A problem with blurry results around foreground objects

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LS_Vee_61
Posts: 2
Joined: 29.01.2018 22:01

A problem with blurry results around foreground objects

Post by LS_Vee_61 » 02.01.2020 02:06

Hello,

I am not sure quite how to describe what I am seeing but there seems to be some calculation error going on where the program doesn't know what to do it is rendering objects behind the foreground object as a kind of halation blur. I have tried both Method B and Method C. Is this correctable in my rendering settings?
CROPPED DETAIL (B,Radius8,Smoothing4) copy.jpg
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CROPPED DETAIL (C,Smoothing4).jpg
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umbel
Posts: 21
Joined: 12.12.2019 08:26

Re: A problem with blurry results around foreground objects

Post by umbel » 13.01.2020 22:16

LS_Vee_61 wrote:
02.01.2020 02:06
Is this correctable in my rendering settings?
I suspect probably not effectively. All stacking methods select for higher contrast and will therefore prefer the edges from specular aberration, particularly when undercorrected spherical aberration occurs beyond the depth of focus and where angles between aperture blades concentrate light. So, if you look through the source images in the stack, it's likely you'll find the halation corresponds to bokeh balls and the orientation of the halation rays matches the position of the aperture blades.

The usual mitigation is to increase the amount of diffusion and structure the diffuser such that the light source appears large as seen from the subject. A good starting point is to seek slightly washed out images in camera or in stack preparation from raw in order to get the desired result after stacking boosts contrast. Since stacking shifts highlights somewhat to the right I usually also shift exposures in the source images somewhat to the left to provide some highlight protection. Since specular hightlights are usually blown this amounts to configuring lighting and worfklow to keep halated areas acceptably small.

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