[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？ t-Wn@a  
一下是我的Prescription Data数据： 1"k@O)?JP  
GENERAL LENS DATA: }!LYV  
9[!
Hz)|X  
Surfaces                :                3 (ni$wjq=z^  
Stop                    :                1 v\c3=DbO  
System Aperture         : Object Space NA = 0.12 aZRgd^4  
Glass Catalogs          : Schott $4"OD"Z Cq  
Ray Aiming              : Paraxial Reference, Cache On 3kMiC$  
X Pupil shift          :               0 D-.>Dw:  
Y Pupil shift          :               0 ,]MX&]  
Z Pupil shift          :               0 d~8Q)"6 [  
Apodization             : Gaussian, factor =   1.00000E+000 \WT
g0b[  
************************************************************* 2gGJ:,RC$  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) G-qxQD1wK  
Effective Focal Length  :        1.639158 (in image space) ]V_9[=%  
************************************************************* k|V{jBG"@  
Back Focal Length       :       -1.061568 4)ISRR  
Total Track             :           4.318 8yo9$~u;  
Image Space F/#         :        3.417255 F-Ea85/K@4  
Paraxial Working F/#    :        2.950535 aE"t['  
Working F/#             :        2.961912 Km?i{TW  
Image Space NA          :       0.1670788 :PLsA3[}  
Object Space NA         :            0.12 l>ttxYBa<d  
Stop Radius             :       0.2398355 ,y.0Cb0  
Paraxial Image Height   :               0 M3V[p9>  
Paraxial Magnification  :               0 DM&"oa50  
Entrance Pupil Diameter :       0.4796709 `y\:3bQ4  
Entrance Pupil Position :               0 ^:]
,JN k  
Exit Pupil Diameter     :        2.511155 (<CLftQKg  
Exit Pupil Position     :        7.420935 bk<3oI  
Field Type              : Angle in degrees _#_Ab8#  
Maximum Field           :               0 !EFd-fk  
Primary Wave            :            1.31 %(E6ADB  
Lens Units              :   Millimeters $lqV(s  
Angular Magnification   :               0 =mZw71,  
k"Is.[I?^  
Fields          : 1 tx@Q/ou`\P  
Field Type: Angle in degrees ~AO0(Lp  
#        X-Value        Y-Value         Weight /sai}r1  
1       0.000000       0.000000       1.000000 $`  
5s>9v  
Vignetting Factors +a|4XyN  
#       VDX       VDY       VCX       VCY       VAN YS]RG/'  
1  0.000000  0.000000  0.000000  0.000000  0.000000 Ov9.qNT  
CUG6|qu  
Wavelengths     : 1 $W09nz9?  
Units: Microns f,1rmX1  
#          Value         Weight ji2#O.  
1       1.310000       1.000000 YJ
9_cA'A  
0nS6<:  
CARDINAL POINTS: jsR1jou6  
^uj+d"a)  
Object space positions are measured with respect to surface 1. ?`vb\K<5H;  
Image space positions are measured with respect to the image surface. m$^7sFD$  
The index in both the object space and image space is considered. iqU}t2vFrj  
C@[:}ZGMV  
                          Object Space         Image Space 6Z"%vrH  
W = 1.310000 (Primary) E'ZWSpP  
************************************************************ uC3$iY:_e  
Focal Length          :           -1.639015            1.639015 ;2iZX=P`n  
************************************************************ ;V;4#  
Focal Planes          :            0.313078           -1.159568 1$|z%(  
Principal Planes      :            1.952094           -2.798584 MMf6QxYf  
Anti-Principal Planes :           -1.325937            0.479447 y`BLIEI  
Nodal Planes          :            1.952094           -2.798584 uPqPoI>N!  
Anti-Nodal Planes     :           -1.325937            0.479447 d+^;kse  
%:y-"m1\u$  
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