[求助]关于Effective focal length的问题 [复制链接]

  ZEMAX中priscription data会给出系统的许多有用的数据，其中包括effective focal length的数据和主平面位置的数据。但是我发现直接给出的effective focal length数据和根据其定义结合主平面的数据算出来的结果不一致，这时怎么回事？ RK|C*TCnl  
一下是我的Prescription Data数据： $cc]pJy"}  
GENERAL LENS DATA: +g(QF
  
B&cC;Hw  
Surfaces                :                3 }yUZ(k#  
Stop                    :                1 L.>`;`dmY  
System Aperture         : Object Space NA = 0.12 -FwOX~s/'  
Glass Catalogs          : Schott `C,479~J  
Ray Aiming              : Paraxial Reference, Cache On A%pcPzG;  
X Pupil shift          :               0 ^MuO;<<,.  
Y Pupil shift          :               0 @Kp2l<P  
Z Pupil shift          :               0 "Q^Ck7  
Apodization             : Gaussian, factor =   1.00000E+000 Y7= *-  
************************************************************* "+p_{J/P  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) Mc9%s$MT  
Effective Focal Length  :        1.639158 (in image space) 9|fg\C  
************************************************************* Tw=Jc 's  
Back Focal Length       :       -1.061568 L9"V$MO  
Total Track             :           4.318 K%.\@l2Cp  
Image Space F/#         :        3.417255 :2}zovsdj  
Paraxial Working F/#    :        2.950535 FgLV>#)-  
Working F/#             :        2.961912 }PD?x4  
Image Space NA          :       0.1670788 ml\A)8O]j/  
Object Space NA         :            0.12 J&wrBVv1uk  
Stop Radius             :       0.2398355 y^?7de}  
Paraxial Image Height   :               0 >HXT:0  
Paraxial Magnification  :               0 TN4gGky!  
Entrance Pupil Diameter :       0.4796709 ,..&j
+m  
Entrance Pupil Position :               0 J;HkR9<C  
Exit Pupil Diameter     :        2.511155 6Gwk*%sb  
Exit Pupil Position     :        7.420935 ^ 14U]<  
Field Type              : Angle in degrees uL`
;KD  
Maximum Field           :               0 :>]=YE  
Primary Wave            :            1.31 CtfI&rb[  
Lens Units              :   Millimeters %N04k8z  
Angular Magnification   :               0 g?qm >X  
!ffdeWHR  
Fields          : 1 f.4r'^  
Field Type: Angle in degrees (w}iEm\b  
#        X-Value        Y-Value         Weight u,I_p[`E  
1       0.000000       0.000000       1.000000 J4&d6[
40  
( $A0b  
Vignetting Factors 1:(qoA:  
#       VDX       VDY       VCX       VCY       VAN q,(U8
  
1  0.000000  0.000000  0.000000  0.000000  0.000000 ,3=|a|p  
9KkxUEk
W  
Wavelengths     : 1 x\T 9V~8a  
Units: Microns W1fEUVj  
#          Value         Weight YBehyx2eK  
1       1.310000       1.000000 Dk[m)]w\  
BIqZg$  
CARDINAL POINTS:  Y[#EFM  
;EDc1:  
Object space positions are measured with respect to surface 1. K-vG5t0$\/  
Image space positions are measured with respect to the image surface. &NM.}f  
The index in both the object space and image space is considered. m^I+>Bp/:  

ssj(-\5  
                          Object Space         Image Space `lygJI?H+{  
W = 1.310000 (Primary) 46OYOa  
************************************************************ >]s\%GO  
Focal Length          :           -1.639015            1.639015 ,T&=*q  
************************************************************ GG<{n$h  
Focal Planes          :            0.313078           -1.159568 TrD2:N}dI  
Principal Planes      :            1.952094           -2.798584 [$:M/5y9  
Anti-Principal Planes :           -1.325937            0.479447 M$iDaEu-  
Nodal Planes          :            1.952094           -2.798584 BWRAz*V  
Anti-Nodal Planes     :           -1.325937            0.479447 Jas=D  
1$mxMXNsJ  
我用*号，标出了需要注意的地方，请高手指教！

各位指点一下吧，自己顶起来！

帮顶！！！！！！！！！！！！！！1

等待高手帮忙吧 我也不会!

看的我头晕了,可能是感冒的缘故吧,以后有机会再探讨

我也不会先看看再说!~

慢慢理解