[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？ ]oKHS$W9  
一下是我的Prescription Data数据： k40`,;}9  
GENERAL LENS DATA: R l)g[s  
`a@YbuLd  
Surfaces                :                3 v5W-f0Jo  
Stop                    :                1 ;20sh^~  
System Aperture         : Object Space NA = 0.12 Jn20^YG  
Glass Catalogs          : Schott 6)~7Uf:<v  
Ray Aiming              : Paraxial Reference, Cache On ] B>.}  
X Pupil shift          :               0 LE g#W  
Y Pupil shift          :               0 c3O&sa V!  
Z Pupil shift          :               0 U \F ?{/  
Apodization             : Gaussian, factor =   1.00000E+000 gi8f)MNP?~  
************************************************************* bq{eu#rQJ  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) 1Q$/L+uJ5  
Effective Focal Length  :        1.639158 (in image space) A!a.,{fZ  
************************************************************* WH.3  
Back Focal Length       :       -1.061568 bFJ>+ {#  
Total Track             :           4.318 T t
$] [  
Image Space F/#         :        3.417255 $8Gj9mw4e'  
Paraxial Working F/#    :        2.950535 = @lM*  
Working F/#             :        2.961912 y!~ }7=  
Image Space NA          :       0.1670788 |sAl k,8s  
Object Space NA         :            0.12 )c.!3n/pb  
Stop Radius             :       0.2398355 ~{t<g;F  
Paraxial Image Height   :               0 3.Jk-:u %m  
Paraxial Magnification  :               0 X//=OpS`  
Entrance Pupil Diameter :       0.4796709 "lB%"}  
Entrance Pupil Position :               0 i8=+<d  
Exit Pupil Diameter     :        2.511155 1#|qT7  
Exit Pupil Position     :        7.420935 QF$s([  
Field Type              : Angle in degrees t~Qj$:\  
Maximum Field           :               0 UDlM?r:f  
Primary Wave            :            1.31 [u^~ND'  
Lens Units              :   Millimeters 8,)<,g-/=  
Angular Magnification   :               0 QGnUPiD
^  
yxi*4R  
Fields          : 1 +[[^W;<.l  
Field Type: Angle in degrees 4!-/m7%eF  
#        X-Value        Y-Value         Weight </2Cn@  
1       0.000000       0.000000       1.000000 m=60a@o]  
HHT8_c'CC#  
Vignetting Factors ?',GRaD  
#       VDX       VDY       VCX       VCY       VAN {@[#0gPH  
1  0.000000  0.000000  0.000000  0.000000  0.000000 #d$lN}8  
$ou/ Fn  
Wavelengths     : 1 ./
CDW  
Units: Microns :,.HJ[Vg&  
#          Value         Weight ;S'1fci6  
1       1.310000       1.000000 MwaRwk;  
Ys<z%  
CARDINAL POINTS: 1
;Uc-<  
oW6b3Q/B  
Object space positions are measured with respect to surface 1. B_"PFWwg  
Image space positions are measured with respect to the image surface. hwSxdT6  
The index in both the object space and image space is considered. 43*;"w=  
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                          Object Space         Image Space cvjZ$Fcc%(  
W = 1.310000 (Primary) VwT&A9&{8  
************************************************************ ^$y`Q@-9  
Focal Length          :           -1.639015            1.639015 _:KeSskuO  
************************************************************ 96%N  
Focal Planes          :            0.313078           -1.159568 5m?9O7Pg  
Principal Planes      :            1.952094           -2.798584 )qRE['
M  
Anti-Principal Planes :           -1.325937            0.479447 %Lp#2?*  
Nodal Planes          :            1.952094           -2.798584 88l{M[B2  
Anti-Nodal Planes     :           -1.325937            0.479447 `_
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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