Bad lens? Does this need to go for repairs?

Discussion in 'Nikon' started by paul_sokal___dallas__tx, Nov 19, 2005.

  1. I noticed when assembling a panorama taken with my 17-55mm, that the right side of the image is unusably soft at f2.8. I did some test images today mounted on a tripod with remote release, confirming my concerns. I'm attaching the full image of the test and a crop from the midline to where it softens. Is this the kind of performance others are getting or should I send it back? The left side seems okay. (This lens has been babied my me since I purchased it, BTW). I also repeated the test with my 18-70 and the cheapo kit lens did much better (of course that was at 18mm and f3.5, as opposed to 17mm and f 2.8).
    00EEyl-26568284.jpg
     
  2. The camera was not leveled properly, resulting in convergence. There is also a great deal of barrel distortion and vignetting in each corner. What camera was used? Filter?

    Is this really from the 17-55? Normalization issues aside, the performance is pretty bad. I wouldn't expect to use this lens for flat copy, but the results seems gross for a $1400 lens.
     
  3. What's all this talk about DX-sized glass being immune to vignetting?

    So much for full frame...
     
  4. This was shot at 17mm on a D2X without a filter. Like I said, the left side of the image is pretty sharp, but the right side is bad to my eye.
     
  5. ShunCheung

    ShunCheung Administrator

    Paul, my 17-55 DX has exactly that problem two months ago after an accidental drop in Paris. I had the lens on my D2X in a well padded Lowepro bag. Unfortunately, the strap came off the hook and the whole thing fell from waist level to the ground. I didn't notice any problem immediately but it turns out that the lens mount was bent.
    The symptom was that it could not focus to infinity at 17mm and the left side of the image was very sharp but the right side was out of focus. At 55mm the lens was fine. I compared images shot right before and after the drop and the difference was clear.

    Nikon at El Segundo (Los Angeles) charged me $130 to fix the mount.
     
  6. Hi Paul,

    First question - has this happened on other photos you've taken with the setup you're using? If not, then it is likely due to something in your setup this time.

    Is it repeatable? Meaning, does it happen every time with this setup?

    Was the paper totally flat? It could be caused by uneven paper, hence the different focal points. Was the camera/lens aimed perpendicular to the subject? Or, was it shifted off center on a diagonal?

    Are you are using autofocus? If you have the focus mode set on dynamic area, it might be the case that you accidentally hit the round selector on the back of the camera (D2x) which resulted in the focal point being moved to one of the left side "x's" which would result in such an image shown here.
     
  7. You are not serious right? About returning this lens?

    Shot wide open at 2.8 - perhaps try shooting at 3.5 for a proper comparison? The depth of field at any wide open aperture is very slim - you could be off by say 2mm off the paper plane & due to your distance the effect could be multiplied several times over. At what focal length of the zoom did you shoot? More details please.

    Fisrt off - I have only had experience with the 17-35 f/2.8 - I would only judge this event if the plane of the paper & the lens were in perfect alignment using scales & levels.

    Again - are you serious?

    If you are truly concerned about edge to edge tack sharp images maybe you need either a different lens or move up to 4x5 with movements.

    I would very much like to see this better image from the cheaper lens.

    As a last comment I would never use a zoom for panoramics & only use prime lenses that are considered to be fairly rectilinear.

    Please post this better image as I am anxious to see it.
     
  8. I just simply feel looking at the image that If you backed up 1 or 2 mm & moved left or right 1 or 2mm & recentered that at 2.8 it would be sharp.

    Did you crop the original shot at all?

    Just trying to be helpful & not an annoyance
     
  9. There are several variables here that could be confusing the problem. As has been
    suggested, camera needs to be perfectly perpendicular to copywork, work should be flat
    as possible, center of lens should be in center of subject. This is all difficult to do without
    a decent copystand. Also, no wide angle and particularly a wide zoom is going to perform
    well as a flat field copy lens. I have this same lens and have used it a few times on my
    copystand to photograph artwork that was really too large for my stand. I always try to
    back off a little, as the curvature is less pronounced in the center of the image. I have
    never used it at 17mm, thats a pretty wide lens for this type of work, try shooting at about
    35mm, back up if you can. I am not saying you can't use this lens for copywork, but it
    isn't really designed for it so expect some curvature and maybe some edge softness. That
    being said, I would expect the softness to be uniform, so I suspect, as has been
    mentioned, that you are not centered or perpendicular to the subject. I don't know if there
    is a better test than this, possibly try the same test of a larger smooth flat subject at a
    more reasonable distance, such as a monochromatic building at a bit of a distance. Make
    sure you are as perpendicular to the building as possible and level. Do not tilt the camera
    up or down, should be 90 degrees. If you still have a problem then maybe the lens needs
    to be examined. Good luck.
     
  10. In PS adding a grid I see that on the lower bottom left there are say 2 & 3/4's of the grid & on the lower righthand side 3 & 1/2 units. Topleft is about 2 & 1/4 of the grid & top right is about 2 & 3/4 of the grid.

    This describes to me that it is not truly dead centered.

    Not an easy thing to do getting all centered - perhaps if you were off centered to the right there might be concern of the lens on the left side perhaps.
     
  11. I should have posted this picture from the beginning I guess. This is the picture from the pano that clued me into the problem You can see that the center of the image is in focus but that the bushes to the right are much more out of focus, almost distorted, compared to the more distant background on the left side. This was shot at 26mm, f4, at 1/1000.
    00EF9N-26571884.jpg
     
  12. Crop of the right side
     
  13. This is a crop of the right side
    00EF9V-26572184.jpg
     
  14. Paul, I see your problem from the onset.

    You are trying to shoot a Dallas Morning News.

    Everyone knows that doing that always gives you fuzziness,
    unclarity, and questionable results. Oh sure, the center might be
    clear as a bell, but move to the left or right, and you're in trouble.
     
  15. No, no, no. The right is always in focus with the Dallas Morning News.
     
  16. Paul:

    I see a big difference now - thx for posting - I understand why you are concerned now.

    Not sure how I would proceed but I would at least provide images based on the last few. Maybe it's still in warranty? If not I would still pursue it with Nikon & not let it go.

    Hope all goes well.

    Let us know how it goes.

    Regards
     
  17. How were you set up for this last shot Paul?

    Focal length/f-stop, etc.... .
     
  18. 26mm, f4, 1/1000
     
  19. ShunCheung

    ShunCheung Administrator

    Paul, I am attaching an image shot with my 17-55mm DX shortly after it was dropped. This fountain image was shot with a D2X at ISO 100 at 17mm, f5.6 and 1/500 sec. To clearly show the problem, I am including a large version that is 1600 pixels across. Therefore it'll appear as a link. You can clearly see that the buildings in the background on the left side of the image are in focus but the ones on the right side are not. Again, after I dropped the camera bag, there was no apparent damage and I thought everything was ok since it is a rugged lens on a rugged body all inside a well padded bag. When Nikon repair service told me that my lens mount was bent and therefore it wasn't covered by the warranty, I was surprised. But inspecting images shot just before the drop clearly indicates that this problem didn't exist prior.
    00EFGV-26574684.jpg
     
  20. Thanks all. I guess it's headed back to B&H. It's grey market but still under their warranty.

    Paul
     
  21. If you haven't dropped your lens, I think the most probable cause is some lens elements that are not properly centered. I have a 24mm f2.8 with a mild case of this, unfortunatley I didn't discover it until 14 years after I purchased the lens (it mostly disappears at f4). Considering the purchase price of your lens, I would return it.

    PS, since you've now compared the cheap Kit Zoom to the 17-55, you can see why I have no interest at all in the more expensive lens. Nikon did a superb job with the Kit lens and I wish they had used the engineering resources wasted on the 17-55 on designing some DX primes. I's like to see a 12mm f4 and a 16mm f2.8.
     
  22. ShunCheung

    ShunCheung Administrator

    Sorry Scott, I cannot disagree more about the kit lens vs. the 17-55 DX. The 17-55 DX is a fixed f2.8 zoom that is excellent throughout it zoom range. It has a bit of barrel distortion at 17mm but that is slight. The kit lens is essentially a stop slower overall, has some very ugly mustache distortion at 18mm and has noticable vignetting wide open at 18mm also. For those whose budget is around $200 to $300, the 18-70 DX kits lens is an excellent deal. (The price different between the D70s only and with the kit lens is sometimes about $150 to $200, hence that is the net cost difference to the consumer.) For people who demand high quality and shoot indoors, low light conditions, the 17-55 DX is clearly superior.

    Paul, your lens mount could be slightly bent out of the factory or there could be a slight mis-alignment in the lens elements. B&H should be able to take care of that. I just checked B&H's web site and the price difference between the USA ($1250) and gray ($1200) versions is only $50. In that case I might just get the USA version.
     
  23. Just my 2 cents. I had a 17-55 DX and sold it on eBay because it's sharpness was always
    slightly disappointing to me. I replaced it with the slightly more expensive 28-70 f/2.8 and
    have been very pleased with that lens. I talked to a Nikon rep about it who admitted that he's
    heard other complaints about the 17-55 dx. If you can do without the wide end the 28-70 is
    a great lens. I do mostly portrait photography for my clients and so the 12-24 that would
    pick up the slack is still just on my wish list. :)
    -Chris
     
  24. I have a 18-70mm Nikon "kit lens" on my D70 that shows a similar problem confined mostly to the lower right corner. It is inconsistent, as I have gone through almost a year's worth of images and sometimes the softening doesn't occur. Also, at 18mm its always tack sharp across the field. So, because of the excellent performance at 18mm I hesitate to send the lens back (still under warrenty). I wouldn't want to get a different lens that didn't perform as well as this one at 18mm. I have a really sharp 28-300, a very sharp AF 50mm lens, a 55 Micro Nikkor, and a classic 105, so I really want to have a sharp wide angle in my bag. When I have photographed a flat textured wall on a tripod a couple of times the problem did not show up, even wide open, but it is quite evident in landscapes. I'm wondering if these zooms don't have internal lenses that can "float" around a bit and get slightly off axis during focusing. Yours looks pretty bad though and I wouldn't hesitate to send it in for repair or replacement.
     

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