Hello gip,

stacking does not work in this special case.

I would not increase sharpness of shutter. I was questioning if you could improve the sharpness of the distant plane by stacking images focused in this area or if the diffraction effect would neutralize the stacking effect.

Thanks gip for looking and comment. There are only 2 objects in different fields of sharpness. The first one is the shutter - the second one is all of the rest which is in one sharpness line - in the maximum distance. The impression of different sharpness in the small pictures is an effect of the diffraction of the shutter together with the opening of the aperture. The same picture with another aperture shows nearly no shutter and the rest is a sharp picture of the landscape. Regarding the shutter I don´t want to have more sharpness on this.

Your technique is improving. You should try shooting a second image focused on the distant objects then stacking the two images.