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04-22-2008, 04:56 AM   #1
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Something very strange happened today.

I have just aquired the highly praised Sigma 70mm DG macro. Im using it on the K10 and everthing has been going swimingly untill i changed focus points today.

I can aquire sharp focus with all points except the 2 outermost points where i get an FF problem. I tried with other lenses and all points function as expected so it cannot be the K10.I have never come accross an issue like this before.

Should i send the Sigma back or live with the focus points that do function with this lens? What do you think, any experiences?


04-22-2008, 06:26 AM   #2
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NeverSatisfied's Avatar

Join Date: Dec 2007
Location: S.E. Michigan
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Seems to work on mine

Funny you just brought this up, now that Spring is here my Sigma 70 has just come out of "hibernation", and I've been using it a lot these last two days. And I have been changing focus points extensively, with no problem. (Only wish the K10D had a few more selectable focus points! But that's nitpicking, I've really enjoyed this camera.) I am amazed by the sharpness and clarity of this lens. Since you just got it, if I were you I'd sent it to Sigma or else return it to the retailer for an exchange. (Unless some other users have some additional insight on this problem.)
04-22-2008, 06:40 AM   #3
Lowell Goudge's Avatar

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just a dumb thought but try rotating the camera 90 degrees and take the shot using the outer focusing points.

I think I read somewhere that only the central point is a cross focusing sensor, and maybe the outer two points are having difficulty with the subject at the particular angle you are shooting at.
04-22-2008, 07:25 AM   #4
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Original Poster
Hi Lowell

I tried it and it didnt seem to change anything. However i did notice that the red marks for the outermost focus points are much larger than the rest, why is that?

Anyway, i just re-tested with my kit lenses and this is only happening with the Sigma.

04-22-2008, 07:27 AM   #5
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Hi Never

You are right, the lense is helish sharp, the problem only occurs with the 2 outermost points and its got me stumped.

04-22-2008, 11:09 AM   #6
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Sorry to bump this

But im wondering if i have missed something with the outermost spots? Is it me am i getting something wrong? I just need to go through the possibilities before i return it to the dealer tomorrow morning.


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