Drinking Out Of A Fire House.
When drinking out of a gushing firehose, you can consume just so much. The rest spills out of your mouth and is wasted. The same principle applies when looking through an exit pupil: You can consume just so much. The rest “spills out” of your eye and is wasted.
The exit pupil of an optic is the column of light transmitted by the ocular lens, appearing as a circle of light visible in the center of the eyepiece when viewed from half an arm’s length away from your face. This exit pupil is measured in millimeters.
The formula to determine exit pupil of an optic is simple:
Objective lens diameter in millimeters divided by magnification
Example: With a 3.5-10x50 scope set at 10 power, divide the 50mm objective lens size by the magnification of 10; the answer is 5mm. Now, lower the magnification to 5x. Using the same formula, the exit pupil is now 10 (50mm objective lens divided by 5x = 10mm).
To continue the metaphor, If you can match the amount of water exiting from a firehose to the maximum amount you can drink, this is the most efficient, and nothing is wasted. You also don’t have to manhandle the impressive power that a fully charged firehose wields.
Likewise, if you can match the amount of light exiting a riflescope or binocular eyepiece to the maximum amount your eye can “swallow,” this is the most efficient, and nothing is wasted. You also don’t have to manhandle the extra weight, size and expense that an optic with a giant exit pupil might wield.
Young pupils dilate (open) a lot larger than older pupils. Various scientific studies reflect that an average maximum pupil size when dark-adjusted is about 7mm for people in their 20s to a maximum of 2mm for someone in their 80s.
Denne historien er fra August 2017-utgaven av Gun World.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent ? Logg på
Denne historien er fra August 2017-utgaven av Gun World.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent? Logg på
The First Rule of a Gunfight: Get a Gun
It is a time-honored tradition within the firearms industry; a decades-old trend hobbling on, despite evidence contrary to its practices: A woman entering a gun store, walking onto a range or participating in an event inevitably hears some variation of the words, “That’s an awfully big gun for such a little lady!”
Breaking Products And Deadlines
Confessions of a product test junkie
Guns Open Doors Of Opportunity
A Shooting Competition In Russia Emphasizes The Importance Of Freethinking And How It Opens The Door For Women Shooters.
The Ruger 10 Mil
Just as everyone is down-chambering 1911s to 9mm, the sr1911 goes 10mm ... For when follow-up shots aren’t an option.
S&W's Superb 6.5
SMITH & WESSON’S M&P10 RIFLE GETS THE PERFORMANCE CENTER TREATMENT AND EMERGES, CHAMBERED IN 6.5 CREEDMOOR, READY TO GO THE DISTANCE.
The Renaissance Rifle
THE HENRY BIG BOY ALL-WEATHER OFFERS UP TRUE VERSATILITY LIKE NO OTHER RIFLE.
Ammo Of A Higher Caliber
CHOOSING THE BEST CALIBER AND BULLET TYPE FOR DEFENSIVE AMMO CAN BE A CONFUSING PROSPECT.
Arsenal RPK - 3R
The Soviet/Combloc Light Machine Gun Comes To America—as A Civilian-legal Semiauto.
Single-Shot Hunter
Uberti has updated the old winchester 1885 high wall design into a modern carbine with old west flair.
Best Bullet
The .44-40 WCF Is a Leading Candidate for the Best All-around Cartridge of the Old West Era.