in a 4 x 28, the "4" stands for 4 times the magnification, the "28" is the size of the objective lens in millimeters.
in a 3 x 9 x32 scope, it denotes a scope that has a bottom end magnification of 3, variable to a top end magnificaion of 9, with a 32mm objective lens.
All of this is subjective as the magnification power settings are "rounded" to the nearest whole number. Many that say "3" power may be closer to a 2.8 power or a 3.1 power in strength.
As far as the objective end, generally, the larger the objective end, the more light gathering capability the scope has in gathering light in low light situtations to see the image. From memory, it has to do with the size of the exit pupil of the eye. An old rule of thumb was to take the objective end of the scope and devide by "7" . This would show the maximum power setting on a scope that would allow the most light for the image to be transmitted to the eye. Again, from memory 7 mm is the maximun exit size of the eye pupil for gathering light. The 4x28 scope would then transmit just as bright and clear of an image as a 4x32 or a 4x36 scope. But a 4x20 scope would not present a clear bright picture in low light conditions as twenty divided by seven would indicate its brightest power setting would be a little less than 3x power. You would probably not notice this until late evening or early morning as it would not make a hoot of difference at 1pm in the afternoon. AGAIN THIS IS FROM MEMORY SO SOME OF IT MAY BE SUSPECT. Then the quality of the lens and various coatings set in to effect light transmission and clarity as well but i can't remember all that techinical stuff and terms.
The down side is the bigger the objective lens is for more magnification/light transmission, the bulkier the scope and higher rings may be required to get the objective end off the barrel.
the other main thing i consider is i want a scope with a one inch diameter tube as there are tons of rings available fo that size scope tube body. All ruger 77 rifles leave the factory with 1" scope rings and 1" is the most popular size by far in this Country...........
here is a link to chuck hawks information site. This may help.......
http://www.chuckhawks.com/index2i.scopes_optics.htm
in a 3 x 9 x32 scope, it denotes a scope that has a bottom end magnification of 3, variable to a top end magnificaion of 9, with a 32mm objective lens.
All of this is subjective as the magnification power settings are "rounded" to the nearest whole number. Many that say "3" power may be closer to a 2.8 power or a 3.1 power in strength.
As far as the objective end, generally, the larger the objective end, the more light gathering capability the scope has in gathering light in low light situtations to see the image. From memory, it has to do with the size of the exit pupil of the eye. An old rule of thumb was to take the objective end of the scope and devide by "7" . This would show the maximum power setting on a scope that would allow the most light for the image to be transmitted to the eye. Again, from memory 7 mm is the maximun exit size of the eye pupil for gathering light. The 4x28 scope would then transmit just as bright and clear of an image as a 4x32 or a 4x36 scope. But a 4x20 scope would not present a clear bright picture in low light conditions as twenty divided by seven would indicate its brightest power setting would be a little less than 3x power. You would probably not notice this until late evening or early morning as it would not make a hoot of difference at 1pm in the afternoon. AGAIN THIS IS FROM MEMORY SO SOME OF IT MAY BE SUSPECT. Then the quality of the lens and various coatings set in to effect light transmission and clarity as well but i can't remember all that techinical stuff and terms.
The down side is the bigger the objective lens is for more magnification/light transmission, the bulkier the scope and higher rings may be required to get the objective end off the barrel.
the other main thing i consider is i want a scope with a one inch diameter tube as there are tons of rings available fo that size scope tube body. All ruger 77 rifles leave the factory with 1" scope rings and 1" is the most popular size by far in this Country...........
here is a link to chuck hawks information site. This may help.......
http://www.chuckhawks.com/index2i.scopes_optics.htm