Home Forums Hunting & Shooting Hunting Optics Interesting read on 40 MM and 50MM scopes by Chuck Hawks

I have no idea how much weight to give an answer to this question on this thread, but here goes.

1) Does a 50mm objective give a brighter image than a 40mm objective when the power of each results in the same size exit pupil?

2) Is it easier to make an exceptional 50mm objective lens as opposed to making an exceptional 40mm one?

I will sorta answer the above question. Although the answer will be two binoculars and not two scopes. But at leased you will get something to rebut or agree with.

Sunset is at 4:47 today. I went back out and laid them on the sandbags at 4:40. With the Nikons 7X35 I could barely make out the fork of the antlers on the fence 131 yards away. At 4:44, if I didn't know they were antlers, I could not at make them out. Back and forth every minute between them and the Bushnells 8X40 proved again what I have stated many times here: "Larger exit pupil helps in low light" is an internet optical myth. The Bushnell allowed me to see the fork until 4:54. That�s an extra fourteen minutes. Finally at 4:59 I could not tell the antlers were there. For those who don�t know exit pupil is the objective diameter divided by the magnification power. Both have an exit pupil of 5mm.

The size of the exit pupil determines the amount of light available to the ocular lens regardless of power. Back in the day, it was easier (cheaper) to make quality lenses that were smaller. However, with today's manufacturing methods high quality larger lenses are easy to make.

& raise you one

I'm confused about something written here. Somebody wrote that they used a higher power scope to identify a target was a doe not a buck.

Do people really point a scoped rifle at unknowns to identify a target? Would you use a hammer when you need a wrench? I'm stumped that this would still happen! How could anyone point a rifle loaded or not at an unknown target?

This is what field glasses are for. You identify your target before you point a high powered rifle at it. It's not just simple courtesy towards other people and property, but basic common sense and gun safety.

Some do. Where I used to work at the door plant I had a boss who told me that's what scopes are made for. He used his rifle scope to glass for game. I never hunted with him.



I bet at least half the folks who post on 24hour do it. When I was young I used to and bet most have.



Millwrights do the opposite all the time. If they could they would.



If you go back into your history you will see you posted that you told one of your clients to turn up his scope so he could see the animal in low light. I have used your experience as additional proof that turning up the magnification on your scope allows one to go longer into low light.

You are the same as the guy above who pointed a scoped rifle at a KNOWN target, a deer, to verify whether it was a buck or doe. The hunter found the deer with 8X binos; to use your term "field glasses". In the light available he could not tell if it was legal with his 3-9X scope. I had to turn up my scope all the way to 25X to verify whether the hunter was going to shoot or not. I do NOT apologize for pointing a loaded or unloaded rifle at a game animal I or someone with me might shoot if it is legal. The scope is the last chance to verify a legal kill.

I have to say I agree with Ringman. The target is identified, it's a deer, you're not compromising safety at all by putting it in the scope to decide if it's a shooter or not. If you're glassing or checking out movement with your scope then that's a different story, but there's nothing unsafe about looking at something you already know to be a deer through your scope for a final evaluation.

In the south where I hunt if you see a deer and can tell it's got a decent rack on it then you'd better be looking through your scope at it pretty quick or you won't get another chance. I've had good bucks get past me because I screwed up and tried to evaluate them through my binoculars instead of my scope. Our deer don't typically stand around in open fields in the daylight waiting for you to look them over and decide if you want to get your gun up.