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10-25-2009, 10:51 PM   #1
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What is "Dopler Magnifying Lens"?

Hi,

Who know what is "Dopler Magnifying Lens" and what is it made for?

Regards.

Malsi

10-26-2009, 03:27 AM   #2
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Perhaps you mean gravity lenses?

It is the only thing I can think off, where the Doppler effect is used to measure light frequency shift.

Objects like planets and stars can act like a lens, bending the light around itself, of objects that lie behind them, in a straight line of the observer.
This bending of light works like a lens.

The result of this is used as an indirect detection method to find far away planets, we cannot see.
In fact the light of a star will have variations in its colours when a planet passes in between earth and the star.

There must be forum members that understand this topic much better than I do....

I guess you must be after something completely different.

- Bert

Last edited by bymy141; 10-26-2009 at 11:21 AM.
10-26-2009, 07:48 AM   #3
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Perhaps you mean diopter magnifying lens?

Diopter is a measure of a lens' focal length;

diopter=1000/focal_length_mm

So a 50mm lens is a 20 diopter lens.

Large diopter means large magnification.

If a lens of D diopters is put in front of a lens of focal length F, the combination has a magnification of D*F /1000 for F in millimeters.

Dave in Iowa
10-26-2009, 08:08 PM   #4
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There are two common situations where people talk about "diopters". One is viewfinders - including accoessories you attach to the back of the camera to enhance the viewfinder in some way - where there is often a diopter adjustment to make sure the viewfinder matches your vision. Then there are so-called "closeup lenses" - filters that attach to the front of lenses to help them focus closer, so you can take really close up pictures. Like reading glasses for your camera.

10-27-2009, 12:26 AM   #5
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Original Poster
Hi,

Thank you very much for your anwsers... I will need to find my old lessons . I've just bought a K10D (I will receive it this week I think) and it is included in the package. I've attached the photo where they are (I think ), close to the filters and SD cards.

Regards.

Malsi
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10-27-2009, 05:52 AM   #6
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Yes, those are diopter lenses. They screw on to the camera lens to reduce focusing distance, and increase magnification.
+1 is the weakest, +2, 3, 4 gradually increase in power.
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