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Ken

As has been mentioned the small objective on a low power scope already lets all the light through the eye can use, especially in day time when your pupil is smaller.

The field of view is not determined by the size of the objective.

So in short, from an "optics" point of view of scope used in the day time there is no gain having the bigger objective on a low powered scope.

If you divide the objective size (in mm) by the power the answer you get is the size of the exit pupil and 7mm is the max the eye can use and that is the max your pupil will dilate if you were in the dark. This is why for night use you have the various European scopes that are 8 power and 56 mm objective, the various 8 X 56s.

If you look through a scope and move your head back the "hole" you are looking through will get smaller as you move your head further back until you finally reach a point where the hole does not get any smaller. The small hole you are looking through is now equal to the exil pupil diameter. Thus if you had an 8 X 56 and 8 X 28 scope the hole you would be looking through on the 8 X 56 would be twice the diameter of an 8 X 28 scope. But a 4 X 28 would have the same size hole as a 8 X 56. If you were shooting at night time such as spotlight shooting the image with a 4 X 28 and 8 X 56 would be of equal brightness but of course the image with the 8 X 56 would be twice as big.

Mike

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