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PostPosted: Wed Aug 12, 2009 3:49 pm 
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Location: Amsterdam, The Netherlands
Hi All,

I hope you are all doing alright..

just a quick question for owners of the said Sigma lens.
I just got a 2nd hand Sigma 28-70 f2.8 lens, and what i notice is that it cannot focus properly if it is zoomed at 70mm. I have checked the front focus ring, and it turns only up to the 5m/12ft mark and does not go all the way to infinity.
is this a normal? focusing below infinity works ok.
is this a defective lens?
thanks in advance.


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PostPosted: Thu Aug 13, 2009 7:49 am 
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The only way to test is to take a photo of something at infinity and see if it's in focus. If it isn't, you've got a defective lens. I had a Sigma 28-70mm for the Sony mount before and that lens gave me no small amount of grief. Sent it to Sigma and they said it was "within specifications".

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PostPosted: Thu Aug 13, 2009 8:04 am 
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Thanks Phil, the issue I have is that the focus ring does not even go to inifinity.. :(
Will have to find a sigma center for repairs, I guess.


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PostPosted: Thu Aug 13, 2009 11:35 am 
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sonnyboy wrote:
Thanks Phil, the issue I have is that the focus ring does not even go to inifinity.. :(


That doesn't matter as long as it focuses correctly. Many lenses allow you to focus "beyond" infinity in order to cope with manufacturing inconsistencies and also focus inconsistencies in the lens at different temperatures. For instance, my Sigma 30mm f1.4 gets tack sharp focus on an object at infinity even though the focus ring is just before infinity. Manually focusing the lens at infinity results in a more blurred image.

This is why you need to see if the lens actually focuses correctly, and not just judge focus by looking at the marks on the focus ring.

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PostPosted: Thu Aug 13, 2009 12:01 pm 
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Location: Amsterdam, The Netherlands
unfortunately, it does not focus at all since it stops before it reaches infinity, if the subject is far away, I cannot get a fix focus at all.
i never had an issue like this in my other lenses...
thanks again.


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PostPosted: Fri Aug 14, 2009 7:09 pm 
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Joined: Thu Jan 17, 2008 5:48 pm
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Location: Denmark
sounds like either defective gears, or like something's ludget in the heliocoide or something , i think you should seek help at a sigma repair center!
even though it's not fun.
good luck
Morten

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Regards, Morten
Sony A200
Minolta 100-300 APO, Minolta 70-210 f4
Minolta 50mm F1.4, Minolta 24mm f2.8
Minolta 28-135, Sigma 90mm f2.8 Macro


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PostPosted: Fri Aug 14, 2009 10:01 pm 
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This definitely should be sent to Sigma for repairs.

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PostPosted: Sat Aug 15, 2009 11:05 pm 
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Thanks Guys...
i brought it for repairs to a sigma certified repair center..they said it should be an easy fix and it should be ready on Monday.


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