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30mm vs 1inch tube for light |
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Longshot
Optics GrassHopper Joined: May/06/2005 Status: Offline Points: 16 |
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Posted: May/13/2005 at 17:24 |
Some one settle the issue. I know the 30 mm tube allows for more windage and elevation adjustments than the 1 inch tube in most cases and is considered to be stronger structurally. But does the 30 mm tube actually transmitt more light than the 1 inch tube all else being equal?
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Chris Farris
TEAM SWFA - Admin swfa.com Joined: October/01/2003 Location: Texas Status: Offline Points: 8024 |
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Longshot
Optics GrassHopper Joined: May/06/2005 Status: Offline Points: 16 |
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Thanks for the links Chris. I haven't read all but the initial overveiw doesn't appear to give the 30 mm any sugnificant advantage in dim light conditons. This could save me a few few bucks.
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tbone1
Optics Apprentice Joined: May/31/2004 Status: Offline Points: 195 |
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Long shot, I have read all these posts and everyone has an opinion on it. In my opinion it really depends on whether you are talking about Euopean scopes or not. If you are talking about Leupold, Burris, Nikon, ect. I would agree that a 30mm is not any brighter than a 1", probably since the glass inside is the same size. But if you are talking about Zeiss, Swaro, Kahles ect. I personally think that there is a difference. The only way to really tell is to test them side by side in low light. For example a Swarovski PH 2.5-10x42 and a A-line 3.5-10x42, or a Zeiss VM/V 1.5-6x42 and VM/V 3-9x42 since they would have the same glass and coatings. No one has actually done this yet and I have'nt been able to either.
My Leupold 30mm is not any brighter than a 1" Leupold. However my Zeiss 30mm and S&B 30mm are noticably brighter than any other scope that I have. I realize that the glass is better, but I think personally think that it is partly due to the 30mm tube. I also think that a Swarovski PH 30mm is slightly brighter than the A-line series. I have'nt tested them side by side but I will soon. This is just my opinion though. |
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Jerod Johnson
Optics GrassHopper Joined: August/04/2005 Location: United States Status: Offline Points: 5 |
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30mm vs. 1 inch.,
The tube size does not reflect light transmission. It has to do with the erector system, that is where all of your light that gets bent and loses it's original colors gets managed back into true color. You are actually more likely to see(opinion) a little brighter/light transmission through a 1 inch tube vs. the 30mm. For instance, a 3.5-10x40mm PR and a 3.5-10x40mm LR/T. Same magnification but your chances of a little better brightnes are with the 1 inch(PR). The 30mms can have more lenses or a parallax adjustment that can slightly cut down on brightness or light transfer.
Any other differences in light transfer with the same magnification on scopes can be but not limited to: lens coatings filters reticles(a duplex reticle can appear brighter than a mildot or busy reticle because there is less in there covering up the area you are observing.
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Jerod
jjohnson@leupold.com |
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koshkin
MODERATOR Dark Lord of Optics Joined: June/15/2004 Location: United States Status: Offline Points: 13181 |
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All right, this has been addresses many times, and there are many
opinions. Most of the comparisons between 30mm and 1 inch scopes
are not apples to apples because of different coatings, polish, etc.
If we are talking about the difference between 30mm and 1 inch tube scopes and assume that optical quality is identical there is no difference whatsoever in light transmission. I may not have as much experience with different high end scopes as many other people here, but I do have a pretty decent idea of how an optical system works due to my background: I have a degree in applied physics specializing in optics from Caltech and I work with optoelectronic devices for Raytheon (lately, next generation night vision weaponsights and goggles). I've seen a lot of passionate arguments on this here and on other forums. People keep on referring to this as an opinion, but it really isn't. It is a cold, hard scientific fact: with the same objective size, same optical quality and same number of lens surfaces, in absense of vignetting (non-issue for rifle scopes), 30mm and 1 inch maintube scopes will have identical light transmission. I apologize if I ruffled anyone's feathers with this, but this issue needs to be put to rest. Ilya |
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Jerod Johnson
Optics GrassHopper Joined: August/04/2005 Location: United States Status: Offline Points: 5 |
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koshkin,
Isn't that pretty much what I said? I simply stated why some think that.
"The tube size does not reflect light transmission."
You sound a little upset about this. This is a forum and everyone can add some light. Don't get mad. I do not have your extensive backround, I am a HS grad with little college and a few years in the military. What I stated is basically how it all works. I agree with your statements, if this is not directed at me then my apologies.
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Jerod
jjohnson@leupold.com |
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cheaptrick
MODERATOR Joined: September/27/2004 Location: South Carolina Status: Offline Points: 20844 |
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Jerod and koshkin: Both of you nailed it, IMO.
Welcome aboard!! |
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If at first you don't secede...try..try again.
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koshkin
MODERATOR Dark Lord of Optics Joined: June/15/2004 Location: United States Status: Offline Points: 13181 |
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Jerod, I did not direct it at you (you were absolutely right in your earlier statement). It was more of a general rant. I keep on stumbling onto this 30mm vs 1 inch argument.
Usually, it restarts with some photographer who gets two PVC tubes of different diameter and measures the amount of light through each with his photometer. Then he/she makes a brilliant assumption that an empty PVC tube is an accurate representation of a lens system and here we go again.
Sometimes it gets even worse: some old timer who is convinced that nothing learned at school is ever useful calls me a snotty nosed kid (I am intentionally making the sentence civil) and assures me that according to his granddaddy (who incidentally slew the biggest blipping buck in three negihboring counties with nothing more than a flintlock and a flask of bourbon) pronounced on his death bed that 30mm is inherently brighter than 1 inch. I would never want to comment on their hunting skills since they have a wealth of experience in it, but, somehow, they think that looking at a bunch of scope ads is sufficient information to pronounce judgment with the gusto of a Supreme Justice.
Anyhow, I went off on a rant again. My apoligies. For some reason this argument ticks me off a little. I am normally a lot more level-headed.
Ilya Edited by koshkin |
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Jerod Johnson
Optics GrassHopper Joined: August/04/2005 Location: United States Status: Offline Points: 5 |
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IIya,
No worries, emails can be hard to "Read" sometimes. My fault.
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Jerod
jjohnson@leupold.com |
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Chris Farris
TEAM SWFA - Admin swfa.com Joined: October/01/2003 Location: Texas Status: Offline Points: 8024 |
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That's a classic!! You must be talking to same people that I do on the phone. |
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sandsock
Optics Apprentice Joined: January/16/2005 Location: United States Status: Offline Points: 172 |
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For me the decision one whether to buy a 30mm or 1 inch has more to do with why type of rings I already have than any phony concerns about "light transmission." In my experience I've seen better light transmission through high quality 1 inch scopes than lower quality 30mm (case in point is my Vari-X III compared to my Tasco Titan). You get what you pay for.
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cheaptrick
MODERATOR Joined: September/27/2004 Location: South Carolina Status: Offline Points: 20844 |
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Well stated, sandsock. I just seem to like a 30mm tube, I guess because most of my rings are 30mm. But, I have owned a couple great 1" tube scopes. (IE Zeiss Conquest.) |
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If at first you don't secede...try..try again.
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pooreyes
Optics GrassHopper Joined: October/08/2006 Location: United States Status: Offline Points: 27 |
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Thank you Koshkin and Jerod. I have been looking for this answer for a long time. I had to print this one out just to show the guys I hunt with, how there is no difference in the two as far as light. |
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Urimaginaryfrnd
MODERATOR Resident Redneck Joined: June/20/2005 Location: Iowa Status: Offline Points: 14964 |
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Where the difference comes in is when you want to make adjustments out to extreme long range. 30mm tubes allow more adjustment than the 1in tube. I also find that many of the 30mm tubes have side focus which I like. Probably my favorite scope is a 30mm Leupold VXIII 4.5-14x50 or it's Mk 4 twin.
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"Always do the right thing, just because it is the right thing to do". Bobby Paul Doherty Texas Ranger |
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Chris Farris
TEAM SWFA - Admin swfa.com Joined: October/01/2003 Location: Texas Status: Offline Points: 8024 |
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European 30mm scopes use larger internal componets and have the same amount of adjustment travel as a 1" tube scope. Only 30mm scopes with 1" internals will have more adjustment travel for long range shooting. This is the reason Schmidt & Bender had to go to a 34mm tube. |
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