Speck of dirt in Canon 70-200 2.8 IS USM Lens.

Hi there...


I just purchased the Canon 70-200 2.8L IS USM and thrilled about the picture quality and the bokeh this lens is providing me. I did however notice, as usual, once I got home, a very tiny speck of dust (a particle of some sort) that looks to reside just under the front glass. It is really tiny and barely noticeableand about .75 inches from the side.


I had a friend look at it and could not really notice this particle until is was pointed out to him.....


At the sound of being anal, *SHOULD* I return this lens to the retailer and take a chance of recieving a copy that is not as sharp or just deal with it and continue having fun, mind you this lens is not easy to get, *slim pickings*.


I do not notice this particle anywhere in the photos, most likely due to the fact it's so tiny!


I'm a little irked at the fact that I just emptied my wallet on this lens.


Your opinions are welcomed.


Thanks

Keep it and go take lots of pictures with it. Unless it shows in the pictures then nothing to worry about IMHO.

Don't worry about it. I've got dust on my sensor, dust in my lenses, and dust on my filters--and my pictures still come out pretty damn good. Something that small and insignificant won't affect picture quality.

I feel the same way elmo_2006, i'm very anal with all my toys, but i also think you are looking at the situation the correct way. You should not risk getting a replacement if this one is delivering great quality, specially if you can't notice the spec on your pictures.


After shooting with it for a while you will forget all about it.

Long as it doesn't affect your photos dont' worry about it.


If it's possibly fungi, then you might have a problem... if it's brand new, I'd just return it if you're that concerned, most stores should return it within a week/month, especially under warranty.



Explain why you're returning it... I think they'd understand when you're buying a VERY expensive lens.

Sounds like you got yourself some genuine Canon dust. I would be extremely surprised if it affects anything. Some day you will probably need or want to send your lens in for calibration or adjustment or a general cleaning. Have them remove it then.

Call me anal, but I think you should have it cleaned. Come on, you spendalmost 2 grand on a lens and it comes with dust.

I have decided to continue working with this lens.


I appreciate the comments and thank you.

Here's something I discovered.


Take any lens, and remove both end caps. If you take a strong flashlight and shine it straight through the lens barrel, you will see dust. It is everywhere. Even the "sealed" lenses have it. These things are not airtight, nor are they designed to be. Even hard drives are not hermetically sealed (though they do have a "breathing hole" that employs a particle filter). The dust is so small that you can't really see it unless you shine a bright light into the lens--which means it won't degrade optical quality, because in the course of taking photos, you never actually shine that bright a light source through the lens.


So in my view, something has to be really huge in order to make a visible impact on image quality; and it is only to the extent that dust particles inside the lens may be indicative of improper manufacturing or a lens defect that I think it should be serviced. If there was a hair in my lens, metal shavings in the barrel, or an air bubble in the glass, I would send it back because those things tell me the QC was inadequate, not because any of those things would make a noticeable impact on the image quality. However, a small speck of dust--even in an L lens--is not significant. Shine a flashlight through that lens and you'll be surprised what else you can see.

Dust in the lens does not affect quality:


http://www.lensrentals.com/news/2008.10.30/front-element-scratches


However, it does affect resale value, because there are some people out there who are unaware that it does not affect quality.

<span style="font-family: Arial; color: black; font-size: 12pt; mso-ascii-font-family: Arial; mso-fareast-font-family: +mj-ea; mso-bidi-font-family: Arial; mso-color-index: 1; mso-font-kerning: 12.0pt; language: en-US;"]Another point about dust or a glass defect, does the defect's light path actual land on or offthe image sensor?


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The lens will focus a circle image onto the back of the camera sensor's area, but only a rectangle area will land on the sensor itself, so the area off the sensor never gets captured in the photo.



<span style="font-family: Arial; color: black; font-size: 12pt; mso-ascii-font-family: Arial; mso-fareast-font-family: +mj-ea; mso-bidi-font-family: Arial; mso-color-index: 1; mso-font-kerning: 12.0pt; language: en-US;"]The resale inspection of the defect may cause an issue, buttaking an actual image with the lens should put the issue to rest.

I've taken multiple images and I cannot for the life of me locate the *particle* in the photo even taking an image of a white sheet of paper - it's simply not there.


The particle in question isso tiny that any Joe off the street cannot locate it unless I point it out to them.

I, like others, have high standards and expectations with "L" glass and as such after dishing out some serious coin, I was, frankly, irked that something like this has occurred, but hey, crap happens. Unless I can see it in the image, I'll continue to happily snap away!


Cheers.