First, some may say this is a duplicate of What should one look for when buying a used lens?, but I see it more as an update or complement for modern lenses.

I'm interested in buying a used modern lens with Image Stabilization, etc. What would you check when buying it?

The mentioned question refers to many good ideas when buying old, manual, lenses, but fails to give any ideas on how to check autofocus correctness, IS, aperture automation, and probably some other things I can't think of.

The origin of this question is due to an ad where it says “Works fine except for short focal lengths, where the aperture fails”. Wow, you start thinking of all combinations you should try when buying it, and you realize you need several days just to test it all.

So the question should resume to:

In addition to everything mentioned in What should one look for when buying a used lens?:

  • How do you test autofocus? At how many focal lengths? Do you need to check at different apertures, or one is fine?

  • How do you check IS? Trying improperly slow speeds to check it's doing its job?

  • How do you check aperture control? Do you check it at different focal lengths?

  • What else would you look for?

  • 2
    If a zoom lens "works fine except for short focal lengths, where the aperture fails" that's almost a sure sign a ribbon cable is cracked and will only get worse.
    – Michael C
    Apr 22, 2022 at 7:31
  • 1
    Several of the answers at the possible duplicate cover aperture operation in fairly good detail.
    – Michael C
    Apr 22, 2022 at 7:33
  • 1
    As for AF, it's pretty much the same for diagnosing any AF issue, whether you're evaluating a used lens for purchase or evaluating a lens you already own: How do I diagnose the source of focus problem in a camera?
    – Michael C
    Apr 22, 2022 at 8:28
  • 1
    Related: Is this lens decentered? one answer includes a link to Roger Cicala's excellent blog entry at lensrentals.com: How To Test a Lens.
    – Michael C
    Apr 22, 2022 at 8:35
  • 1
    @MichaelC Thanks, interesting. I'll read it attentively. Apr 22, 2022 at 8:43

1 Answer 1


Not to appear to be a shill for the used equipment brokers, I have nevertheless long ago confined all my lens purchases to the likes of KEH, MPB, and UsedPhotoPro. They all provide a short no-questions-asked return period, as well as at least a six month warranty period. During the warranty period they will repair or replace the item. You will pay slightly (and I do mean slightly) more than buying on eBay or Craigslist, but you'll get a realistic assessment of the item's condition, with notes about any known damage, and (usually) good pictures of same. I've purchased a half dozen or so lenses from the three aforementioned sellers over the past few years with a 100% satisfaction rate. I have also made a few private sales in the past that didn't turn out so well.

  • "You will pay slightly… more than buying on eBay…" Actually, that's not been my experience at all. evilBay is all over the place! You can generally trust the "brick-n-mortar" used camera stores to be competitive with each other fairly well. Also, I'm a HUGE FAN of KEH "UG"ly and "BGN" ratings. With some trepidation, I ordered an "UG" lens from KEH that was well under half the lowest "Sold" price on evilBay. It arrived in MINT CONDITION, but in a plastic bag, without case, nor either cap. I can buy a LOT of caps and cases for that money! May 30, 2022 at 18:58

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