K-7: DA* 16-50 & DA* 50-135 Focus Tests - Comments/Advice?

Started Feb 6, 2010 | Discussions thread
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Rhombuss
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K-7: DA* 16-50 & DA* 50-135 Focus Tests - Comments/Advice?
Feb 6, 2010

Hi all, just picked up a K-7 with the above lenses. Been fiddling around with them to ensure they're properly focus calibrated. Shot on a tripod, ISO was kept at constant 200 with Aperture priority and automatic shutter. Probably could have used more light for proper exposure, but this is strictly a focus test. Aperture was bumped incrementally decreased two steps at a time from F2.8 to F7.1, then a last shot at F8.0. These are all 100% crops, shot in JPEG. What do you think?

DA* 16-50mm - 16mm Focal Length - TEST

Observations:

At F2.8 the lens seems soft. Sharpness improves stopping down to F3.5, then very slight improve as the aperture decreases.

DA* 16-50mm - 50mm Focal Length - TEST

Observations:

Again, soft at F2.8 with slight improve at F3.5. Sharpness drastically improves at F4.5 and continues to F8.0 with incremental improvements.

DA* 50-135mm - 50mm Focal Length - TEST

Observations:

Not quite sure what happened at F2.8, perhaps the AF mis-focussed. I'll try to get around to retesting it at F2.8 at the wide end, hopefully this is not indicative of the lens. Sharpness stopping down to F3.5 and beyond seem sharp.

DA* 50-135mm - 135mm Focal Length - TEST

Observations:

This lens seems to perform great at the telephoto end. Sharpness is pretty spot on from F2.8 to F8.0 with very slight improvement as the aperture decreases. Even at F2.8 the sharpness seems very good.

Being my first dSLR, I'm not sure if these focus samples are in line with expected performance. Comments are very much appreciated. Thanks!

-Phillip

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