[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？ aR iD}P*V  
一下是我的Prescription Data数据： ^yO+-A2zC  
GENERAL LENS DATA: "kLu]M<  
Ft7{P.g  
Surfaces                :                3 b'D|p/)m0S  
Stop                    :                1 ,qx;
kJJ  
System Aperture         : Object Space NA = 0.12 0@FZQ$-  
Glass Catalogs          : Schott 8{m5P8w'  
Ray Aiming              : Paraxial Reference, Cache On l5> H\  
X Pupil shift          :               0 dG
6 G  
Y Pupil shift          :               0 x
q?9w$  
Z Pupil shift          :               0 tD G[}j  
Apodization             : Gaussian, factor =   1.00000E+000 mfYY?]A*+  
************************************************************* =@98Gl9!  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) C^}2::Qu  
Effective Focal Length  :        1.639158 (in image space) X~aD\%kC7  
************************************************************* j}0W|*  
Back Focal Length       :       -1.061568 `N+A8  
Total Track             :           4.318 U_/sY9gz(  
Image Space F/#         :        3.417255 Hs%;uyI@$  
Paraxial Working F/#    :        2.950535
]h(}%fk_  
Working F/#             :        2.961912 w]4=uL6  
Image Space NA          :       0.1670788 (*.t~6c?5  
Object Space NA         :            0.12 ?2Q9z-$  
Stop Radius             :       0.2398355 e<Hbm  
Paraxial Image Height   :               0 :8}
iZ.  
Paraxial Magnification  :               0 6Un61s  
Entrance Pupil Diameter :       0.4796709 we6kV-L.  
Entrance Pupil Position :               0 ]et4B+=i  
Exit Pupil Diameter     :        2.511155 ^8,Y1r9`$  
Exit Pupil Position     :        7.420935 nqG9$!k^t  
Field Type              : Angle in degrees )c'5M]V  
Maximum Field           :               0 Pj4WWKX  
Primary Wave            :            1.31 0P(U^rkR~  
Lens Units              :   Millimeters V3<baxdE  
Angular Magnification   :               0 o"O=Epg  
TM|M#hMS  
Fields          : 1 ohK_~  
Field Type: Angle in degrees LX%K*nlj  
#        X-Value        Y-Value         Weight f0uzoeL<%  
1       0.000000       0.000000       1.000000 CNC3">Dk~9  
hXsd12  
Vignetting Factors %/l9$>{  
#       VDX       VDY       VCX       VCY       VAN W/(D"[:l%  
1  0.000000  0.000000  0.000000  0.000000  0.000000 |5uvmK  
RC_w 1:h  
Wavelengths     : 1 rJ LlDKP-(  
Units: Microns d(.e%[`  
#          Value         Weight $T\W'WR>  
1       1.310000       1.000000 ~9&#7fU  
t>D|1E"  
CARDINAL POINTS: &RRHmJI:  
9:|z^r  
Object space positions are measured with respect to surface 1. "<c^`#CWuO  
Image space positions are measured with respect to the image surface. AXUSU(hU  
The index in both the object space and image space is considered. Eei"baw/  
{1RI!#[\  
                          Object Space         Image Space {K\l3_=5qb  
W = 1.310000 (Primary) C- Aiv@@<=  
************************************************************ Fai_v{&?  
Focal Length          :           -1.639015            1.639015 _[zZm*  
************************************************************ uFseO9F.2  
Focal Planes          :            0.313078           -1.159568 Gp0H[-oF  
Principal Planes      :            1.952094           -2.798584 `1|#Za~e  
Anti-Principal Planes :           -1.325937            0.479447 !PQ%h/ix  
Nodal Planes          :            1.952094           -2.798584 .\r=1HZ3  
Anti-Nodal Planes     :           -1.325937            0.479447 U} EaV<  
;x 9_  
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