What You May Not Need in Your Hunting Scope
What you probably don’t need in a general purpose hunting scope are an oversized main tube or a huge objective lens. A larger main tube does not increase brightness, but does provide more room for turret adjustments. If you’re not dialing for extreme-range shots, a 1-inch main tube will keep your rig smaller and lighter. Those 50mm to 56mm objectives do admit more light into the scope, but you might not need it. High-quality, fully multi-coated scopes transmit 90% or more of the light that enters them these days, and at 8X even a 40mm objective produces a 5mm Exit Pupil. That’s more than enough light to clearly see a black reticle against the hide of a mule deer, elk, and even a black bear a good half-hour after sunset, if not a full hour later. Shooting hours in many states end a half-hour after sunset anyway. Objective lens diameter divided by magnification produces the exit pupil in the eyepiece. If this equals or exceeds the dilation of your own pupil, you’re taking in all the light you can. The human pupil opens to more than 5mm well after sunset, so you can’t take advantage of an exit pupil that large or larger for more than perhaps an hour a day. After age 50 or so many pupils lose their ability to open more than 5mm, so a 6mm to 7mm exit pupil is wasted. Why put up with the oversized objective? You can always increase exit pupil size (thus image brightness) by dialing power down. A 50mm objective at 10X = 5mm EP. A 50mm objective at 8X = 6.25mm EP. Dial down to 6X and exit pupil widens to 8.3mm!
Ballistic Reticles or Turrets?
Choose turret dialing or ballistic reticles if you like, but neither is necessary for shots inside 300 yards or so with most modern, bottlenecked cartridges. Unless you are extremely fast and competent operating an elaborate scope, you might be better off with a simple duplex reticle and a Point-Blank-Range sighting system (read all about that in this RSO post.) This will suffice for well over 90 percent of your shots.
Source
How To Choose Your Best Hunting Scope — Ron Spomer Outdoors is written by Ron Spomer for www.ronspomeroutdoors.com