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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Better views than Nikon EII/SE? (1 Viewer)

BruceH said:
Dennis ...... Do you know your own corrected visual acuity? (20/20, 20/22, 20/18, etc). Is this from your own testing or from an eye exam? My distance vision has actually improved with age. Getting older is not all bad!
Click to expand...
I had Lasik surgery on my eyes years ago and they have stayed at 20/20 by my own testing. When you get older there is AMD, Cataracts, and Glaucoma to worry about though.
 
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[email protected] said:
Just like an optical instrument such as a telescope? Interesting.
Click to expand...

Bingo! A YOUNG dark-adapted eye might open to ~f/4. In sunlight, it might get stopped down to around f/11. Let's say the eye is just over 1 inch in diameter—say 27.4mm and the eye is (in bright light) stopped to 2.5mm. 27.4mm divided by 2.5mm = f/10.96:cat:

Cheers,

Bill
 
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