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Author Topic: Canon 70-200 2.8L bad glass?  (Read 6179 times)
robscow1@hotmail.com
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« on: January 21, 2006, 12:07:23 PM »
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I recently bought a 70-200 2.8L canon lens on the recommendation of a friend for its high quality and excellent optics.  The other night, before installing the lens on my camera, I was checking for dust on the glass by looking through the lens alone at a bright light.  With the focal length @70mm, I could see that the interior lens was covered with what look like dust.  This lens is only 3 months old and has been used maybe 10x and always kept in the case.

I took some photos of this problem and I'm hopeful that someone with some experience can let me know if this is common or a problem.

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Sheldon N
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« Reply #1 on: January 21, 2006, 09:21:15 PM »
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I can see a few specks in my 70-200mm f/4 L. Hadn't noticed them before today, and they've never given me any problems. I'd suggest doing two things...

1) Take some pictures with the lens. They should be wonderful. If it's not giving good pictures (assuming proper technique is used), then maybe there's a problem.

2) Swing by the camera shop, see if they have another lens that doesn't look the same way. Maybe you could exchange it for peace of mind.

It probably shouldn't affect image quality. I bought a 35mm f/2 on ebay that went for a song because the owner complained about a piece of dust inside the lens. He posted photos showing how the dust inside the lens appeared in a photo of blue sky. When I got the lens, sure enough, there's a larger dust speck inside it. However, it didn't show up in any of my photos.

The seller simply had dust on his sensor.
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Jack Flesher
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« Reply #2 on: January 21, 2006, 09:41:54 PM »
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What you posted looks bad -- really bad.  

While it is really tough to diagnose via web jpegs, it appears that in addition to the many specs, it also looks fogged.  If it is fogged, I would suspect the specs are not  dust, but vaporized lubricant.  This can happen if the lens is exposed to very high heat like the trunk of a car during a hot summer day.

Best to have it professionally cleaned.
« Last Edit: January 21, 2006, 09:43:03 PM by Jack Flesher » Logged

roli_bark
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« Reply #3 on: January 22, 2006, 12:47:37 AM »
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Oh my....this really looks bad. Maybe fungi.
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Tapeman
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« Reply #4 on: January 24, 2006, 01:39:35 PM »
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Mine looks nothing like that, and it is 7 years old. Exchange it if you can.
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Tapeman.  Canon shooter. Acquiring gear for 25 years.
lester_wareham
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« Reply #5 on: January 30, 2006, 06:27:15 AM »
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Quote
I recently bought a 70-200 2.8L canon lens on the recommendation of a friend for its high quality and excellent optics.  The other night, before installing the lens on my camera, I was checking for dust on the glass by looking through the lens alone at a bright light.  With the focal length @70mm, I could see that the interior lens was covered with what look like dust.  This lens is only 3 months old and has been used maybe 10x and always kept in the case.

I took some photos of this problem and I'm hopeful that someone with some experience can let me know if this is common or a problem.

I have never seen anything that bad before, even in +20 year old lenses, I think it must be fungus. Has the lens been in a damp environment or suffered condensation?
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robscow1@hotmail.com
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« Reply #6 on: January 31, 2006, 12:33:28 AM »
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I have never seen anything that bad before, even in +20 year old lenses, I think it must be fungus. Has the lens been in a damp environment or suffered condensation?
[a href=\"index.php?act=findpost&pid=57091\"][{POST_SNAPBACK}][/a]

No it hasn't.  Its only a few months old.
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robscow1@hotmail.com
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« Reply #7 on: January 31, 2006, 12:43:25 AM »
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I called the Canon service and this is the emailed reponse they sent after discussing the problem and viewing the images on this site.


Thank you for your patience in our review of the images you provided.  I was able to forward the link to our Technical Support Engineers and asked their opinion.  The question that did come up is how is your image quality when you used the lens.  If the image quality is good, there is little need for concern.  There are naturally subtle imperfections in the glass and the Factory Service Center would be the only facility capable of determining if the presence of the "speckles" is with Factory tolerance   Since the last time the lens was there for cleaning and it wasn't addressed, if you should return the lens to our Factory I would be more specific as to your concern.  If it is considered to be a defect in manufacturing, the Factory Service Center would be able to take appropriate action.  I can assure you that very strict quality control is implemented in the manufacture of our lenses and my hope would be that this is normal.  Thank you for choosing Canon and please respond if I can help you further.

Sincerely:


Senior Technical Support Representative
Canon Photographic Products Group
www.usa.canon.com
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Sheldon N
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« Reply #8 on: January 31, 2006, 06:56:22 PM »
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So how do you find the image quality from the lens?
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robscow1@hotmail.com
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« Reply #9 on: February 01, 2006, 11:58:33 PM »
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So how do you find the image quality from the lens?
[a href=\"index.php?act=findpost&pid=57223\"][{POST_SNAPBACK}][/a]

I haven't been able to objectively evaluate its impact on photos yet- though I did have a problem getting sharp photos of low light cityscapes (even when stopped to down to F4 and 5.6).
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robscow1@hotmail.com
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« Reply #10 on: March 07, 2006, 09:11:09 AM »
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I've now sent and received the lens from the Irvine service center for a second time.  This time I directed the customer service agent to this website to see the photos and put with the lens.  He said they would take care of it.  I also told them to contact me before returning the lens so I could verify that they had actually fixed or at least addressed the problem.  Well the lens came back last Saturday and I was never contacted beforehand and it had their standard form letter stating the lens had been cleaned and adjusted.  The problem wasn't addressed or fixed.  New lens buyers should throughly check out their lenses before the 30 day return period expires- even if it is a top of the line lens.  You do not want to deal with Canons customer service nightmare.
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