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how do binos/our eyes do this ...? (1 Viewer)

jape

Well-known member
as a beginner i am still amazed at the properties binos add to our eyes! more than magnification and light gathering today i noticed another phenomenon.

it is lowish light, grey and raining yet still enough that a backlit bird 20 metres away in tree tops can be identified, in this case, as greenfinch using 8x25.

however, the window i am looking through is covered in rain drops and in the bino view i see none. not even a blur but perhaps a slight general fade or overall very faint grey. i am not even sure that is related as the day is dull.

so how does this happen, the bins cant ignore what is there but they see through the drops which to the eye are bright black and white. the focus wont pull back to them as they are too close to the bins but how does it 'ignore' them when they are physically present! or does the eye do the adjustment?
 
testing as best i am able : it seems two factors at least, first the lack of focus and relative size of rain drops means they become a pale blur, secondly the eye does NOT register the grey blurs at same view that the phone camera does, so physiological.

IMG_20180402_090301_crop_460x460.jpg

IMG_20180402_090517-1024x1820.jpg
 
Binastro is correct as usual. You cannot see the raindrops because they are so much out of focus due to being so far outside the field of view but they are still there contributing a faint fuzziness.

Lee
 
I see the raindrops in photo 1.
It depends on the camera sensor size, lens focal length and f stop.

Maybe photo 1 is with a small sensor compact or even a camera phone, which has a very small sensor, (although I don't have one, so don't know the sensor size).

That is why people use full frame cameras and fast lenses fully open for portraits, to isolate the subject with focus on the eyes.

P.S.
What one notices in photo 1 is that each raindrop acts as a lens and inverts the image, with the bright sky below.

The area occupied by the raindrops on the window is small, maybe 10%?? of the area photographed. This causes the out of focus greyness.

Raindrops on leaves with the sun shining can produce lovely artificial stars that can be used for star testing in daylight.
 
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yeah, im not arguing with any explanation. need to learn more.
pic 1 is camera on phone, all i have but same as eye sees, rain drops.
pic 2 is same phone camera through bins, you can see the rain but grey blurs of course
however, eye through same bins, same place, i dont see the grey blurs at all and i tried different angles and places.
where camera or camera through bins shows rain drops as sharp or if magnified as grey blurs, through binos the eye doesnt even see the grey blurs. so difference is between eye (or brain?) and camera.
 
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