[Studor13]

I've had the 24-85mm f3.5-4.5 non VR for sometime and I always had a problem with it. First on the D300 and now on the D800. The problem is that the center is not at all sharp but the corners are OK.



The lens is not expensive but I just wanted it to be OK, so I took it in to have the lens re-calibrated. The Slovenian Nikon dealer instead of doing what I wanted did an auto focus adjustment and charged me 50 euros. The lens is no better than how it was. I told them that the D300 and D800 have the AF Fine Tune and therefore there was no point doing what they did.



I was then offered an optical re-alignment in Germany. The lens was sent and now Nikon Germany says that the lens is within factory specification. The lens will now be sent back.



So, what exactly is "Within factory specification"? And more importantly, do you think that there is a problem with my lens, or am I just being difficult?







Original files:

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f4.jpg"]24-85 at 24mm and f4[/url]

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f8.jpg"]24-85 at 24mm and f8[/url]

[url="http://www.studor13.si/music/photos/PZ/16-35-at-f4.jpg"]16-35 at 24mm and f4[/url]

[joachim]

[quote name='Studor13' timestamp='1361005194' post='21947']

I've had the 24-85mm f3.5-4.5 non VR for sometime and I always had a problem with it. First on the D300 and now on the D800. The problem is that the center is not at all sharp but the corners are OK.



The lens is not expensive but I just wanted it to be OK, so I took it in to have the lens re-calibrated. The Slovenian Nikon dealer instead of doing what I wanted did an auto focus adjustment and charged me 50 euros. The lens is no better than how it was. I told them that the D300 and D800 have the AF Fine Tune and therefore there was no point doing what they did.



I was then offered an optical re-alignment in Germany. The lens was sent and now Nikon Germany says that the lens is within factory specification. The lens will now be sent back.



So, what exactly is "Within factory specification"? And more importantly, do you think that there is a problem with my lens, or am I just being difficult?







Original files:

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f4.jpg"]24-85 at 24mm and f4[/url]

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f8.jpg"]24-85 at 24mm and f8[/url]

[url="http://www.studor13.si/music/photos/PZ/16-35-at-f4.jpg"]16-35 at 24mm and f4[/url]

[/quote]



Looking at your files (24mm f/8 24-85) I am wondering whether your sample shoots for that lens a mis-focused. It seems quite sharp outside the window. Look at the detail of the yellow caterpillar/farming machine. Not sure where the 24 f/4 shoot of that lens is in focus, but even for that, detail gets better behind the juice box.



You didn't write what camera you used. If I understand it correctly the lens in question is from the "film-era". Does the camera have live-view?

[Kodachrome 25]

Looks like field curvature. How did you focus, on which part of the scene? Did you focus manually with live view at working aperture?



off topic: Did you ever manage to get those christmas euphorbiae to bloom again?



Cheers, Ralf

[Brightcolours]

[quote name='Kodachrome 25' timestamp='1361011535' post='21949']

Looks like field curvature. How did you focus, on which part of the scene? Did you focus manually with live view at working aperture?



off topic: Did you ever manage to get those christmas euphorbiae to bloom again?



Cheers, Ralf

[/quote]

Of course it looks like field curvature, but also like bad misfocusing (i am sure he focused in the center...).

[Guest]

[quote name='Studor13' timestamp='1361005194' post='21947']

I've had the 24-85mm f3.5-4.5 non VR for sometime and I always had a problem with it. First on the D300 and now on the D800. The problem is that the center is not at all sharp but the corners are OK.



The lens is not expensive but I just wanted it to be OK, so I took it in to have the lens re-calibrated. The Slovenian Nikon dealer instead of doing what I wanted did an auto focus adjustment and charged me 50 euros. The lens is no better than how it was. I told them that the D300 and D800 have the AF Fine Tune and therefore there was no point doing what they did.



I was then offered an optical re-alignment in Germany. The lens was sent and now Nikon Germany says that the lens is within factory specification. The lens will now be sent back.



So, what exactly is "Within factory specification"? And more importantly, do you think that there is a problem with my lens, or am I just being difficult?







Original files:

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f4.jpg"]24-85 at 24mm and f4[/url]

[url="http://www.studor13.si/music/photos/PZ/24-85-at-f8.jpg"]24-85 at 24mm and f8[/url]

[url="http://www.studor13.si/music/photos/PZ/16-35-at-f4.jpg"]16-35 at 24mm and f4[/url]

[/quote]



yes, like joachim said, it looks like misfocus. The yellowish wood just in front of the white wall panel, and the wall panel in the background at 24mm f4 looks actually quite sharp compared to the fuzzy text on the box, which really does not look sharp and simply could be out of focus.

[Studor13]

Well, I don't know anymore, but you need to look at the original files.



There are two bottles with the word Luna - one behind and one in front of the center of the target. The focus point is the word Fructal. You can see that Luna, whether in front or behind Fructal is equally in focus.



To me this says that the focus point is on the word Fructal.



The important thing to note is that the corners are definitely sharper than the center.



I have more than 30 Nikkors and this is the only lens where the center is softer than the corners.



Maybe I am expecting too much but to me the word Fructal - the center - is not just soft but plain wrong.



I can't see how at f8 the corners can be sharper than the center.





"Did you ever manage to get those christmas euphorbiae to bloom again".

I think they did but to be honest I didn't notice them there until you mentioned it. Maybe I should stop worrying about lenses and try to smell the flowers more.

[Guest]

[quote name='Studor13' timestamp='1361023249' post='21953']

Well, I don't know anymore, but you need to look at the original files.



There are two bottles with the word Luna - one behind and one in front of the center of the target. The focus point is the word Fructal. You can see that Luna, whether in front or behind Fructal is equally in focus.



To me this says that the focus point is on the word Fructal.



The important thing to note is that the corners are definitely sharper than the center.



I have more than 30 Nikkors and this is the only lens where the center is softer than the corners.



Maybe I am expecting too much but to me the word Fructal - the center - is not just soft but plain wrong.



I can't see how at f8 the corners can be sharper than the center.





"Did you ever manage to get those christmas euphorbiae to bloom again".

I think they did but to be honest I didn't notice them there until you mentioned it. Maybe I should stop worrying about lenses and try to smell the flowers more.

[/quote]



You can't use the two unsharp items (the luna bottles) to conclude it's got to be sharp in between them, it's too subjective. Try to find the sharpest line. I can't tell if you are perpendicular to the window or not, probably not, but the focal plane looks a bit like this:

In the bottom left corner of the left window, the red (box?) with white dots seems relatively sharp,

in the middle then: the backhandle of the wooden utensil holder behind the fructal juice and the window frame next to it (what I called wood panel before) seems to be sharp.

On the right: somewhere near or in front of the nektar juice (the napkin holder looks a bit sharp as well).

So, that's how the plane of focus seems to go to me with the focus behind the fruktal.

If you were relatively perpendicular to the window, is there perhaps some decentering / left-right asymmetry ?



BTW,

was this AF? the fructal box seems to be small enough that the AF could have picked the wooden holder in the back as target.

[Studor13]

"So, that's how the plane of focus seems to go to me with the focus behind the fruktal."



No, if that were the case the letters 8PK 64 just behind Fructal and to the right would be sharp - just as it is in the 16-35mm f4 image.



Look, the words Luna (front and back) and Fructal are plenty sharp in the 16-35mm file. And remember it is at f4! In the 24-85 files - f4 or f8 - nothing in the center is sharp.



But if you compare the relative sharpness of the words in the corners - left and right - of all three files, they are more or less the same , or at least acceptable.



Anyways, I would love Markus and/or Klaus to make a judgement.

[Brightcolours]

For now it looks to me like bad AF (making the center so unsharp) and field curvature (pulling the borders into focus).



Things are easily checked. Focus manual with live view on the center, and you will know how sharp the lens is at the center. If it is better, you know you have an AF problem with this lens on your camera.



Shoot a horizontal pattern at a 45 or so degree angle wide open. You will get to see the (if any) field curvature.

[PuxaVida]

Hi,



It looks like the f/8 shot is focused far beyond the windows (checking through the window, I can tell that the woden structures outside (in the center) are sharper than the inside center. And I guess f/4 shot is also misfocused but this time behind the fructal almost on the window. And I would say that this lens has a huge field curvature (sharp corners). These are my lucky guesses <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />/>...



I would try it with using the live view...



Serkan