10x36 vs. 10x42

[caleb0100]

Hey all,
 I just found what I think is a good deal on some nikon monarchs, but they are 10x36 and I was hoping for 42's. How much of a difference is there, and will I even notice it? I mainly only hunt whitetails here in sw pa. but we will be making a trip out to colorado this fall for elk. What do you guys think?

[Montanawidower]

I like my 10X42s steiners for western hunts but for whitetails... I don't think it matters.  I usually use 8X's on stand (whitetails) because they are much smaller.  My two cents.

[LKH]

Unless you are going to be hunting open country out west and plan more trips, you would probably be better off with 8 power.  

The 42 will definitely give you better results in poor light conditions, often the case with elk.

[cyred4d]

For treestand hunting I prefer the 8x binos. Out west you would appreciate the 42's though.

[Tree Rat]

Exit pupil is always a consideration in glass (binocs, scopes etc) The human pupil maxes out at about 5mm. That means in pitch black your pupil opens to 5mm the maximum amount of light it will allow into the eye.

Exit pupil is the diameter of the light transmitted through the scope to your eye.

It is calculated by dividing the objective lens by the magnification. 10x36 has an exit pupil of 3.6mm, 10x42; 4.2. That means the 10x42 is much better in low light.  

An 8x42 would be even better at 5.25. Anything higher than that becomes wasted overkill as your eye can't receive it.

There are may other things to look at, but that is the primary "light gathering" factor to consider. (scopes can't actually "gather" light, but that's another story)

[Mike Vines]

Originally posted by Tree Rat:
Exit pupil is always a consideration in glass (binocs, scopes etc) The human pupil maxes out at about 5mm. That means in pitch black your pupil opens to 5mm the maximum amount of light it will allow into the eye.

Exit pupil is the diameter of the light transmitted through the scope to your eye.

It is calculated by dividing the objective lens by the magnification. 10x36 has an exit pupil of 3.6mm, 10x42; 4.2. That means the 10x42 is much better in low light.  

An 8x42 would be even better at 5.25. Anything higher than that becomes wasted overkill as your eye can't receive it.

There are may other things to look at, but that is the primary "light gathering" factor to consider. (scopes can't actually "gather" light, but that's another story)

That's what I like about knowing you Terry.  I pick the knowledgeable ones to be around me in hopes that it will rub off on me.  It just never seems to go that way, but thanks for hanging around me anyways.

[Bjorn]

My fav for spot and stalk is 6x30; enough magnification, lots of clarity and good field. 8x40  is good too, for me 10x is great for glassing where you can get them steady and survey a big area that is fairly far away.

[Steve O]

Couple other things...

The amount of light passed thru the binocs depends on the # of lenses and the type of coatings on those lenses.

YOUNG human pupils open to around 5mm.  The older you get, the less they open wide.    :D

Look up "twilight factor" it is more important than exit pupil.

Optics are a prime example of "you get what you pay for".  Anybody who says a $200 of binos will do the same as an equal size $1000 pair has never used the more expensive glass.

Odds are you are not going to be able to tell any difference at all between those 36mm vs 42mm.  What is that?  Less than 1/4" on the diameter.

[KEG]

I agree with Tree Rat except from what I have read the maximum the pupil can open is about 7mm not 5mm. This is why binos go up to 7X49, 8x56 etc.

[Tree Rat]

Geeze pick on the guy with "old timers"    :p   It's been a long time since I researched scopes.
Probably long enough that my eyes open to 4.2mm   :eek:   Newfangled twilight factor terms and such. (I do vaguely remember that...)

If memory serves Eagle Optics has good educational info on their site.

found a good Q&A here -- birdwatching dot com optic myths (in case the link gets yanked)
 
 http://www.birdwatching.com/optics/myths2006-9.html

[NoCams]

I am thinking of biting the bullet and buying a pair of Swaros in 8 X 32 instead of the usual 10 X 42's Leupold pinnacles. Loved my Pinnacles but they were a little big and heavy. I was able to see deer after it was too dark to shoot with them. I am thinking the Swaros will give me a good image and also be able to see after shooting light all in a smaller lighter package ? I have heard that premium glass in a lower power and smaller objective diameter  than say $200-400 glass of higher power and objective diameter will give you the same or better image and twilight factor ? What say ye tradgangers ?

[Steve O]

Jimmy,

You cannot go wrong with any of the Swarovskis.  I had 8x30s over 20 years ago that I could see in the dark with.  They have only improved since then.

[Shawn Leonard]

I like 8 power for the hunting I do, I have some Nikons in 8 by 36 that I love. 10 power can be a bit tough to get a good steady view in heavy cover. 42's are just to big for me to carry as well. Shawn

[amar911]

You will get 1.36 times as much light through the same set of 10x42 binos as you will through the 10x36 binos. That is definitely significant in low light conditions. If you want a smaller objective lens (which I generally do for most of my hunting), then go with a good 8x30 like the Swarovskis that Steve mentions, or the even better Leica 8x32 HD binos. The problem is cost! Those Leicas cost $1900 at the optics discount houses and the 8x30 SLC Swarovskis are relatively cheap at a still expensive $900. I have both, plus quite a few other premium binoculars of various sizes from 7x24 to 15x56, and I can say that unless you MUST HAVE the absolute best, the Swarovskis are the way to go in a premium binocular and the 8x30 is just about the perfect all around size. I have used my 8x30 SLC Swarovskis for the last 15 years for the majority of my hunts, and they do everything well. The Leicas are fairly comparable, but a little better, and they are smaller in overall size, making them superior in every respect -- EXCEPT PRICE. There are other good binos on the market for less money that the Swarovskis, but for significantly less money you will be buying significantly less quality, as Steve also said. Buy the best you can afford, and you will never regret it, especially when you get to the level of the Swarovskis. Remember, when you are hunting you will be looking through your binoculars far, far more than you will be shooting your bow. Also, if you book outfitted hunts, you will be spending quite a bit of money just to have the opportunity to see and shoot animals. Upgrading to high quality binoculars that you can look through for hours a day and clearly see animals and other objects is more important than upgrading just about any other equipment you will take on a hunt as far as making a real difference in your hunting success. A $900 price tag is big, but no bigger than what many of us spend on yet another custom bow that won't kill an animal any deader. Don't think I am discouraging anyone who already owns nice binoculars from spending money on custom bows.      

Allan