# Why are some portion of my landscape shots totally out of focus?

When shooting landscapes, a single image (say 1 of 200) is totally out-of-focus.

A typical setup might be:

focal distance = 7.1 (x 3.9)
f-number: 5
exposure time: 1/800


According to extended EXIF info, hyperfocal distance was 1.32 m.
There was no high single straw, no low hanging branch, no finger in front of the lens etc.

It was focused to infinity and yet, the result was like this (it's a crop):

I suspect an unnoticed small flying bug might appear in front of the lens while auto-focusing...?

How do I prevent these spoiled images?

Notes:
The camera in question is FujiFilm X-30. (Firmware has been upgraded to 1.01 which fixed another auto-focusing issue.)

Focus mode: S (front dial)
Macro: Off
Focus area: unchanged (in the centre)
Release/Focus priority: AF-S: Release; AF-C: Release
Instant AF Setting: AF-S
AF Mode: Area
Pre-AF: OFF
AF Illuminator: Off


Should I change some of those advanced settings to prevent this problem? My only basic requirement is to keep the ability to point on something, then press the trigger halfway, compose the image (move the subject out of the centre) and take a photograph.

EDIT (> 1 month later)
I've been playing with my camera settings such as turning OIS completely off etc. but no help. The problem is appearing usually when shooting panoramas (not in a camera built-in panorama mode, but in the A semi-auto mode - to be stitched in Hugin). It's especially annoying when one of 10 or 20 images is spoiled, thus the intended panorama is spoiled too.

The only remedy seems to be shooting with the manual focus. However I want to use this camera in a point-and-shoot mode. When I go primarily photographing, I take a bigger camera with me and cay play with a manual mode, focusing and other settings. This camera is used when stopping at the roadside for a few seconds to take a few pictures or a panorama so I expect a reliably working auto-focus mode.

• For a landscape, I'd not use continuous autofocus, but rather focus on the initial shutter release press. From the EXIF data, "Release/Focus priority: AF-S: Release; AF-C: Release", I'm not sure if AF-C (i.e. continuous) is active. – DrMoishe Pippik Jun 8 '15 at 23:10
• I don't even use autofocus for landscape shots. Manual focus usually produces better results if you use sufficient magnification to check for correct focus. – Count Iblis Jun 9 '15 at 13:16
• @user681768917: please show us a complete, high-res, blurred picture with the complete EXIF of that file. – TFuto Jun 9 '15 at 15:47
• @user681768917: also, was your camera focus-hunting before taking the blurred picture? – TFuto Jun 9 '15 at 15:54
• @TFuto: Here you have a correctly focused DSCF3044 and blurred DSCF3045 image with the same settings and EXIF info. Click "Show original" or something similar above too see them in the original resolution. – user681768917 Jun 9 '15 at 16:09