Focus Oscillation in K3 iii?

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JoeOptics314 Regular Member • Posts: 133
Focus Oscillation in K3 iii?
1

I just received a Pentax 70-210 mm zoom and am comparing it against two other lenses that cover that zoom range (150-450mm and 55-300mm PLM).  My initial shots comparing against the 55-300 mm showed it better in terms of blur, which would be quite surprising.  But when I started taking pairs of shots a few seconds apart and compared the pairs taken with identical manual settings I see what appears sharpness differences.

Here are some samples, displayed in ON1 Photoraw.  These are unprocessed raws taken 2 to 5 seconds apart with identical, F/number, shutter speed, ISO.

I am wondering if there is some parameter in the K3 iii menus that might be causing this issue?  I am shooting hand held, but with motion compensation on at what I think are reasonable shutter speeds (1/125 to 1/800 sec).

AF Mode = S

AF Active Area = S

AF Area Restriction = On

Release Priority  (Hmmm.  Should I be using Focus Priority?)

The fact that I see this focus change problem with 2 different lenses, must me the issue is the camera?  Have others seen this problem?  I am hoping there is a different setting that fixes the issue.

70-210mm at 210mm  F/5

150-450 at 200mm F/6.3

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David Lees

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Pentax K-70 Pentax K-3 Mark III Pentax smc DA* 300mm F4.0 ED (IF) SDM Pentax smc D-FA 100mm F2.8 Macro WR Tamron AF 18-200mm F/3.5-6.3 XR Di II LD Aspherical (IF) Macro +7 more
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