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AhamB
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Re: NEX Images Thread


FlyPenFly wrote:
onion ring bokeh which I see in a lot of Sigma lenses is circles within the bokeh circles due to poor cementing.

No, \"onion rings\" are due to aspherical elements, not due to poor cementing.
See page 32 of the Zeiss article on bokeh and DOF.
And some discussion about it in this thread https://www.fredmiranda.com/forum/topic/880700/
Edit: found a thread opened by you with examples of onion rings: https://www.fredmiranda.com/forum/topic/1012875/


Sep 22, 2011 at 02:56 PM
AhamB
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Re: NEX Images Thread


FlyPenFly wrote:
onion ring bokeh which I see in a lot of Sigma lenses is circles within the bokeh circles due to poor cementing.

No, \"onion rings\" are due to aspherical elements, not due to poor cementing.
See page 32 of the Zeiss article on bokeh and DOF.
And some discussion about it in this thread https://www.fredmiranda.com/forum/topic/880700/


Sep 22, 2011 at 02:52 PM
AhamB
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Re: NEX Images Thread


FlyPenFly wrote:
onion ring bokeh which I see in a lot of Sigma lenses is circles within the bokeh circles due to poor cementing.

No, \"onion rings\" are due to aspherical elements, not due to poor cementing.

edit: silly typo


Sep 22, 2011 at 02:46 PM
AhamB
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Re: NEX Images Thread


FlyPenFly wrote:
onion ring bokeh which I see in a lot of Sigma lenses is circles within the bokeh circles due to poor cementing.

No, \"onion rings\" are due to apsherical elements, not due to poor cementing.


Sep 22, 2011 at 01:16 PM





  Previous versions of AhamB's message #9939897 « Sony (APS-C) Images Thread »