E-M1 Focus problems

Started Mar 13, 2014 | Discussions thread
OP lnikj Regular Member • Posts: 190
Re: The words that dare not speak their name

jalywol wrote:

lnikj wrote:

Following a "tip off" in a PM that pointed me to various relevant posts I am now starting to wonder if what I am seeing in some of my images is … wait for it … *shutter shock*.

There I said it. I know that I'm not allowed to say this about the E-M1 and will probably now be derided as a troll. I will certainly be attacked for being unscientific and having questionable shooting technique I am sure.

I have been going back through my E-M1 images with a fresh eye. This isn't that easy as I am a pretty ruthless with my images and throw most of them away for a variety of reasons, not least for failing to obtain critical sharpness at 1:1.

What my admittedly unscientific study has shown is that my softest E-M1 images are all to be found at about 1/80s - 1/320s, with a particular bias at 1/200s. I have beautifully sharp images handheld at 1/15s and plenty at 1/640s or above.

I generally shoot images in two ways. In the evening on a tripod with IBIS off and slow shutter speeds, or handheld out when walking with my other half in the middle of the day through to late afternoon/early evening. Unsurprisingly the latter leads to a lot of shots at f/7.1 (my self imposed 'diffraction limit') and at shutter speeds in the vicinity of 1/200s.

I was looking at these images suspecting diffraction of being the culprit but maybe it isn't. Maybe it is the words that dare not speak their name.

I know that doesn't explain the first image I posted (1/500s) so I guess that will add fuel to the fire.

Shutter shock occurred to me when you first posted, but I am honestly not sure if that is what is going on here.

In the first photo, the very topmost pine branches on the trees are in focus, but anything closer is not. In the second, the whitish rocks directly above the green moss appear to be in focus, or at least more in focus than the moss. In the third photo, I am seeing plain, ordinary motion blur/camera shake blur.

I hadn't spotted the topmost branches on the first one. I think you are right.

I don't really see any sharpness or in focus points in the second. I have about 20 shots at this location, shot on the way out and about an hour and a half later, all are in the 1/200s vicinity, and they are focused in different places. Not one is critically sharp.

You may be right about the third one. I have about 25 shots here. All between 1/160s and 1/250s. All exhibit the same problem.

I shot at all 3 locations with my Sigma DP3M. It's not a fair comparison but all shots were either at 1/125s or 1/250s. Of about 30 shots with this camera not one is anything other than crystal clear. The DP3M has no image stabilisation.

I took many other shots that day with the E-M1. Almost everything above 1/320s is sharp, and the few I have below 1/40s are sharp.

The first two photos are a bit of a puzzlement as to why things are soft....It might be a combination of factors, rather than any one. Diffraction, slight offset of focus point, subtle movement during the shot, and perhaps shutter shock, are all potential contributors. I don't know what is doing it in your shots, however.

I find that when I am not paying attention to my holding technique, I am more likely to see things that look like shutter shock on the EM1. I have one shot in between two others of a brick building front that would be a poster child for SS...however the other two on either side of it with the exact same settings were perfectly sharp, and I when I went over them, I remembered that I had gotten sloppy with my holding technique for the bad one....no shutter shock in that particular case, just user error. That may be a factor in this...or not. I do believe that the IBIS seems to be more capable of accommodating user induced camera movement during very slow shutter speeds than it is in the "danger zone"; whether that is what you are seeing or SS or something else, I honestly do not know.

It's all possible and I will pay more attention to this.

I would test your focus point accuracy first, if you are trying to run this down. It's possible that the camera is simply not focusing correctly on the exact spot it is supposed to. I know there is theoretically not supposed to be back or front focus on a CDAF sensor, but I have personally had one camera that did it (my first GH2....I was able to exchange it for another since it was obvious from when I first got it. Its replacement had no problems with focus accuracy at all). If that turns out ok, then I'd do a tripod vs hand held comparison to try and narrow it down further.

I think I'm going to have to.

Oh, and the 1/8 second delay is also a good idea to try. I leave that on all the time on mine; just a habit I got into with my PENs and I have had no complaints on the EM1 sharpness with it on, so I just leave it on. YMMV, of course.....

I hope you can get to the bottom of this.



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