The diameter of the objective lense determines the field of view visible through the scope; the larger the objective lens, the wider the field of view. Also, the larger the objective lense, the greater the resolution, brightness, and clearity.

The 50mm objective lense WILL gather more available light while providing a clearer image and give you a few minutes extra shootable light at the beginning and end of the day. I have a 40mm and a 50mm and there is a difference.

Your pick of the Leupold VXII 3-9x50mm is a great choice.

Happy Hunting!