Why is Focal Length in mm (cm and inches), rather then Angle of View?

Bill Burk said:

Does light then emanate from the retina and travel towards the source?

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Redeye...

Nodda Duma said:

The convention as accepted in the optical engineering and design community is "Field of View".

You image in two-dimensional space (field), not one-dimensional space (an angle).

Look up MIL-STD-1241A, which captured the industry standard optical terms and definitions.

http://everyspec.com/MIL-STD/MIL-STD-1100-1299/MIL_STD_1241A_867/

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Help me out, I can't find "Camera" or "Camera Lens" in that list.

ic-racer said:

Help me out, I can't find "Camera" or "Camera Lens" in that list.

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That should tell you something about how non-specific those terms are. This was an optical definition standard, not a photography terms standard. So use it as a reference for technical terms related to optics. Consider also the standard was drafted with a certain level of intelligence assumed of the reader. The standard was considered a companion to MIL-HDBK-141.

Review the "Lens, ---" terms, as well as the definition for "Objective"

I do have question for richard ide

Hey, richard ide. You said that you have Wild Reprogon...
I did get one from some one in two parts. (on one part of lans is written,WILD Reprogon 1:5.6 f=149,43) How do I assemble it together? Is just "lens on lens" or is something in between? I will be really happy if I can put it together... this massive piece thing. So I hope you can help me out. Tnx! Tnx!