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09-13-2011, 09:57 PM   #1

sigma 17-170 hsm macro on k-r - "a" setting?

I am planning on getting a k-r body (1st dslr) at my local photo shop's next sale and am looking for a good all-around lens for it. I am thinking of the Sigma 17-70mm F2.8-4 DC Macro OS HSM for its sharpness, versatility, and speed. It seems like one of the metering modes on the k-r only works with lenses that have the "a" setting on the aperature ring. This lens has no aperature ring but is a modern lens specifically designed for digital cameras. I am not familiar with what the "a" setting is because I have not much prior knowledge of pentax lenses.

Does anybody know if this lens (and/or modern sigma and tamron lenses designed for digital cameras) has the "a" setting or will work with cameras that need it?


09-13-2011, 11:10 PM   #2
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The A setting only applies to lenses with aperture rings (it is a physical stop on the ring that enables auto-aperture mode). Modern lenses lack the aperture ring and instead are in "A" mode by default. Software in the camera then lets you set the aperture manually.

In other words- this lens will work perfectly on your K-r. So will all the other current sigma lenses:
Sigma Lenses - Pentax Lens Review Database

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