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gammamonk

macrumors 6502a
Original poster
Jun 4, 2004
667
108
Madison, WI
I was using my Canon 30D for the first time in a while, and I noticed a fairly large fiber sitting smack dab in the middle of the inner lens of my 28-135mm lens.

Does anyone know how this could have happened, or what I can do about it? I tried tapping the lens gently, but it didn't have any effect.
 

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wmmk

macrumors 68020
Mar 28, 2006
2,414
0
The Library.
I was using my Canon 30D for the first time in a while, and I noticed a fairly large fiber sitting smack dab in the middle of the inner lens of my 28-135mm lens.

Does anyone know how this could have happened, or what I can do about it? I tried tapping the lens gently, but it didn't have any effect.

hard to see from the picture, but it may actually be at the back of your lens. I got dust there on my tamron once, but it was easy to clean off.
 

pdpfilms

macrumors 68020
Jun 29, 2004
2,382
1
Vermontana
As the elements expand and contract with zooming and/or focusing, air moves in and out of the lens. Musta sucked that bugger up.
 

pdpfilms

macrumors 68020
Jun 29, 2004
2,382
1
Vermontana
Oh man, that sucks. Is there anything I can do about it?
Not that I'm aware of, other than bring it to a Canon repair place and have them take it apart. I've got a few dust bunnies on the inside of my lens, but none of them are that big or smack dab in the center. You just got unlucky.
 

ChrisA

macrumors G5
Jan 5, 2006
12,828
2,033
Redondo Beach, California
I was using my Canon 30D for the first time in a while, and I noticed a fairly large fiber sitting smack dab in the middle of the inner lens of my 28-135mm lens.

Does anyone know how this could have happened, or what I can do about it? I tried tapping the lens gently, but it didn't have any effect.

Many lenses change their length when you focus or sometime when you zoom. When they change length air is forced in or out of the lens. Some of the better lenses have seals to prevent dust and water from getting in but most don't

Don't worry about it. A small spec of dust does not block much light. Think of the square area of the speck compared to the square area of the glass. No noticeable effect.
 

G4scott

macrumors 68020
Jan 9, 2002
2,225
5
USA_WA
On a somewhat related note... My Canon G7 has dust inside of the outermost lens element... Unfortunately, I'll have to send it in to have them clean it out, but I don't think it's good at all that dust should so easily be able to get into a built in lens. One or two specks may not be noticeable, but if it keeps building up...

Grr...
 

failsafe1

macrumors 6502a
Jul 21, 2003
621
1
If the dust is near the front elements of the lens it is actually out of focus and will not be seen in the photo. As it gets nearer the rear of the lens it gets sharper and could cause trouble but very doubtful. Dust on sensors for digital are the real culprit not on the lens.
 

bluewire

macrumors member
Aug 28, 2006
99
0
Bay Area, California
God that sucks. My buddy had a huge piece of dust on his viewfinder mirror, how it got there I have no idea but it was very irritating to see this huge dust particle...I felt sorry for him he tried everything to get that thing off but to no avail...
 

job

macrumors 68040
Jan 25, 2002
3,794
3
in transit
Many lenses change their length when you focus or sometime when you zoom. When they change length air is forced in or out of the lens. Some of the better lenses have seals to prevent dust and water from getting in but most don't

Do Canon's L Series lenses have this problem?
 

pdpfilms

macrumors 68020
Jun 29, 2004
2,382
1
Vermontana
Do Canon's L Series lenses have this problem?

Well the thing is, for any lens, no matter how expensive- if there are elements moving around inside, air has to be exchanged. An air-tight seal would create a vacuum and would not allow for movement. Higher-end lenses have moisture-resistant seals, but none are air-tight.

Dust inside the lens is an issue with every lens I've ever used. I don't think there's any way around it.
 

job

macrumors 68040
Jan 25, 2002
3,794
3
in transit
Well the thing is, for any lens, no matter how expensive- if there are elements moving around inside, air has to be exchanged. An air-tight seal would create a vacuum and would not allow for movement. Higher-end lenses have moisture-resistant seals, but none are air-tight.

Gotcha. Thanks for the answer.

I figured since the front of the Canon L lenses don't actually travel, they would be less prone to be affected by dust problems.
 
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