Camera Labs

Hi folks, I've got my eye on a used Sigma 135-400mm (canon fit)lens on ebay. It seems cheap, it's currently at £100. The listing states that it has one small speck of metal or dust on the inside of the front glass, but that it has no effect on the images. Is the seller right in saying it will not affect the images notably? And also, is this a good lens at a good price?

Any help and advice would be greatly appreciated, this is a rather large investment for a teenager!

Picture showing the dust/metal (circled)

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Canon 50d, 50mm f/1.8, Sigma 135-400mm APO, Sigma 10-20mm, Lowepro backpack, Velbon tripod, Manfrotto 679 monopod, Hoya filters

www.flickr.com/amr276
Comment and help me learn!

Specks like that generally wont be significant.

If it's auction, you never know what it will end up until the last second as there will almost certainly be snipers.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

You might see it at 135mm F/22, but that's very unlikely.
With longer lenses, you can practically stick your camera into a fence, and the gridlines won't show up, so I doubt that little speck will show up in your shots

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I take pictures so quickly, my highschool was "Continuous High".