Naahhhhh, they weren't ON me. Just checkin' for ticks with a magnifying glass and one thang led to another........
Naahhhhh, they weren't ON me. Just checkin' for ticks with a magnifying glass and one thang led to another........
T
Top
Guest
Thank You
Thanks for your replies! Yes the Kowa was clearer but all n' all the Leupold, taking into account its disadvantages wasn't all that bad or perhaps a better way to put it, pretty good considering the conditions.
Tom
Thanks for your replies! Yes the Kowa was clearer but all n' all the Leupold, taking into account its disadvantages wasn't all that bad or perhaps a better way to put it, pretty good considering the conditions.
Tom
Bill Wynne
Active member
Isn't the objective lens round?
The formula for the area of a circle is Pi x the radius squared. I believe that some of you were using the square of the diameter.
The area of a 60mm lens is (30 x 30) x 3.14 = 2826 square mm. The area of a 45mm lens is 1590 square mm.
Therefore: a 45 mm lens gathers 56% of a 60 mm lens.
I do not intend to offend but correct.
Concho Bill
The formula for the area of a circle is Pi x the radius squared. I believe that some of you were using the square of the diameter.
The area of a 60mm lens is (30 x 30) x 3.14 = 2826 square mm. The area of a 45mm lens is 1590 square mm.
Therefore: a 45 mm lens gathers 56% of a 60 mm lens.
I do not intend to offend but correct.
Concho Bill
Yes
light gathering power varies with the square of the radius, so going up in lens diameter/light gathering ability is not a linear thing. A little bit pays a much bigger dividend.
light gathering power varies with the square of the radius, so going up in lens diameter/light gathering ability is not a linear thing. A little bit pays a much bigger dividend.
DeltaBravo
Member
Bill,
Using the diameter works the same way. The area of a circle is pi times radius squared, that's true, but the diameter is radius times two, so 2R squared over 4 is the same thing. Either way, it works out the same. The 60 mm scope gathers 1.77 times a much as the 45; or the 45 gathers only 56% of the light that the 60 does. Six of one, half dozen of the other.
Now, what was the original question???
Dennis
Using the diameter works the same way. The area of a circle is pi times radius squared, that's true, but the diameter is radius times two, so 2R squared over 4 is the same thing. Either way, it works out the same. The 60 mm scope gathers 1.77 times a much as the 45; or the 45 gathers only 56% of the light that the 60 does. Six of one, half dozen of the other.
Now, what was the original question???
Dennis
Bill Wynne
Active member
Bill,
Using the diameter works the same way. The area of a circle is pi times radius squared, that's true, but the diameter is radius times two, so 2R squared over 4 is the same thing. Either way, it works out the same. The 60 mm scope gathers 1.77 times a much as the 45; or the 45 gathers only 56% of the light that the 60 does. Six of one, half dozen of the other.
Now, what was the original question???
Dennis
That's right, Dennis! I checked it out.
...and the same works for a square lens except you don't have to mess with the pie.
Concho Bill
Sometimes your brevity is just plain EVIL
David
It would take either a surgeon's steady hand or one tough sum bi-ch to burn one off your own body. They only latch on to the most tender parts you know.
My child bride keeps telling me not to post! I should listen.