[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？ u'nQC*iJb  
一下是我的Prescription Data数据： kH8/
8  
GENERAL LENS DATA: 2VzYP~Jg  
5|5p -B  
Surfaces                :                3 IC?(F]$%>  
Stop                    :                1 2RQ-L  
System Aperture         : Object Space NA = 0.12 /,`OF/%  
Glass Catalogs          : Schott H@1}_d  
Ray Aiming              : Paraxial Reference, Cache On C;j&Vbf  
X Pupil shift          :               0 IVY)pS"pR"  
Y Pupil shift          :               0 Re&"Q8I.8  
Z Pupil shift          :               0 gB
~^dv {  
Apodization             : Gaussian, factor =   1.00000E+000 PD&gC88
  
************************************************************* sn"z'=ch  
Effective Focal Length  :        1.639158 (in air at system temperature and pressure) 7Ja*T@ !h  
Effective Focal Length  :        1.639158 (in image space) W.NZ%~|+e/  
************************************************************* }wkY`"  
Back Focal Length       :       -1.061568 FgL892[  
Total Track             :           4.318 =r*Ykd;W|E  
Image Space F/#         :        3.417255 C!|LGzs0  
Paraxial Working F/#    :        2.950535 z:4_f:70  
Working F/#             :        2.961912 G;$;$gM  
Image Space NA          :       0.1670788 K8R>O *~  
Object Space NA         :            0.12 -]+pwZ4g  
Stop Radius             :       0.2398355 z$WLx  
Paraxial Image Height   :               0 u~aRFQ:  
Paraxial Magnification  :               0 Ulx]4;uzf  
Entrance Pupil Diameter :       0.4796709 (|F.3~Amq  
Entrance Pupil Position :               0 k%FA:ms|k  
Exit Pupil Diameter     :        2.511155 *mVg_Kl  
Exit Pupil Position     :        7.420935 H>A6VDu  
Field Type              : Angle in degrees 4(8trD6  
Maximum Field           :               0 /0 4US5En  
Primary Wave            :            1.31 QW$p{ zo  
Lens Units              :   Millimeters >=|p30\b  
Angular Magnification   :               0 4eY?#8  
vaGF(hfTA  
Fields          : 1 kw@^4n+M  
Field Type: Angle in degrees U3N9O.VC  
#        X-Value        Y-Value         Weight &iVdqr1,  
1       0.000000       0.000000       1.000000 ^:]$m;v]  
U2A 82;Z  
Vignetting Factors #,u|*O:  
#       VDX       VDY       VCX       VCY       VAN [ r8 ZAS  
1  0.000000  0.000000  0.000000  0.000000  0.000000 {eV8h}KIl  
s<)lC;#e  
Wavelengths     : 1 m
sM1K1er  
Units: Microns XS">`9o!  
#          Value         Weight f+Sb>$  
1       1.310000       1.000000 }&t>j[  
UhpJGO  
CARDINAL POINTS: ?UZt30|1  

\1Xk[%  
Object space positions are measured with respect to surface 1. hg(<>_~  
Image space positions are measured with respect to the image surface. Vh;zV Y  
The index in both the object space and image space is considered. weSq|f  
b.@a,:"  
                          Object Space         Image Space  D**GC  
W = 1.310000 (Primary) QCF'/G
 
************************************************************ n+Kv^Y`qxO  
Focal Length          :           -1.639015            1.639015 8&)v%TX  
************************************************************ J6AHc"k.  
Focal Planes          :            0.313078           -1.159568 7l=;I%  
Principal Planes      :            1.952094           -2.798584 LWN{  
Anti-Principal Planes :           -1.325937            0.479447 ~DI$O[KpR%  
Nodal Planes          :            1.952094           -2.798584 AQg|lKv  
Anti-Nodal Planes     :           -1.325937            0.479447 `;E/\eG"  
(Z SaAn),  
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