I've been meaning to ask this question, so here it is...

[diver 85]

A little background on the asking of it 1st: I read all the time here people talking about different lenses for (UW) cameras etc & they use the abbreviation D. My curiosity kicks in now, does anyone(without looking it up of course..lol) know what a D. is & 'how it's used in optics???

Come on all you P.O.(physiological optics) majors, lets here it....

 

[cdennyb]

diopter. look it up.

 

[Diver Dennis]

I use a "wet" Diopter called a Woody for shooting macro.

 

[diver 85]

diopter. look it up.

Trust me, I know what it is....have had 7 post graduate P.O. courses .....In particular, it's (our) unit of power, recipical meters, which means what??...........

 

[cdennyb]

The definition I recall is something like the focal length at 30-some inches, probably a meter 'cause it's always metric in optics is the power of 1 diopter, and people I chat with about underwater photog explain you can change the diopter lens you use to compensate for the magnification of the water refraction. You know, everything looks bigger underwater thing. Someone else out there will no doubt make me look stupid with their vast knowledge of what I'm trying to say. Have at it.

db