Home Forums Hunting & Shooting Hunting Optics 30 mm vs 1"

So 51mm objective in one-inch tube will provide more light to my eye than 50mm objective in 30mm or 34mm tube?

Hahaha, just when you thought that dumb cant get any dumber ...

[quote=ShakyHands]
, this is just pure physics.

Yes indeed, and you must have slept through the section in physics 101 that covered the focusing of light

ShakyHands, please explain to us your understanding of how an exit pupil is calculated.

OMG, what part of the exit pupil not being related to light transmission you don't understand?

Look dumbo, when you look through a scope at night you will see nothing regardless of your exit pupil size because there is no light coming through.

If tube diameter mattered to light transmission, why aren't all scopes straight tubes???

Just another know-it-all to put on Ignore. It’s not worth the effort to convince this type.

I have no idea why this is suddenly an argument, except argument has become a campfire
tradition and trademark...

I'm 65 now....and I've had a Cataract lens done on one eye...

Having used 1 inch tubes pretty much all of my life, I find myself having to squint
to see them, where in the past I hadn't....

So I've ended up with some 30 mm tubed scopes...

I don't have to squint to see thru those, especially at distance or on higher powers
like I have to do on the 1 inch scope tubes.. which include Leupold 3 x 9s.

and no, my eyes don't have a PhD in Optics, however they seem to have a preference
in what works for them now, vs in the past...

and as far as them being heavier, and popular in Europe... isn't most hunting in Europe
done at dusk and twilight, or under the full moon.. where hunters are stationary instead
of being pretty mobile like here stateside?

And that's a question, not a statement...

ShakyHands,

The problem with your "calculations" is the only occasions when the light passing through a 1" scope is at all constricted by the main tube is when the magnification's so low (below about 6x in a typical scope with a 40mm objective lens) the exit pupil is far larger than the human eye can use anyway.

I've proven this many times by actually measuring the exit pupil at various magnifications on many scopes. Above 6x, a typical 40mm-objective scope follows the same basic optical rule, regardless of whether it has a 30mm or 1" tube: Dividing the objective lens diameter by the magnification results in the exit pupil diameter. This means the light path is NOT restricted by the tube diameter, but by the internal optics.

Below 6x the exit pupil of the same scope may be constricted by the tube diameter, but is still far larger than the expanded pupil of the human eye.

--

This might be THE dumbest thing I have read in a while. But you know, I am aware of a few dozen hogs that only wish you were right. But you are NOT.

Here's a recent fly in your ointment, so to speak...taken around 9:30 p.m. with maybe 50 percent moon:

ohhh, boy............

If the QUALITY is identical, then ABSOLUTELY, a 30 mm tube will allow more light to transmit. For any of you keyboard cowboys that think otherwise, please study more, or ask your local Swarovski representative...

If your Swaro rep is telling you that, he needs to find another line of work. Absolutely false info.

The 30MM tube is a more robust handle......

You are right, exit pupil and light transmission are different things. But neither have anything to do with tube size. If you divide the front objective size by the scopes magnification the number you get is the diameter of the beam of light that exits the rear of the scope. A 40mm scope set on 4X = a 10mm beam of light regardless of whether or not the tube is 1" or 30mm. A beam of light 10mm in diameter is less than 1/2" and will easily fit through a 1" tube .

Each person is different, but most of us can only use 5-6 mm of light, any more is wasted. A 40mm scope set on 7x or 8X allows about 5 or 6mm of light to come through. If you want more magnification in low light you need a bigger front objective. But even going up to a 50mm objective will only benefit the user when the scope is set on 9X. At 10X it lets exactly the same amount of light through as a 40mm scope on 8X.. On magnifications less than 8x it does let more light through, but more than the human eye can use. If you are using a scope, or binoculars, with an exit pupil of 4 or less it can be much more difficult to position the eye to see through the scope. But once again, the tube size is irrelevant.

But none of this predicts how BRIGHT the light beam is. That is determined by the QUALITY of the scope lenses, not the size of the tube. The size of the beam of light and how bright it appears are 2 different things. Light transmission is much more difficult to measure and you see conflicting numbers. But as a general rule budget scopes let around 80-85% of the light that enters the scope exit the rear. Decent mid range scopes are in the low to mid 90% range and high end stuff in the 95%+ range. But once again the tube size is completely irrelevant.

It appears that ShakyHands is going to give Cummins Cowboy a run for his money in terms of optics knowledge. Just sayin....

Just when you thought that you have heard it, a guy will show up and will post a picture of a dead hog harvested under the moonlight to prove you that somehow an exit pupil size is related to the light transmission.

Maybe you can design a spotting scope with 95mm objective built on top of a one-inch tube that can be used in full darkness. It will be very light and very bright and you will have a best seller for sure.

Maybe they should redesign the Hubble Telescope because a one-inch tube provides as much light as big fat telescope ... LOL

I made NO mention of transmission or exit pupil. I simply responded to your ridiculous comment that you can't see ANYTHING through a scope at night. And by the way, I've used a 1" 3-9x40 Conquest with a #4 reticle to accomplish the very same feat. I also did so wiith 2 different Kahles. With an Elite 3200...with a Burris 3.5-10x50...should I go on???

I don't care what scope you have used because clearly, you just don't get it, when I wrote that "when you look through a scope at night you will see nothing regardless of your exit pupil size", clearly it was meant a complete darkness, not under the moonlight.

So yeah, for the stupid, there are some nights where there is some light available and there are nights when you don't see schit.

But regardless, an exit pupil is unrelated to the light transmission and that was my point so please stop twisting my words ... unless you want to prove something even more stupid than posting a picture of your dead hog.

it's a damn wonder anyone asks a question in the Optic forum. lol

http://www.nightforceoptics.com/news/see-light-light-transmission

shakeyhands hope you stick around for the comic relief.