PM
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#12. "RE: More on that lens problem"
In response to Reply # 11


Vancouver (WA USA not Canada), US
          

Brian,

it would be better to simply post the original file in its entirety.

Given the resolution and size constraints that isn't possible, is it?

Perhaps something like yoursendit.com or email to myself or you?

Regards,
Bill

Visit me at My site

  

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Wed 23-Nov-11 03:47 PM
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#13. "RE: More on that lens problem"
In response to Reply # 11


Tucson, US
          

I found a beta called Filemail that I can use for free. I am going to pack up some images from the bad photo day and the Tucson garage. I shot nef & jpg and converted the nef to dng as part of my workflow. I noticed that the jpg files lack many EXIF values.

Visit my Nikonians gallery.

  

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bclaff Silver Member Awarded for multiple contributions for the Resources Nikonian since 26th Oct 2004Wed 23-Nov-11 04:50 PM
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#14. "RE: More on that lens problem"
In response to Reply # 13


Vancouver (WA USA not Canada), US
          

Daniel,

I noticed that the jpg files lack many EXIF values.

FWIW, the original JPG files, straight out of the camera contain the same information as the NEF files.
But once you've had the file into a program and saved it back out; all bets are off.
Also, FWIW, a transfer program, such as Nikon Transfer, also changes the file; the resulting file is not IMO an original.

Regards,
Bill

Visit me at My site

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Thu 24-Nov-11 12:58 PM
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#17. "RE: Lens problems"
In response to Reply # 0
Thu 24-Nov-11 01:00 PM by blw

Richmond, US
          

I don't have enough patience to wait for some other mechanism for getting better data, so I'm just going to comment on what I see here.

First, the fact that VR is enabled on a tripod is significant. It demonstrably softens images in this configuration. Also, the crops are all different sizes, so it's really hard for me to get a gauge on the relative situations.

The 18mm images are hard to analyze. They do look terrible, well beyond what I think should happen in this circumstance - even with VR on a tripod, although frankly I don't have a lot of experience with that non-recommended configuration to know for sure.

The 70mm is easier to deal with, since some of the aperture information is provided. The target should be parallel to the sensor. It is clearly not so, but judging by the angles, that difference is pretty minor. Assuming a focus distance of 70m = 200 feet the relatively small apparent error should be well within the DOF associated with the focus distance and aperture. So something is not right. Moreover, as you observe, the left and right sides do not appear to be equal. As noted above it's really hard for me to judge just how far out they are as the crops are all different sizes.

I would say that something is probably wrong with your lens, although I anyway would not send it off just yet for repair. However, from the limited information available, I'd also say that there is an interesting amount of user error also, not necessarily in the same image. The image of you with the bomb is definitely not demonstrating a lens error (even if it may be present).

I'll be back in a while with some additional info.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Thu 24-Nov-11 02:02 PM
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#19. "RE: Lens problems"
In response to Reply # 0


Richmond, US
          

I did a similar experiment, largely because I feel that doing tests such as this are very difficult to get right. They seem simple, but there are many details that can trip up the unwary, and even someone with some experience can easily make a number of mistakes. I regard myself as only barely past the novice stage at doing tests. There is a LOT that I don't know. Still, I think that results, with commentary below are likely useful to others.

I used my D2x as I don't have a D5100; it's the closest I have. The lens is the 18-200VR. I used a Gitzo 1348 tripod, a remote release, and mirror up. The remote is fairly important, especially at the shutter speeds I was using (about 1/40th), and likely Mup was useful too. I made sure to lock down the head.

As I was starting, I realized that I wasn't perfectly square to the brick wall in question, so I got out a tape measure to verify that I was within about an inch of equidistant - the point being that the focus distances to left and right would be equal, by having the sensor as parallel as reasonably achievable to the presumably flat subject. (Visual inspection of the wall suggests that it is indeed pretty flat.) This was particularly pertinent to my situation as I don't have a large wall available, so I had to use a much smaller one - and at much shorter distance. At 14 feet, an error of two inches is of far more consequence than at a focus distance of 200 feet.

On the other hand, I also did not have 200 feet of Tuscon asphalt between the subject and camera. Historical weather indicates that the weather was sunny the day you did the test images, so there's a real possibility that thermal disturbance contributed to the results. I'm not positive of the amount, and probably not a great deal, but it is definitely worth pondering in the absence of other data.

I took five frames at each focal length, to ensure that I didn't make some mistake on a single sample. In my case I did make one mistake, although it was on exposure and not focus. But had I not taken multiples I might have missed it.

I used a constant aperture (f/8 in this case), chosen to eliminate variability, get a reasonable DOF, and also because that's a better aperture on this lens.

In my case I did use AF. On a camera with LiveView, I would have used and mode and the focus zoom to ensure that focus was perfect. My D2x doesn't have LiveView, so I just did the best I could. I did ensure that there was a high contrast dividing line squarely in the AF target, which is relatively straightforward on a D2x as the targets are very large. This is particularly true on a brick wall.

As I started to change the focal length from 18mm to 35mm, I noticed that the camera was NOT in fact fully parallel to the subject! Yes, I had measured the distances already! What I didn't do was to level the camera. So I got out my hot shoe bubble level and leveled the camera that way. I am presuming that the wall was approximately straight up and down; I didn't have the patience to check it with a plumb bomb, which I would have done had I suspected a lens element decentered in the up/down direction, or a bent lens mount. (I've had both in my career, both due to impact damage.) After I leveled the camera, I reshot all of the images at 18mm, then did 35mm and 70mm.

I was careful to refocus after changing focal lengths, by manually turning the focusing ring to an obviously out of focus, then use the AF to acquire focus for the new focal length. This lens, like virtually all modern zoom lenses, is a varifocal design. That means that if you are in focus at one focal length, and then zoom, you will almost certainly need to refocus at the new focal length, even if the rest of the setup - tripod, subject, etc - are entirely immobile. This was not the case many years ago, when most zooms were parfocal, but certainly the 18-200VR is not. (My pro zooms aren't, either. At least, not the AF ones.)

Here are the results. All of the small crops are exactly 300x300 pixels. While they are not pixel-exactly corresponding, they are pretty close. In other words, I didn't pull the bottom right and the middle left of the images.


18mm, whole frame, then left, right and center:














Next, 35mm. Same order:














Then 70mm:














And finally, for bonus points, 200mm:













----

These show minimal differences left to right, clearly much less than your images appear to demonstrate. I would guess that I took a number of steps in the testing process that you did not. Finally, here's what happened after I shot the 200mm. I zoomed back to 18mm and did not refocus. In other words, I made the parfocal error:



The left crop is from the 18mm image I used above, which was focused properly. The right crop was from the parfocal error image. This looks a lot more like your results at 18mm.

Per my above comments, my analysis of your single images seems to suggest either a decentered element or a bent lens mount, but before accepting that conclusion, I would go back and do the experiment with at least as much rigor as I used here.

I'm sure others who are more knowledgeable than I will point out my methodology errors, but I feel pretty confident that even so my results are more consistent and repeatable than typically found on the Internet.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

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Stonecherub Silver Member Nikonian since 03rd Jan 2011Thu 24-Nov-11 03:11 PM
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#20. "RE: Lens problems"
In response to Reply # 19


Tucson, US
          

OK, I will re-shoot the test using bricks. The University is entirely brick and I can probably find some place where I can establish the lens axis normal to a wall. Most likely tomorrow.

Visit my Nikonians gallery.

  

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blw Moderator Awarded for his high level of expertise in various areas Nikonian since 18th Jun 2004Thu 24-Nov-11 03:31 PM
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#21. "RE: Lens problems"
In response to Reply # 20


Richmond, US
          

Bricks aren't really the point, though - it's about eliminating possible sources of error, such as focus distances, AF problems, VR issues, sharpness techniques, etc. All of those (plus, I'm sure, others) are relevant and need to be accounted for in the test. Otherwise the test has no validity.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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