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02-19-2016, 07:04 AM   #1
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Focus issue with K-3ii with 18-135mm

Just got a new K-3ii and a slightly used 18-135mm lens. In comparison with my old equipment (primarily GH4 with 12-35mm and 35-100mm lenses) images look very soft. I tested the back focus and ended up putting in a -5 for the lens back focus. Most of my images were early morning using ISO's in the 200 to 1600 range. I'll try later in bright light, but I can't see where that changes much about soft-ish images.

Interested with anyone else with experience with this combination?


02-19-2016, 07:49 AM   #2
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Where does the softness lie (centre, border, corners?), which apertures have you used and which focal length were the pictures taken as? The 18-135 does not exactly have a reputation for being sharp, especially towards 135 mm, and especially at the borders of the image. The centre, however, is supposed to be quite sharp.
02-19-2016, 08:53 AM   #3
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Please post some samples so that we can investigate rather than speculate.

You can also check other users' images with that lens with our photo search feature.
02-19-2016, 09:43 AM   #4

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You may want to make sure you are in AF.C mode, and that you are in "Spot" focus, then try some tests. Just a suggestion. I have a K-3II and have never had negative focus issues.

02-19-2016, 04:32 PM   #5
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I have 2 lenses: the 18-135mm and the 15mm DA. The 15mm is pretty sharp in the middle but gets quite fuzzy on the sides and corners. This may be the curvature of the WA lens, I will run some more tests. The 18-135mm is fuzzy all over and gets really bad in the corners. But I want to check it all over again before I put anything on here.

So, I decided to re-do the focus test, and reset the focus adjustment to zero. The 15mm was hard to test because of DOF, but seemed to be right on. However, the 18-135 was off quite a bit.... see the attached heavily cropped sample. This was at 115mm, f5.6, 1/15 on a tripod, AF.S, spot mode, and ISO 280. I'll dial in some compensation and redo the tests tomorrow to check it all over again.

For my test shots, I go out early so I can use the maximum aperture. I try to get proper exposure at acceptable shutter speed, so it gives me lots of chance to get familiar with the camera. So tomorrow, weather permitting I will redo the test shots and post them here. Thanks for your help.
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Last edited by Johnontheroad; 02-19-2016 at 04:39 PM.

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