dust in lens

[Portrayed1]

i am looking at some lenses on ebay and some of them say that there is dust specks internally but that it doesnt affect the quality of the image

i think that it would...am i wrong or right?
thanks!

 

[Big Mike]

There is always a chance that it will affect the images...but for the most part, anything on or in the lens is so close to the focal point of the lens...that it's going to be so out of focus that it won't show up in any images.

 

[ksmattfish]

Within reason dust specks in the lens do not affect image quality. Almost every lens will have dust in it if you look hard enough; even brand new ones. If the lens is full of lint and sand that's another matter. A lens seller that mentions dust specks is a lens seller that wants to make sure you know about everything; I'd say it's a good sign, as most lenses sold without mention of dust specks will also have them.

I've got several classic, medium and large format lenses with air bubbles in the glass (result of the glass pouring technology of the day). The bubbles are many times larger than dust specks, and they do not effect the photo in any noticeable way.

 

[Dao]

ksmattfish, remember this post?

http://www.thephotoforum.com/forum/...oto-gallery/144728-dust-scratches-lenses.html

 

[Garbz]

Dust on the sensor would block light, Dust on the lens would scatter light, but given the size of the lens element and the scattering effect you would need a pretty huge gob of dust and a very tiny aperture to resolve it.

Ignore it. The 18-200 I borrowed for my trip is absolutely filthy inside and it hasn't affected the quality.