How does a dead fly in a Canon EF 70-200mm f/2.8L IS II affect image quality?

Canon Rumors Guy

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  • Jul 20, 2010
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    I bet the question of how a dead fly inside a Canon EF 70-200mm f/2.8L IS II affects image quality wasn’t something most of us would have ever seen tested, but alas, the folks at Lensrentals.com decided it was time to answer the query.
    From Lensrentals.com:
    So, this seems like a good time to do a blog post showing that 1) this big-ass fly had almost no effect on image quality, so that little dust speck you’re frantic about sure doesn’t, and 2) getting flies (or dust) out of a lens is a lengthy and difficult process that takes a long time.
    Now I think we all agree that the fly really did need to be removed, but by the time you finish this post, hopefully, you’re going to agree with me that that dust speck in your lens probably is just fine right where it is. Not to mention, I bet there’s a really good chance that if we remove this fly, the...

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    neuroanatomist

    I post too Much on Here!!
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    Jul 21, 2010
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    2) getting flies (or dust) out of a lens is a lengthy and difficult process that takes a long time.
    Not really...just send in a spider to catch the fly. :p

    (Cue ensuing responses about birds, cats, dogs, but after that the goat can just eat the lens and the fly will no longer be a problem.)
     
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    degos

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    Mar 20, 2015
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    so that little dust speck you’re frantic about sure doesn’t

    Of course it does, just not measurably so. But by the time we're using half-gigapixel sensors then we'll have to reassess.

    I do hate the 'generalisation' of language. When I see a lens listing that says 'mark on objective has no effect on image', I know they're lying and I move to the next listing. Everything in a lens has an effect on image quality. Just because we can't see it right now doesn't make it acceptable to lie.
     
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    Metalex

    I'm New Here
    Feb 6, 2019
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    Of course it does, just not measurably so. But by the time we're using half-gigapixel sensors then we'll have to reassess.

    I do hate the 'generalisation' of language. When I see a lens listing that says 'mark on objective has no effect on image', I know they're lying and I move to the next listing. Everything in a lens has an effect on image quality. Just because we can't see it right now doesn't make it acceptable to lie.
    You think they're lying? Really?! That's a real stretch.

    A "half-gigapixel" sensor would not render that dust-speck any more in focus and visible than today's sensors.
     
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    Ian_of_glos

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    Jun 12, 2012
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    Surely it depends on which lens you are using.
    When I am taking pictures at rugby matches I frequently find that there are small splashes of mud on the front element of my 400mm lens but they never show up in any of the pictures. However, I once managed to leave a thumb print on the front element of my 8-15mm fish eye and you could see it clearly in all the pictures.
     
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    mikebg

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    Jun 14, 2013
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    I upgraded my old 70-200 f/4L a while ago to the new II version. I had hoped to sell the old one in part exchange, but when the shop checked out the lens they noticed a piece of broken glass stuck somewhere between the rear lens elements. They showed it to me so I could see for myself. No question what it was, but how did it get there? Probably quite early on after buying the lens, I think. It dropped and got a nasty bash. I guess that the edge of one of the lens elements broke and got lodged there.

    Did I notice it at all over maybe 10 years or more? No.
     
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    stevelee

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    Jul 6, 2017
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    Supposed history of the waiter joke:

    IN HER anthology, One Hundred Renaissance Jokes, Barbara Bowen identifies a Latin epigram by Sir Thomas More as a likely forerunner. At a banquet, a guest removes some flies from the loving-cup, drinks, then replaces them, before passing it on with the remark: 'I don't like flies myself, but perhaps some of you chaps do'.
     
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