Fil:FocalLength.png
Fuld opløsning (1.280 × 1.024 billedpunkter, filstørrelse: 104 KB, MIME-type: image/png)
Denne fil er fra Wikimedia Commons. Beskrivelsen af filen fra Commons er gengivet nedenfor. |
Beskrivelse
BeskrivelseFocalLength.png | Demonstrating the concept of focal length for a convex, spherical lens: Light beams entering from the left gets refracted twice before focusing at approximately distance f to the right of the lens. |
Dato | 2. marts 2006 (original upload date) |
Kilde | No machine-readable source provided. Own work assumed (based on copyright claims). |
Forfatter | No machine-readable author provided. Peo~commonswiki assumed (based on copyright claims). |
Licensering
- Du må frit:
- at dele – at kopiere, distribuere og overføre værket
- at remixe – at tilpasse værket
- Under følgende vilkår:
- kreditering – Du skal give passende kreditering, angive et link til licensen, og oplyse om der er foretaget ændringer. Du må gøre det på enhver fornuftig måde, men ikke på en måde der antyder at licensgiveren godkender dig eller din anvendelse.
- deling på samme vilkår – Hvis du bearbejder, ændrer eller bygger videre på dette værk, skal du distribuere dine bidrag under den samme eller en kompatibel licens som originalen.
POV-Ray code
This image was rendered using POV-Ray for Windows version 3.6 and the scene description code below. Note that the POV-Ray installation needs to have access to the font file "timesbi.ttf" for rendering the bold italic "f" in the image.
If rendered as shown, this code will produce the above image, but by replacing the #switch (1) in the 13th line by a #switch (2), you get the image ShortFocalLength.png.
/*
================================================
Demonstrating ocal length for a convex lens
------------------------------------------------
Created by Søren Peo Pedersen - see my user page
at http://da.wikipedia.org/wiki/Bruger:Peo
================================================
*/
#declare IndexOfRefraction=1.66; // Simulated index of refraction
#declare LineWidth=0.02; // Width of light beam lines
#switch (1) // edit to 1 for long, 2 for short focal length
#case (1)
#declare LR=10;
#declare VisF=1;
#break
#case (2)
#declare LR=4.4;
#declare VisF=0;
#break
#end
#declare FL=1/(IndexOfRefraction-1)/(2/LR);
#declare LS=sqrt(LR*LR-5.29)-.05;
#macro DashedLine(L) // White dashed line for annotations
union {
#local cnt=0;
#while (cnt<L)
box {<-.03,cnt/2,-.02>,<.03,cnt/2+.25,-.021>}
#local cnt=cnt+1;
#end
}
#end
#macro Beam(Shift) // Renders one of the nine beams
#local pX1=LS-sqrt(LR*LR-Shift*Shift);
#local VI1=asin(Shift/LR);
#local VO1=-asin(Shift/LR/IndexOfRefraction);
#local LLa=-tan(VI1+VO1);
#local LLb=(Shift-LLa*pX1);
#local ALa=1+LLa*LLa;
#local ALb=(2*LS+2*LLa*LLb);
#local ALc=LS*LS+LLb*LLb-LR*LR;
#local ALD=ALb*ALb-4*ALa*ALc;
#local pX2=(-ALb+sqrt(ALD))/(2*ALa);
#local pY2=sqrt(LR*LR-(pX2+LS)*(pX2+LS))*select(LLa,1,1,-1);
#local Vud=atan(pY2/(pX2+LS));
#local VI2=Vud+VO1+VI1;
#local VO2=-asin(sin(VI2)*IndexOfRefraction);
#local DIR=Vud+VO2;
#local pX3=pX2+50*cos(DIR);
#local pY3=pY2+50*sin(DIR);
sphere_sweep {
linear_spline,4,
<-50,Shift,0>,LineWidth
<pX1,Shift,0>,LineWidth
<pX2,pY2,0>,LineWidth
<pX3,pY3,0>,LineWidth
pigment {color rgb<1,.95,.8>}
finish {ambient 1 diffuse 0}
no_shadow no_reflection
translate <0,0,-LineWidth>
scale <1,1,.5>
}
#end
#if (VisF != 0) // Include annotation of "f" length in image?
union {
#object {DashedLine(11) translate <0,-2.8,0>}
#object {DashedLine( 7) translate <FL-pi/LR,-2.8,0>}
text {ttf "timesbi.ttf"
"f",.1,0
translate <(FL-pi/LR)/2-.3,-3,0>
}
triangle {<0,-2.7,0>,<.5,-2.5,0>,<.5,-2.9,0>}
box {<.5,-2.66,.001>,<(FL-pi/LR)/2-.3,-2.74,0>}
triangle {<FL-pi/LR,-2.7,0>,<FL-.5-pi/LR,-2.5,0>,<FL-.5-pi/LR,-2.9,0>}
box {<FL-.5-pi/LR,-2.66,.001>,<(FL-pi/LR)/2+.3,-2.74,0>}
pigment {color rgb 1} finish {ambient 1 diffuse 0}
}
#end
intersection { // The lens itself
sphere {<-LS,0,0>,LR}
sphere {< LS,0,0>,LR}
cylinder {<-8,0,0>,<8,0,0>,2.3}
plane {<0,0,-1>,0}
pigment {color rgbt <.8,1,.9,.7>}
finish {phong 1 reflection .1 ambient .5}
interior {ior IndexOfRefraction}
}
#object {Beam( 2.0)} // Beams: The number
#object {Beam( 1.5)} // in parenthesis are
#object {Beam( 1.0)} // the Y coordinates
#object {Beam( 0.5)} // for each beam of
#object {Beam( 0)} // light coming in
#object {Beam(-0.5)} // from the left
#object {Beam(-1.0)}
#object {Beam(-1.5)}
#object {Beam(-2.0)}
camera {
location <FL/2,0,-500>
look_at <FL/2,0,0>
angle 1
}
light_source {<100,100,-100> color rgb 1}
Elementer som er med i denne fil
afbilder
2. marts 2006
image/png
Filhistorik
Klik på en dato/tid for at se filen som den så ud på det tidspunkt.
Dato/tid | Miniaturebillede | Dimensioner | Bruger | Kommentar | |
---|---|---|---|---|---|
nuværende | 2. mar. 2006, 14:41 | 1.280 × 1.024 (104 KB) | Peo~commonswiki | Demonstrating the concept of focal length for a convex, spherical lens: Light beams entering from the left gets refracted twice before focusing at approximately distance ''f'' from the lens. |
Filanvendelse
Den følgende side bruger denne fil:
Global filanvendelse
Følgende andre wikier anvender denne fil:
- Anvendelser på pl.wiktionary.org