Why Does a Fresnel Lens Create an Upright Image in a Galilean Telescope Setup?

[soomro]

I have a Fresnel lens which is equal-ant to a Plano Convex lens, Consider object on one side and my eye is on the other side of the lens, when I see through that lens I always do see an upright image of same size even if I flip the lens, Can anyone please tell me geometric optics equal-ant of this configuration.


eye--------200-500mm di ---------- FRESNEL lens ------------- 500mm dis-------------OBJ

 

[UltrafastPED]

Considering only geometric optics, plano-convex lenses work the same when viewed from either side.

There are slight differences for wave optics, but they are seldom noticeable except in the context of lasers and the minimization of phase errors.

The best way to estimate the focal length is allow sunlight to fall on the lens, and measure the distance when it forms an image.

 

[soomro]

MY question is why I do see upright image with naked eye if eye look from other side of lens, while if I place screen on other side I do see inverted image which it should be.

If I do use simple geometric optics Its will be 1-OBJ 2-LENS and 3-Image, but if there is no screen on image plan & I see it with naked eye I do always see upright image.

 

[UltrafastPED]

I'm glad that you clarified your question!

See http://www.physicsclassroom.com/class/refrn/Lesson-5/Converging-Lenses-Object-Image-Relations