Transcript pptx
Recipes fo Optical Effect
System Design II
Real-time Rendering of Physically Based Optical Effects in Theory and Practice
Yoshiharu Gotanda
tri-Ace, Inc.
Real Lens Structure
• Useful to achieve photo-realistic (physically
based) optical effects
– Implementation for
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Optical vignetting
Focus breathing
Bokeh with aberrations and distortions
Lens ghosts
Physical Limitations
• Lens structure also gives us limitations for
lens parameters
– Focus distance
– F-number
– Zoom
Lens Database
• Lens database is useful for both
implementations and parameter limitations
– The limitations prevent setting incorrect
camera parameters
• Too small F-numbers (e.g. F0.x)
• Too close focus distance with a big format sensor
Lens Database
• Our lens database
approximates a lot of
parameters
struct LensParameter
{
string
u8
szName[64];
nAppertureAngleNumber;
f32
fDesignedFilmSize;
f32
f32
f32
fMinFStop;
fMaxFStop;
fFStopZoom;
f32
fMinFocusDepth;
f32
f32
fMinProjectionDistance;
fMaxProjectionDistance;
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};
----------------Vignetting Distance
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--------------- <----------->
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Entrance
|| Open Ap ||Vignetting||
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Size
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Size
||Size
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--------------<-Frange Back ->
----------------^Iris
<- Iris Distance ->
<------------ Entrance Distance ------------>
f32
f32
f32
f32
f32
f32
f32
f32
f32
f32
fEntranceDistance;
fEntranceSize;
fApertureDistance;
fOpenApertureSize;
fVignettingDistance;
fVignettingSize;
fFrangeBack;
fNaturalVignettingPower;
fFocusingZoomAjustiveRateWIDE;
fFocusingZoomAjustiveRateTELE;
u8
u8
f32
f32
f32
nFocalLengths;
nApertures;
afFocalLength[5];
afAperture[5];
afVignettingEV[5][5];
Lens Database
• Our lens database has
a lot of lenses
– This table shows some
lenses which the
database includes
Lens Database Examples
Kanon EF24mm F1.4L USM
Kanon EF300mm F2.8L IS USM
Kanon EF24-70mm F2.8L USM
Kanon EF100mm F2.8 macro
Kanon EF28-300mm F3.5-5.6L IS
USM
AskaNP EF28-300mm F2.0
AskaNP EF14-1200mm F1.4
AskaNP EF8-2400mm F1.0
Real Lenses?
• Are these lenses
unrealistic?
– If there are,
• Very expensive
• Very heavy and big
Lens Database Examples
Kanon EF24mm F1.4L USM
Kanon EF300mm F2.8L IS USM
Kanon EF24-70mm F2.8L USM
Kanon EF100mm F2.8 macro
Kanon EF28-300mm F3.5-5.6L IS
USM
AskaNP EF28-300mm F2.0
AskaNP EF14-1200mm F1.4
AskaNP EF8-2400mm F1.0
Unrealistic Lenses
• Real lenses (for 35mm format) are
sometimes not easy to use
– Artists may feel that it is too costly to pick up
an appropriate lens for a scene
• It is a similar situation to a real lens
interchangeable camera!
Unrealistic Lenses
• Lens database is still required to
implement physically based optical effects
– Virtual lenses
– Usability vs. physical plausibility
Virtual Lenses
Still realistic
Less realistic,
more useful
Awesome!
I want this!
Lens Database Examples
Kanon EF24mm F1.4L USM
Kanon EF300mm F2.8L IS USM
Kanon EF24-70mm F2.8L USM
Kanon EF100mm F2.8 macro
Kanon EF28-300mm F3.5-5.6L IS
USM
Lens configuration (parameter limitations)
also follows this reality rule
AskaNP EF28-300mm F2.0
AskaNP EF14-1200mm F1.4
AskaNP EF8-2400mm F1.0
Conclusion
• Lens database is useful for both
implementation and parameter limitations
– Physically plausible implementation for optical
effects
– To prevent setting strange parameters
– Real lenses are sometimes too inconvenient
Acknowledgements
• Masaki Kawase
• Masanori Kakimoto
• Kristian Spoerer