[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？ oJcDs-!  
一下是我的Prescription Data数据： x-Kq=LFy.  
GENERAL LENS DATA: 8E m X  
;^9Ao>(?y  
Surfaces                :                3 5Iv3B|u  
Stop                    :                1 y5d=r]_S:  
System Aperture         : Object Space NA = 0.12 JF%eC}[d  
Glass Catalogs          : Schott O>Vb7`z0<  
Ray Aiming              : Paraxial Reference, Cache On c~@Z  
X Pupil shift          :               0 lG\6z"K  
Y Pupil shift          :               0 QEe\1>1"&  
Z Pupil shift          :               0 /B$9B  
Apodization             : Gaussian, factor =   1.00000E+000 qno8qF*  
************************************************************* Op&i6V}<s  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) R6^U9fDG  
Effective Focal Length  :        1.639158 (in image space) _I$\O5  
************************************************************* )jM' x&Vg  
Back Focal Length       :       -1.061568 i@=0fHiZQ  
Total Track             :           4.318 bbDl?m&bq  
Image Space F/#         :        3.417255 5J d7<AO_  
Paraxial Working F/#    :        2.950535 #1INOR9  
Working F/#             :        2.961912 W| z djb  
Image Space NA          :       0.1670788 rOt`5_2f  
Object Space NA         :            0.12 7oj ^(R,  
Stop Radius             :       0.2398355 or?@Ti;  
Paraxial Image Height   :               0 ~i)m(65:  
Paraxial Magnification  :               0 HN/ %(y  
Entrance Pupil Diameter :       0.4796709 *hhPCYOm  
Entrance Pupil Position :               0 ~uF%*  
Exit Pupil Diameter     :        2.511155 y4%u</  
Exit Pupil Position     :        7.420935 AY{-Hf&  
Field Type              : Angle in degrees Md~% e'  
Maximum Field           :               0 b51{sL  
Primary Wave            :            1.31 mVJW"*}8  
Lens Units              :   Millimeters N7S?m@  
Angular Magnification   :               0 X@;o<2^  
FtaO@5pS54  
Fields          : 1 y\=(;]S'  
Field Type: Angle in degrees c-|~ABtEpX  
#        X-Value        Y-Value         Weight >zYO1.~  
1       0.000000       0.000000       1.000000 [(Z sQK  
*Y4h26  
Vignetting Factors svt%UE|_:$  
#       VDX       VDY       VCX       VCY       VAN 5Ocd2T'  
1  0.000000  0.000000  0.000000  0.000000  0.000000 mlIX>ss|7B  
gk"0r\Eq  
Wavelengths     : 1 K+9oV[DMs  
Units: Microns ~hubh!d=  
#          Value         Weight X67.%>#3  
1       1.310000       1.000000 XCQS_'D  
D}n&`^1X+  
CARDINAL POINTS: K+3dwQo  
c,ccavv{I  
Object space positions are measured with respect to surface 1. yv.Y-c=  
Image space positions are measured with respect to the image surface. (&n4^tJ+_  
The index in both the object space and image space is considered.  tCT-cs

 
s0,\[rM  
                          Object Space         Image Space ")J\} $r  
W = 1.310000 (Primary) q4].C|7  
************************************************************ L@ ,-V  
Focal Length          :           -1.639015            1.639015 G8c 8`~t  
************************************************************ (~YFm"S  
Focal Planes          :            0.313078           -1.159568 %9|}H [x  
Principal Planes      :            1.952094           -2.798584 (
K5w0  
Anti-Principal Planes :           -1.325937            0.479447 -7GF2 @  
Nodal Planes          :            1.952094           -2.798584 .C]V==z`[4  
Anti-Nodal Planes     :           -1.325937            0.479447 ]SNA2?q  
9fk@C/$  
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