Focus Oscillation in K3 iii?

Started 4 months ago | Discussions thread
OP JoeOptics314 Regular Member • Posts: 135
Re: Focus Oscillation in K3 iii?

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.

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Please ignore my confusing sentence above in bold face.  What I was trying to say is that I expect the 70-210 mm to be better than the 55-300 mm.  But this is a side issue.  My question is about focus oscillation or drift causing focus to be incorrect sometimes.  Not horrible, but significant enough to degrade a good lens to look worse than a lens with worse image quality.

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David Lees

 JoeOptics314's gear list:JoeOptics314's gear list
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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