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Tamron 17-50 artifacts and tight hood.

Discussion in 'Lens Matters' started by DaveG40, Sep 17, 2017.

  1. DaveG40

    DaveG40 Well-Known Member

    Evening All, I've recently bought the Tamron 17-50 f2.8 in Sony Alpha Mount off of ebay, I paid a good price (£110), which included postage.

    To look at the lens looks mint and testing over the weekend has been as expected; exceptional, and a very close match for the Sony 16-50 which I've had in the past. Optically all the photo's shot with it have been as expected, and yes I'm very pleased with the results, and the focusing is fast and assured however; the lens hood was very stiff when parked or fitted, lens cleaner around the bayonet fixings did drastically improve the play however things seems to be tightening again, but the worst thing and the reason I'm writing are the half a dozen or so artifacts on the inside of the rear element, it doesn't look like fungus and being on the inside, and they don't seem to affect Image I.Q at all. I'm at a bit of a loss as to what it is, how to remove them (if possible), and given that I'm within the time frame of returning the lens; would like to know if it's likely to get worse and more importantly if it's going to degrade IQ.
    It's unlikely, but not impossible that I'd get another 17-50 f2.8 for the same or less and it's definitely producing the goods, but is it a keeper or go-er ?.
    Any info or advice would be greatly appreciated, as to what the artifacts are and the best way off freeing up the lens hood is.

    Attached Files:

  2. PeteRob

    PeteRob Well-Known Member

    Horses for courses. If you'd inspected this in a shop what would you have done? Lenses do get dust in, though I've nor seen the like inside (outside yes) the rear most element but if you can't see it in the image so what does it matter? It sounds from your first description that the lens does everything you want and fits its as sold description.

    If you degrease the lens barrel then you will make a tight lens hood harder to tighten. I was embarrassed to find that on the last lens I bought the hood clipped into final position. I nearly destroyed it trying to get it off before I noticed the release. Never seen that one before.
  3. nimbus

    nimbus Well-Known Member

    Looking at your picture it would appear that those are marks on the rear glass itself. They certainly are not fungus, even if they are within. Whatever they are unlikely to become worse and if they are not posing a problem, so if you are happy with it otherwise, perhaps it should be a case of don't worry about it, they are in the place where they are least likely to affect results. Try cleaning rear glass carefully, if they remain you could always lean on the seller for a part refund if they were not declared, or not evident in pictures of the item.

    I wouldn't worry about the tight hood, personally I always leave them in place anyway, except on lenses where I can't close the bag with the hood on.
  4. AndyTake2

    AndyTake2 Well-Known Member

    First glance it looks like damage to e lens coating. It is unlikely to ever pose a problem.
    If your lens hood is tight, go round it wi a pencil. Graphite is a great lubricant, just remember to blow off any excess.

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