Sigma 50-500mm OS Autofocus problems

About 8 months ago I purchased a new Sigma 50-500mm f/4.5-6.3 DG OS HSM APO lens (that’s a mouthful). I bought it during the final heydays of Microsoft ‘s Bing Cash Back program, when they were giving away cash on pretty much anything you could find in a search engine. Ah, the good ‘ol days. I never actually opened the box because at the time I wasn’t sure whether I’d be using Canon or Nikon for my long focal length shooting and have since decided on Canon for the long stuff.

I finally got around to listing the lens for sale on fredmiranda.com and found a willing buyer who only asked that I test the lens out first to make sure it doesn’t suffer from any Sigma-esce focusing problems. Smart move. I mounted the lens on my D7000 and did some IQ tests first. Images looked great – sharp at 500mm @ f/6.3, sharper still at f/8.0. Not a light speed demon by any means but for the price and focal range I consider the Sigma a good deal. Then I did my focus tests and uh oh, the lens started bucking like a donkey at 200mm. Either it would refuse to focus, meaning nothing happened when I pressed the back-button focus on my D7000, or the lens would do a few jerks to humor me and then just sit there like a sad, graphite-colored puppy. For the few times it actually attempted to focus it would take about a second to shift through its non-focal-distance-limiter-support range (in other words, no focal length limiter switch like on Canon/Nikon telephotos) and then give me that comforting focus confirmation “beep” on my D7000, only to be greeted by great bokeh that covered the entire range of frame, including the subject I was attempting to focus on. In other words, it was completely out of focus. Same results at 300mm and 400mm, but better at 500mm.

Needless to say the sale is off, at least until I get the lens fixed. To Sigma’s credit I looked up my serial number and it does fall within the range of recalled copies for the 50-500mm OS line, a recall that was proactively announced by Sigma all the way back in July 2010. So Sigma knows about the issues and got in front of the problem so it’s up to me to do my part and send the lens in for an AF motor tuneup. I’ll reevaluate the AF when it arrives back and post my results. In the meantime here’s a video showing the AF problems I observed.

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7 Responses to Sigma 50-500mm OS Autofocus problems

  1. Robert Thompson says:

    Hi,

    I have the same problem how do I find out about the recall serial number?

  2. Adam says:

    Hi Robert,

    You can get the serial number range here:
    http://www.flickr.com/groups/sigma_lenses/discuss/72157624331867633/

    • Robert Thompson says:

      thanks Adam,

      my lens is not in the the range of the recall but It does have Af problems at all focal lengths!

      do you know where I could get this fixed as I want to sell the lens

  3. Robert H. says:

    I have had my 50-500mm for just short of three years and really still love such with my Nikon D300. For the first time just three nights ago I took numerous photos of the rising full moon. Every photo was taken tripod mounted with various shutter speeds and aperatures. Obtained many excellent manual exposures but not one single one of them are sharp focus. I took moon photos with a leased identical lens over three years ago and obtained some crystal sharp moon images. Unfortunately not now. Any suggestions or do I just need to have such repaired. I’m down in south Florida. Thanks

    • Adam says:

      Hi Robert,

      I received my copy back from Sigma last week. They did the recall mods on it (replaced the lens barrel) but they were unable to reproduce the focusing problems. I still have the same focusing issues with the indoor lighting I originally tested it with, but when I took the lens outside with my D7000 it nailed focus nearly 100% of the time. It appears the issue I have is in limited light situations, or perhaps a combination of the LV and light temperature. It sounds like your D300+lens has gone out of calibration; I’ve never had that happen to me but I’ve read it happens rather frequently for pro’s who use their cameras heavily (these are mechanical elements). I’d suggest checking if you can get the lens within acceptable focus using your D300’s AF tune. If the calibration is off beyond what AF tune can accommodate then yeah, sounds like you’ll need to sends the lens to Sigma. Some people send both their camera+lens to Nikon for tuning/matching but I’m not sure Nikon would tune the camera to a 3rd-party lens.

      -adam

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