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



## Canon Rumors Guy (Apr 11, 2019)

> 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...



Continue reading...


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## Gillettecavalcad3 (Apr 11, 2019)

Meanwhile, ...Sony releases new firmware...


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## Canon Rumors Guy (Apr 11, 2019)

Gillettecavalcad3 said:


> Meanwhile, ...Sony releases new firmware...



Can I install it on my EOS R?


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## neuroanatomist (Apr 11, 2019)

Canon Rumors Guy said:


> 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. 

(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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## PureClassA (Apr 11, 2019)

Then we all wonder how the hell it got in there in the first place


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## neuroanatomist (Apr 11, 2019)

PureClassA said:


> Then we all wonder how the hell it got in there in the first place


RTFM.



> Tight seal structure ensures excellent dust-proof and drip-proof performance.



It says nothing about being sealed against flies.


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## Mt Spokane Photography (Apr 11, 2019)

Fly eggs are very tiny and can get in. I hope it wasn't laying 10,000 more!


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## Dantana (Apr 11, 2019)

Seems like an expensive way to catch a fly.

What I really want is an internally focusing, large aperture, stabilized fly catcher for under $1000.


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## QuisUtDeus (Apr 11, 2019)

Gillettecavalcad3 said:


> Meanwhile, ...Sony releases new firmware...



So you're saying you already knew about that from elsewhere and didn't need to read about it on a Canon-focused (SWIDT) site, and instead got alerted to a very interesting blog post? I assume you're meaning to thank CRG.


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## degos (Apr 12, 2019)

> 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 (Apr 12, 2019)

degos said:


> 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 (Apr 12, 2019)

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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## blackcoffee17 (Apr 12, 2019)

Mt Spokane Photography said:


> Fly eggs are very tiny and can get in. I hope it wasn't laying 10,000 more!



A fly larvae needs food to develop, don't think there enough of that inside of a lens


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## blackcoffee17 (Apr 12, 2019)

The back of the lens is not sealed when taken off camera so its easy for anything to get in


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## mikebg (Apr 12, 2019)

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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## tvb (Apr 12, 2019)

Objects located close to the lens surfaces usually are visible very clearly in bokeh circles :3 Sadly they didn't test it this way...


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## Pape (Apr 13, 2019)

so always when you put rear cap to lens ,remeber check insects inside cap


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## stevelee (Apr 13, 2019)

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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## Deleted member 91053 (Apr 13, 2019)

Had a tiny spider in the viewfinder when I had my 1D4 - ruined loads of images! It was just too much fun watching the antics of this tiny fella so I missed lots of birdies

I often wonder what happened to him/her - was it the Sensor Cleaning Monster


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## Don Haines (Apr 13, 2019)

blackcoffee17 said:


> A fly larvae needs food to develop, don't think there enough of that inside of a lens


Perhaps the fly found a flourite element


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## scyrene (Apr 14, 2019)

Funnily enough a few months ago, I discovered a small moth inside my 24-105L lens. How and why it got in there I don't know, but its body was loose inside and clearly visible. The lens was old and I wasn't going to sell it, so I decided to open it up to remove the moth and clean it. But first I took some shots to see what effect it had, and I couldn't detect much, and decided that I was likely to make the lens worse by fiddling with it, so I didn't bother. I've been using it ever since and can't say the images are any worse than before.


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## londonxt (Apr 14, 2019)

I remember a small fly got inside my 5D mirror chamber and walked across the focussing screen as I was framing a photo over a city view, very B-movie-esque but nearly had a heart attack.


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## Hector1970 (Apr 14, 2019)

I changed my lens one time on my 5D III and placed the camera face down on a piece of furniture. When I got the new lens on when I looked through the viewfinder I could see a little insect walking around. It appeared for a few days and I couldn't get rid of it. Eventually it died and it remained in the view finder for a while until I managed to shake it out.


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## SkynetTX (Apr 15, 2019)

So the IS in the name of the lenses should now mean "Insect sealed."


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## Kit Lens Jockey (Apr 23, 2019)

johnf3f said:


> Had a tiny spider in the viewfinder when I had my 1D4 - ruined loads of images! It was just too much fun watching the antics of this tiny fella so I missed lots of birdies
> 
> I often wonder what happened to him/her - was it the Sensor Cleaning Monster


Um yeah if using my camera required me to have a tiny spider that close to my eye every time I looked through the viewfinder that camera would be sold very quickly.


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## Deleted member 91053 (Apr 23, 2019)

Kit Lens Jockey said:


> Um yeah if using my camera required me to have a tiny spider that close to my eye every time I looked through the viewfinder that camera would be sold very quickly.



Why? That tiny spider gave so much entertainment when waiting for subjects to show! We all know how boring wildlife photography can be at times.

Agoraphobic? It was a VERY small spidey............


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## ignomini (Apr 24, 2019)

degos said:


> 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.


No, they are not automatically lying. I have an old Kodak lens on a medium format camera. The lens has bubbles in it. I defy anyone to find evidence in the photos it has taken. You can even use a microscope. Short FL lenses are a different story, but this post is about a longer lens..


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## stevelee (Apr 24, 2019)

johnf3f said:


> Agoraphobic? It was a VERY small spidey............



"arachnophobic" perhaps

(And taking the Latin and Greek literally, someone with agoraphobia would come to a forum with fear and trembling, so probably not posting here.)


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