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Lens problem or M43 contrast focus problem?

Started Nov 30, 2012 | Discussions
Lawrence W Contributing Member • Posts: 834
Lens problem or M43 contrast focus problem?

I took my new Panasonic G5 with the 100-300mm for a trip recently and came back with mixed feelings on this combo.

In Vegas, I took some shots of 2 girls by the pool across the street, and the zoom lens works perfect, whether optical 300mm, or even with 4X digital zoom. See attached. The 20mm f1.7 shot is just to put it into perspective.

However, when I tried it for birding, it was disappointing. somehow, it just cannot focus properly with a flock of birds on the pool, even stepped down to f10 with shutter speed of 1/500 and O.I.S. on.

What could be the problem? Contrast focus system cannot work when all birds look alike? Bokeh problem?

 Lawrence W's gear list:Lawrence W's gear list
Olympus PEN E-PM2 Olympus E-M1 Sony a6300 Sony a9 II Sony a7 IV +11 more
Panasonic Lumix DMC-G5 Panasonic Lumix G Vario 100-300mm F4-5.6 OIS
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s_grins
s_grins Forum Pro • Posts: 14,011
Re: Lens problem or M43 contrast focus problem?

Maybe it is F=10 and diffraction cause by iris.

Also when you have large water body it is every time like that

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http://g1.img-dpreview.com/20AE148C45244CBE9FB1585EDA32B1C1.jpg

 s_grins's gear list:s_grins's gear list
Panasonic G85 Panasonic Lumix G 20mm F1.7 ASPH Sigma 30mm F2.8 EX DN Sigma 60mm F2.8 DN Art Panasonic Lumix G Vario 14-140mm F3.5-5.6 O.I.S +3 more
minniev Veteran Member • Posts: 4,365
Re: Lens problem or M43 contrast focus problem?

I am hoping some more people will respond to you because I have the same question about the CDAF. I agree with the other poster that diffraction may be a contributor to your problem. BUT - I have struggled with my OMD for 6 months with the impossibility of photographing a white bird with any consistent success. I've tried manual and auto focus, all kinds of lenses, apertures, shutterspeeds, tripods vs handheld, IBIS on/off. Once in a while I'll luck up but mostly I fail. I can easily capture the buzzard or blue heron right next to the white pelican or egret in the same light against the same background, but the white bird will not happen for me. I've got to get out the DSLR to get him. The OMD is a complicated little beast and there may be some trick I am missing, but I'll follow your thread with interest. Incidentally, those dark birds in the middle right in your photo seem more detailed than the flock of whites.

sb123 Senior Member • Posts: 1,162
Re: Lens problem or M43 contrast focus problem?

Where is the camera focusing?  If you are using multipoint, then green squares should light up over the focus points.  To be most sure set the focus to single point small box, and set it exactly where you want.  To start out try this with focus mode set to AFS.  You should get a sharp result in the plane of focus.  Where that plane should be is your choice.

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Steve Barnett

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