An interesting query/observation has just been posted on a CML -post forum. I would think the defect might be observed whenever excessive mpeg compression is employed.
CML-post:
> I've been getting DVD dailies for this TV series I'm shooting in 35mm,
> and they have this problem of the focus drifting in and out, the lower
> contrast the image is, with soft lighting, the more the focus seems to
> pop in and out.
A filmmaker recently called us in panic mode: the DVD dailies
of his film shot with the Penelope's 2Perf movement prototype
was showing breathing in the gate! Shame and consternation
in the Aaton R&D dept.
Two days later we received the DVD and discoverd the questionable
scenes were the ones showing a lot of moving details (background tree
branches moving in the wind), the foreground seemed to pop in and out of
focus in sync with the branches as if the wind was blowing in
the camera gate...
Explanation which probably applies to your case: the 'Mpeg'
compressor was allocating more space to the moving foliage
than to the static foreground... Bad settings, cheapo compressor,
too high compression ratio, we don't yet know.
Better to carry four dailies DVDs than one containing
a DOP's heart-attack trigger.
CML-post:
> I've been getting DVD dailies for this TV series I'm shooting in 35mm,
> and they have this problem of the focus drifting in and out, the lower
> contrast the image is, with soft lighting, the more the focus seems to
> pop in and out.
A filmmaker recently called us in panic mode: the DVD dailies
of his film shot with the Penelope's 2Perf movement prototype
was showing breathing in the gate! Shame and consternation
in the Aaton R&D dept.
Two days later we received the DVD and discoverd the questionable
scenes were the ones showing a lot of moving details (background tree
branches moving in the wind), the foreground seemed to pop in and out of
focus in sync with the branches as if the wind was blowing in
the camera gate...
Explanation which probably applies to your case: the 'Mpeg'
compressor was allocating more space to the moving foliage
than to the static foreground... Bad settings, cheapo compressor,
too high compression ratio, we don't yet know.
Better to carry four dailies DVDs than one containing
a DOP's heart-attack trigger.