I have just been roasting my little grey cells with the formulae below
Excel: =TAN(RADIANS(B/2))*(A*2)
Lotus 1-2-3: @TAN(@DEGTORAD(B/2))*(A*2)
In the spreadsheet 'A' is the focal length in mm and 'B' is the angle of view in degrees.
You need two rows and four columns, the formula is in the third and the output is in the fourth.
You format the fourth cloumn to be a number without any decimal places.

Quote:

On 2004-06-01 06:09, RichS wrote: [ And remember, spreadsheet calculate in radians, not degrees!

What I did was add a constant. This way the user can input degrees and the formula still gets radians. Just one constant to add

0.0174532925

Nick

Hey, I'm such a Neanderthal, I still have a slide rule, too. Only mine's a Pickett: 100% stainless steel. Pickett slide rules went to the moon, you know. (Along with Has***blad and Tang).

I don't know if you guys know this, so shout at me if I'm stating the obvious-- I just discovered this a little while ago. You can use Google as a calculator, and it does trig functions too. I think it defaults to radians, but if you key in, for example, tan(45 degrees), you'll get the right answer.

Radians. Hell, I can't even remember when I last thought about radians.

And another thing, while I'm thinking about it. "Eurynar" is a hell of a name for a lens, isn't it? Sounds like something you'd find in the men's room, in Japan.

No, Dave - Japan is an Asian country. Eurynars are found in France.