bad lens? flash phenomenon? auto focus setting?

bad lens? flash phenomenon? auto focus setting? · 08:38 PM

Hey guys/gals

I've done a lot of holiday snapping these past couple of days and I'm noticing something with my lens that is puzzling me. Given that I picked this Sigma 28-105 for next to nothing, I'm not going to be sad if it's the glass, but just out of curiosity, can you look this over and give me some input?

As you can see the children in front and my wife on the right are in focus and sharp. I, however, am not. This is not only in this photo, but many/most others as well where the left side blurs out slightly. No, I didn't move.

So, I ask...bad lens or something to do with flash or should I revisit my auto focus setting? For particulars, here are the key EXIF data: 28mm, ISO 200, F5.6, SS 1/45, aperature priority, pattern metering, flash on. For PP, all I did was resize and auto contrast. No sharpening this time.

Have a look please, LMK what you think...

Peter Zack · 12-25-2007, 09:23 PM

Assuming it's not simply and issue of shallow DOF and your other lenses work fine. I'd guess that your lens has a delaminated element. Its got a loose or out of alignment element inside. Might have been bumped/dropped at some point in it's life.

SouthShoreRob · 12-26-2007, 07:13 AM

Originally posted by Peter Zack

Assuming it's not simply and issue of shallow DOF and your other lenses work fine. I'd guess that your lens has a delaminated element. Its got a loose or out of alignment element inside. Might have been bumped/dropped at some point in it's life.

Seems very plausible. Thanks.

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12-25-2007, 09:23 PM	#2
Peter Zack Pentaxian Moderator Emeritus Join Date: May 2007 Location: Edmonton Alberta, Canada Photos: Gallery \| Albums Posts: 10,643	Assuming it's not simply and issue of shallow DOF and your other lenses work fine. I'd guess that your lens has a delaminated element. Its got a loose or out of alignment element inside. Might have been bumped/dropped at some point in it's life.

12-26-2007, 07:13 AM	#3
SouthShoreRob Guest	Originally posted by Peter Zack Assuming it's not simply and issue of shallow DOF and your other lenses work fine. I'd guess that your lens has a delaminated element. Its got a loose or out of alignment element inside. Might have been bumped/dropped at some point in it's life. Seems very plausible. Thanks.