30 mm vs. 1" scopes

[338Shooter]

This is SPARTA!

 

[ripnbst]

Go on...

 

[NikatKimber]

I'm with Dustin. Optics, like everything else in life, are a compromise.

If you want large FOV, high magnification, and high clarity... well, hello Hubble (and $$$$$$$$$$$$ price tag)

You want small size, large FOV; wave good bye to high magnification.

The length and diameter (at all parts along the length) of a scope play a part of the equation of FOV and magnification.

Large quality optics are expensive, and it's not a linear relationship. This is why you see high magnification scopes on .22s that are very long with small lenses (objective, ocular, and body diameters small), because they can maintain an acceptable quality on the smaller lenses. The sacrifice is in FOV at magnification.. and quality of construction.

Another point to consider, is that the scope has to mount somewhere. This means there has to be some "body" length to the scope. And since in many applications, the mounting system is limited to zero adjustment, this has to be more than a mounting *point*; in order for the individual user to get the focal point right for them.

I've got more, but it's time for church. Be back later.

 

[ronny]

You're goin' for help, right?

 

[MoBoost]

I'm with Dustin. Optics, like everything else in life, are a compromise.

If you want large FOV, high magnification, and high clarity... well, hello Hubble (and $$$$$$$$$$$$ price tag)

Sorry you can't have both - regardless of $$$$$$$$$.
Hubble's WFC3 aFOV is 2.7 arc-minutes - that's about 3" at 100yards; throw in 8000x magnification it is capable off and you get true FOV of 3/8 of a thousands of an inch - half as thick as human hair.

I agree - optics is always a compromise - with FOV it's the size of the eye-piece and the eye-relieve; it simply doesn't involve much else, unless you look into vintage scopes that had such a small objective that it became the "restriction".


P.S. Forgot to add ... THIS IS OSAAAAA!

 

[HMFIC]

Now that you girls have got yourselves all worked up over FOV, Steve's original question was about light gathering...

YES, all other things being equal, a 30mm tube does allow for more light transmission than a 1" tube. Period.

Now... do you need that? Who knows it's all up to what you think, but if you're hunting a lot in very low light or at night, you'll see improvement in the 30mm tube.

 

[HMFIC]

Oh... and just to get in the mix, Objective size does not determine FOV. Field of view is determined by the factors of magnification, focal length and lens geometry.

I can prove this to you on my stereoscope at home as well. The objective size never changes, but I can alter both the field of view and my working distance by using a range of barlow lenses and magnification changes.

 

[MoBoost]

YES, all other things being equal, a 30mm tube does allow for more light transmission than a 1" tube. Period.

Now... do you need that? Who knows it's all up to what you think, but if you're hunting a lot in very low light or at night, you'll see improvement in the 30mm tube.

Oh, common ... this IS going from bad to worse:

"The principal advantages of the 30mm tube are added strength and increased adjustment range for windage and elevation. For example, the M8-12X (1" maintube) has a total elevation adjustment of 51 minutes. The Mark-4 M1-10X (30mm maintube) has 90 minutes. The percentage of light passing through a scope is a function of lens coating and optical design, and has nothing to do with tube diameter."
Source - Leupold.

 

[MoBoost]

Oh... and just to get in the mix, Objective size does not determine FOV. Field of view is determined by the factors of magnification, focal length and lens geometry.

Correct. It doesn't determine FOV - but it can "choke" it like on very old low magnification scope like Wever 3-30: the tube was so long and magnification so small that the objective actually appeared in FOV.

 

[HiredHand]

I think this thread pretty much went to $h!t after me and Okmike chimed in.