Anyone else with DP2M Front Focus?

Started Oct 10, 2012 | Questions thread
pixtorial
Regular MemberPosts: 114
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Re: Anyone else with DP2M Front Focus?
In reply to approach, Oct 10, 2012

approach wrote:

I tested my new DP2M with a LensAlign at 4 feet. I'm seeing 2 inches of front focus.

Is this par for the course?

Yes, my testing setup was good: tripod, exposure delay, 2000W of halogens.

Sigma tech support (i.e. Marc) says to send it in. It's a brand new camera, and I'm not super-keen on (a) being without it, or (b) subjecting it to a repair-or-repairs.

Thank you.

BTW, the image quality is stellar.

The DP1M/DP2M use contrast detection focusing, not the phase detection focusing of a DSLR. If you are seeing any type of gross focus error and your sure of your test, then it suggests a significant manufacturing flaw in the lens system that should encourage you to return the camera for exchange or repair.

That said, I'm not sure how a contrast detection AF system can misfocus in that manner if you are focusing on the point in space that you believe to be. If it were unable to create a condition of accurate focus at the focus point it would simply continue to try to gain focus, and you would never get focus lock.

I don't mean to question your technique, but would encourage you to review your test procedure from a purely scientific/technical perspective. Do you have the correct focus point selected? Are you certain you understand where within the focus boundary the camera will lock focus? Are you obtaining focus confirmation from the camera? Are you within the hyperfocal range of the lens for the distance and aperture you are shooting the test at?

If this were a DSLR, especially an SD14, I would say well, par for the course. But the SD15 and SD1 have seemed to be, judging by the forums, much more "dialed in" in their focus behavior. And the DPx and DPxM series are all contrast detection AF systems which should not suffer from focus misalignment as you're describing.

Curious to your findings and ultimate outcome, as I'm sure many here are.

Regards,

Bill Collinson

Austin, TX

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