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03-15-2012, 03:52 AM   #1
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Extension Tubes on K20D


When I use an extension tube on my K20 with my Vivitar 105 and the camera asks me the focal length, do I leave the setting at 100mm which is the closest that I can get to 105mm or should I add in the actual length of the tube?


03-15-2012, 04:15 AM   #2
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It is to approximate the most optimal setting for the Shake Reduction so you should give the total focal length (lens + tube).
03-15-2012, 04:31 AM   #3
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Noting that SR is probably less effective at close focus, as per the manual.
03-15-2012, 07:47 AM   #4
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As baro-nite said, SR is ineffective for handheld close work with the K20D. How close is too close? I'm not sure, and I'm too lazy to run tests now, but I'll guess that the limit is somewhere around 3-5x the focal length. So roughly, when magnification is around 1:4 or greater, don't expect much help from SR. At such short distances you'd best rely on flash or fast shutter or tripod. (Set SR off when using a tripod, of course.)

03-15-2012, 02:43 PM   #5
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Original Poster
Extension Tubes on K20D

Hi All,

Thanks very much for your informative replies.


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