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| LX100 Amsterdam Centraal correctly focussed. Good image quality at f1.7 |
On user forums over the last few months there have been some posts referring to situations where the LX100 may experience difficulty achieving correct autofocus.
I have now made several thousand exposures with my LX100.
In the vast majority of cases the camera achieves single AF very quickly with great accuracy and reliability.
I was recently on a photo tour of Iceland with a group of enthusiast photographers, most wielding current model full frame DSLRs and big fat lenses.
Some of the photo chat each day consisted of various grumbles, mostly about the light which was frustratingly overcast but I also heard quite a few complaints of pictures out of focus.
As in…..Darn….didn’t quite nail focus on that one…..
I gave up using DSLRs years ago mainly because of their unreliable single shot AF.
Compared to the DSLRs in Iceland the LX100 was a shining little light of AF reliability.
LX100 Continuous AF in Burst Mode is also very competent, enabling coverage of close up sports such as junior/amateur basketball and the like, indoors or outdoors
However there is one particular type of subject which can trip up the LX100s AF system.
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| From the same camera position as the top photo, OOC JPG. The image is not in focus. The AF box was central, default size. The problem is the bright light coming through the window just to the right of and below the center. The camera was racking focus back and forth, indicating a problem. I moved the focus box to the left of center with no further problems. |
The issue is not so much the subject itself but the character of the light coming from the subject to the camera.
The photos illustrate this.
The camera’s AF system gets confused when confronted by multiple small bright light sources or sometimes, as with Amsterdam Centraal, a few large bright light sources.
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| Waterfall in Iceland with a little ladder for the fish. (on the left) Really, that's what it's for. AF box was in the center. The camera indicated "In Focus" but as you can see it is not. The sun shone for a few minutes producing bright sparkly reflections on the water. I think that is what has confused the AF system. |
Not shown in this set of photos, I have also seen the problem in a shopping center dressed up with multiple bright Christmas lights.
I have tried to deal with this using manual focus but not had much luck. In fact I find AF more reliable than MF on the LX100. I find the manual “in focus” point difficult to see without peaking and no better with peaking.
Indeed in some of my tests I found the peaking function difficult to use as it is not “peaky” enough and will appear to indicate some subject element in focus when that is not the case.
I have no trouble with MF and peaking on the FZ1000 in the same situations.
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| Sydney this time. AF box central. Sparkly backlighting coming through the leaves has produced an out of focus result with no warning from the camera. |
Summary There is a predictable situation in which the LX100 is likely to autofocus incorrectly. The solution is
a) to be aware of the subject/lighting type which can be troublesome
b) to move the AF box to a visually calmer part of the scene.
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