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Heads together please guys...

tashley

Subscriber Member
I've have an issue. A long running, mindfeck of an issue, and before I take the next step I need some mental support, please, from the smart minds that hang around here.

On my original D800, my replacement D800 and my D800E, my 24-120 showed softness on the RHS only. It only started at 35mm and longer, but was clearly visible at F5.6 and wider and was still there even at F8. It seemed to come and go a bit, but was generally most always there. I thought it was decentered, or maybe not VR 'parking' properly.

I sent it off three times to get fixed and on the third try, spoke to Nikon in some detail about it. They insisted that there was no problem that they could see and though I provided files to demonstrate it, they just couldn't replicate it. So they said, maybe it's your camera's mount that's a bit off... and I replied that none of my other lenses in any focal length (spanning 14-200 and with about ten candidates including the Tammy 24-70 and Nikon 70-200) had the problem, but that this 24-120 lens had demonstrated the problem on three different bodies before the first fix (I now only have the D800E).

So NPS sent me a loaner lens and I tested it on my D800. The file, at 50% size, is linked here.
It clearly shows the issue.

So, process of elimination:

* My copy was bad on three bodies but Nikon can't see it in tests
* My body doesn't show this behaviour with any other lens
* My body does show this problem with the NPS loaner


I'm not seeing any elimination here.

Best guess is that the specifics of the zoom and focus internals of this particular design are picking up a mount misalignment on my camera that doesn't show with any other lens, and that this also showed on my other early bodies because early manufacturing had an issue that is now sorted. Either that or Nikon service are not testing the lens on a D800, and there is some natural dis-affinity between the designs of the 24-120 and the D900

HELP!
 

fotom

New member
Wow, that looks like a real big problem... :eek:

I have never seen something like that before. Have you activated CA and lens correction in the menu of the D800? But I don´t have an idea if that will have an effect when shot in RAW.
 

fotom

New member
And, do you see anything when looking into the lens? There must be a bubble in the front lens...
 

tashley

Subscriber Member
@ lens corrections in menus - I haven't because I only shoot RAW but that's not the source of the problem, as the asymmetrical nature of the defocus shows :-(
@ bubble, not that either: the NPS loaner lens (theirs are well checked on general) shows the same thing.

But thanks for thinking on it - this will take many heads I fear!
 

Mr.Gale

Member
"It seemed to come and go a bit, but was generally most always there."
At the same focal length and aperture? If it is a mount alignment problem I would think it would always be there.
 

tashley

Subscriber Member
"It seemed to come and go a bit, but was generally most always there."
At the same focal length and aperture? If it is a mount alignment problem I would think it would always be there.
that's part of the great mystery - it has appeared worse at different focal lengths after different 'fixes'. In general, if you peep hard, you can just see it at 24 and 28mm but it's nothing to make a fuss about. It starts to be intrusive to 'normal' print size at 35mm but, after the most recent fix, my copy was just acceptable at 35mm but was now pretty poor at 50mm even at F8, whereas historically, you could just squeeze a reasonable shot at F8 and 50mm and it was from 70 onwards that nothing worked. The loaner I shot literally three frames before leaving on a trip to see if it was ok, all at 35mm, one of them posted above, and it was such an obvious 'no' that I left the whole kit behind!

I have never seen anything like it. I think it is probably as I postulated in the OP, but that very small differences in focus distance relative to the scene can push over the border of acceptability one way or the other...
 

AreBee

Member
Tashley,

So, process of elimination:

* My copy was bad on three bodies but Nikon can't see it in tests
* My body doesn't show this behaviour with any other lens
* My body does show this problem with the NPS loaner


I'm not seeing any elimination here.
Answer: Nikon are not as rigorous in their testing as you are, and you happen to have been loaned a lens that also is a dud.

Seriously, I can't think what the problem may be. I can't imagine why Nikon are unable to find an issue that to you is quite obvious. I would, however, note that two lenses out of however many thousand have been manufactured represents a statistically insignificant sample. I also would suggest the following: send Nikon the body and lens.
 

tashley

Subscriber Member
Tashley,



Answer: Nikon are not as rigorous in their testing as you are, and you happen to have been loaned a lens that also is a dud.

Seriously, I can't think what the problem may be. I can't imagine why Nikon are unable to find an issue that to you is quite obvious. I would, however, note that two lenses out of however many thousand have been manufactured represents a statistically insignificant sample. I also would suggest the following as a way to eliminate Nikon as less rigorous as you: send them the body and lens.
Indeed, that's what's up next: I have just found with Nikon service that unless you are very clear about what's wrong and what the parameters are, they try half-heartedly to re-invent your wheel and then give up when it doesn't turn first time - so I want them to have as much info and hypothesis as possible. Also of course, I want to cover my own dumb @rse in case this is something obvious that I am not getting!
 

ptomsu

Workshop Member
I had similar experiences with Nikon Service with my 1.4/85, which showed abnormal high CA on my D7000. Sending it first to Nikon Austria did not help, same with Nikon Germany. They tested it and sent it back saying all is within normal conditions - I even got a test certificate, stating the lens is within limits.

Now the problem is still the same on my D800E and this is one of the reasons I am almost never using this lens. I know that the 1.4/85 has CA, as every fast lens will show, but never in that order of magnitude.

I remember a 1:2.8/180 APO Leica, which showed the same on my DMR, but sending it back to Solms completely fixed the problem. They had to adjust a lens element.

I am sure the same would work for my 1.4/85 Nikkor, but no one at Nikon Services does obviously care (or can care).

I used to have a 1.2/85 Canon which not at all showed this issue on the 5D2. And this lens is even brighter.

This is really very bad news, as it shows that quality control and measurement and fine adjustment at Nikon is not up to the level their camera bodies demand today. And to make it even worse is that the 1.4/85 Nikkor is a pro lens and pretty expensive too.

Not sure what I will do in the future. For now I do have to stay with Nikon as I need my D800E and lenses for some near term projects, but long term I might go a different route. Not sure either if Canon Service would be better :confused:
 

ptomsu

Workshop Member
Tashley,



Answer: Nikon are not as rigorous in their testing as you are, and you happen to have been loaned a lens that also is a dud.

Seriously, I can't think what the problem may be. I can't imagine why Nikon are unable to find an issue that to you is quite obvious. I would, however, note that two lenses out of however many thousand have been manufactured represents a statistically insignificant sample. I also would suggest the following: send Nikon the body and lens.
Question is ... why can Leica deal with such issues and solve them and Nikon can't???
 

Guy Mancuso

Administrator, Instructor
You really cant compare Leica and Nikon. Nikon makes a vastly huge amount of product compared to leica by the millions. If Nikon runs into a issue it affects many until the issue is caught . Leica it maybe a few hundred until a issue is realized. Lets say its comparing a full bottle of aspirin to like 2 sitting on the table. Leica is not the best for service just ask my two M8s that sat in Germany for months on end.

To the issue at hand. To me it sounds like a lens element that moves at a certain focal length or lets say pops out of spec. Also my bet is even there loaner lens and given you bought that lens maybe early on in a production run or at a certain time in a production run that they both could be showing the same issue. Now if you look at serial numbers they could be within a certain time of each other but we need to remember it could even be thousands apart as they produces a ton of these lenses. Not sure there loaner is even in spec. and probably not as loaners are typically returns or demo units. We can only guess here since we do not have this on a optical bench to test. But I'm leaning to a element that pops when you zoom to a certain focal length. When zooming elements change there position within the tube or shell.
 

ptomsu

Workshop Member
You really cant compare Leica and Nikon. Nikon makes a vastly huge amount of product compared to leica by the millions. If Nikon runs into a issue it affects many until the issue is caught . Leica it maybe a few hundred until a issue is realized. Lets say its comparing a full bottle of aspirin to like 2 sitting on the table. Leica is not the best for service just ask my two M8s that sat in Germany for months on end.

To the issue at hand. To me it sounds like a lens element that moves at a certain focal length or lets say pops out of spec. Also my bet is even there loaner lens and given you bought that lens maybe early on in a production run or at a certain time in a production run that they both could be showing the same issue. Now if you look at serial numbers they could be within a certain time of each other but we need to remember it could even be thousands apart as they produces a ton of these lenses. Not sure there loaner is even in spec. and probably not as loaners are typically returns or demo units. We can only guess here since we do not have this on a optical bench to test. But I'm leaning to a element that pops when you zoom to a certain focal length. When zooming elements change there position within the tube or shell.
I agree you cannot compare Leica and Nikon, but if we are talking about pro level glass from Nikon and Nikon service, then I expect Nikon to be able to correct vast abnormalities or at least replace the lens. Otherwise how can one really exploit the advantages of a high end system?

Also what worries me is the unprofessional access to their service and the inability to not be able to talk to them (their service interface) directly in order to describe the issue and help them understand better what you are looking for.

As I said I am not sure if Canon would be better ....
 

Steen

Senior Subscriber Member
(...) Also what worries me is the unprofessional access to their service and the inability to not be able to talk to them (their service interface) directly in order to describe the issue and help them understand better what you are looking for. (...)

:confused:

I just jump on my bicycle and go and have a talk face to face with the Nikon service person that will repair or adjust my Nikon camera and / or lenses.
While my M8 camera and M lenses I had to pack carefully and ship to Leica.

So I think it depends a lot on where we are located and I think we should simply give up generalizing about specific brands and their products and service.
It always depends.
 

tashley

Subscriber Member
:confused:

I just jump on my bicycle and go and have a talk face to face with the Nikon service person that will repair or adjust my Nikon camera and / or lenses.
While my M8 camera and M lenses I had to pack carefully and ship to Leica.
Can I come and live with your for a few months?
:D
 

Shashin

Well-known member
They could be testing the lens on an optical bench. If the lens comes within manufacturing tolerance, then it will pass. It is not really feasible to take a lens apart and tinker with the elements--the design does not allow for that. Nikon is between a rock and a hard place--they need to provide very good optics at reasonable prices (I wonder what Leica would charge) and that is a fine balance to keep. At some point the consumers is going to have to decide if that lens is for them--quality is subjective and if your expectations are very high, it is hard to meet. And to be honest, a 24-120 zoom is hard to make. It should be no surprise that other lenses will do better. The cost goes into just trying to make that zoom range work. To make it work perfectly would make the lens too expensive.
 

Guy Mancuso

Administrator, Instructor
Optics: 17 elements in 13 groups. The older sibling has a 15/13 design. Flares and ghosts can result from too many air/glass-surfaces and Nikon has added Nano-coating to reduce this. We'll see in my test how well this works. The cross-section shows three aspherical and two ED-glass elements. [+]


Thats a pretty complicated design for sure.
 

Shashin

Well-known member
And then consider those groups have to move while changing focal length and focus. And to maintain those distances becomes tricky. And IF lenses focus by changing focal length. The fact it works at all is a minor miracle.
 

jonoslack

Active member
1. * My copy was bad on three bodies but Nikon can't see it in tests
2. * My body doesn't show this behaviour with any other lens
3. * My body does show this problem with the NPS loaner


I'm not seeing any elimination here.
Eliminate this:
1. * My copy was bad on three bodies but Nikon can't see it in tests

I'm convinced Nikon have no idea about your kind of attention to detail:

I once took 5 copies of the 17-55 lens back to a big dealer in Cambridge - all with proper documentation showing a similar problem (soft side in the middle of the range). They dutifully change the lens for a new one, without complaining.

After a while I asked them if they'd had a lot of problems with this lens - He told me he'd never had one back faulty before . . and then, after a pause said that he almost never got faulty lenses on the basis of optical problems . . .much less than one a year.

I had a similar problem with the Pentax 16-50 D* lens last year - I had 3 copies - all which were soft between 35 and 50 - after 3 I gave up and sold all the Pentax kit I was so irritated. . . . . again Warehouse express (a big company) said they had seen no other problems.

The point about this, is that if you make 10,000 lenses, and 5 come back with complaints about their optical quality, a quick cost/benefit basis will tell you not to bother to try any harder: simple as that.

So you'll get no help from Nikon (although they'll probably happily keep on changing kit for you . . . and selling yours back as refurbished).

I'd say the likelihood of them seriously trying to reproduce the problem is very small (why bother if the lens is 'within specifications' and they aren't going to do something about it).

Which means that there is clearly a problem with both your lens and the loaner

So, the solution to the conundrum is simple - Nikon aren't looking properly or don't care. 2 and 3 then make perfect sense.

You could keep changing lenses if you want (I did get a decent 17-55 in the end).

All the best
 
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