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Kahles vs. older Simmons Aetec |
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jughead
Optics GrassHopper Joined: July/14/2008 Location: Huntsville, AL Status: Offline Points: 13 |
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Posted: July/23/2008 at 09:32 |
I knew that would get you guys' attention.
But, in all seriousness, that's the premise of this post. As I told you guys in my earlier post, I am a rookie when it comes to good optics as I've simply never had the income to even buy mid-range optics until now. To refresh you guys memories, I acquired a Kahles Helia 4x36 scope with a MZ I bought. Just for grins and giggles, I ran a test the other night to see just how superior this Kahles would be to the best scope I have personally owned which is an older Simmons Aetec (I think you guys call them Pre-Meade....whatever that means ). Since the Aetec is variable (2.8-10x44) I set it to 4x so it would at least be on the same magnification as the Kahles. Long story short, I went out every 5 minutes until total black darkness and was looking at a neighbor's birdbath in their yard (similar gray color to a deer) and though the crispness and clarity of the Kahles was in another league, I absolutely could tell NO difference whatsoever in the brightness category. In other words, I could have made a shot just as late with the Aetec as I could have the Kahles (I started looking through them every minute once it started getting really dark).
Is this normal? I really expected to see a huge difference, but didn't. Why? Does the 44mm objective make that big of a difference? I'm really at a loss because I've been really excited about getting some better optics for my rifles, primarily for woods hunting so perhaps I could make a shot on a big buck just a few minutes later. Obviously, this is a very limited test with no scientific validity whatsoever, but I still expected the results to be different based upon everything I've read. I'm interested in hearing anytying you guys want to throw out. Thanks!
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brodeur272
Optics Journeyman Joined: September/23/2007 Location: United States Status: Offline Points: 609 |
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Different eyes see different results. I know my Kahles Helia C 1.5-6 was great in low light last year. Have never been able to see that late with my Sightron SII. |
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jughead
Optics GrassHopper Joined: July/14/2008 Location: Huntsville, AL Status: Offline Points: 13 |
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Even so, I would love to hear opinions/theories from the guys on here who have so much more experience with optics than I do. |
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cyborg
Optics God Gaseous Clay Joined: August/24/2007 Location: North Georgia Status: Offline Points: 12288 |
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To answer your question The amount of exit pupil will determine the amount of light that will be transmitted to your eye. The Glass is going to determine the clarity and to a certain degree light. Both of these scopes have good coatings, the kahles has better glass. This being said is why you can see no appreciable difference in brightness. The true difference is can you see the finer things that will allow you to see that it is indeed a deer and not a stump, or tree. That is where the resolution comes in handy. Think about it this way you knew you were looking at a bird bath. To truly test this theory go somewhere that isn't familiar to you and look at several things with both. You will then see a big difference.
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With Freedom comes great responsibility, you cannot have one without the other
An armed public are citizens. A disarmed public are subjects. OATH KEEPER #8233 Support us, and join our cause. Cyborg |
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jughead
Optics GrassHopper Joined: July/14/2008 Location: Huntsville, AL Status: Offline Points: 13 |
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Anyone else who has input on this issue, please add it. Thanks! |
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cyborg
Optics God Gaseous Clay Joined: August/24/2007 Location: North Georgia Status: Offline Points: 12288 |
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I will say though the preMeade AETEC was a good little scope. One of my best hunting buddies has one. He got another a couple of years ago, that was not premeade, and he was so mad, he used it to hammer nails, and later decided it was a great target.
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With Freedom comes great responsibility, you cannot have one without the other
An armed public are citizens. A disarmed public are subjects. OATH KEEPER #8233 Support us, and join our cause. Cyborg |
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dougedwards
Optics Apprentice Joined: April/16/2008 Location: Williamsburg, v Status: Offline Points: 213 |
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I love Sightron II scopes when there is good lighting. Good contrast, great repeatable adjustments......but falls off hard in low light. Big Sky is a different story.
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but you brethren are not of the flesh but of the spirit if indeed the spirit of Christ dwells within you...Romans 8
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mercenary1947
Optics Master ** Joined: April/02/2006 Location: United States Status: Offline Points: 1392 |
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The only thing I can add is ... bird baths are tough to chew ..... I would'nt kill it if ya are'nt gonna eat it ! Plus have you ever seen that alfred hitchcock movie birds ? You're gonna have alot of p*ssed off birds after you !
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One Shot One Kill .... *S.O.F * Head Shots Only
SWFAM |
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tahqua
MODERATOR Have You Driven A Ford Lately? Joined: March/27/2006 Location: Michigan, USA Status: Offline Points: 9042 |
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Well said, Cyborg. In heavy cover at any distance in any light, the better glass will give you a shot. The lesser scopes will not. |
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silver
Optics Master Joined: November/04/2005 Location: United States Status: Offline Points: 2291 |
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Set a newspaper out at 75 yards and see which one will let you read more as it gets dark.
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"If we weren't all crazy we, We would go insane." Jimmie Buffet
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jughead
Optics GrassHopper Joined: July/14/2008 Location: Huntsville, AL Status: Offline Points: 13 |
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Ultimately, I'm just really hoping that the Zeiss Conquest 1.8-5.5x38 will absolutely satisfy me for what I'm looking for (I just don't WANT to spend anymore than that thing costs). Based upon Cyborg's post about exit pupils (more than twice the exit pupil at 1.8x compared to this Kahles I have) and Zeiss's website, this particular model should be pretty darn bright in the dark woods yet still scratch my itch for having low power settings for close range moving deer when the need arises. Best I can tell looking at the specs on the Kahles and Aetec, in all fairness, the exit pupil on the Aetec is substantially more on 4x than the Kahles is (if I interpolated correctly, about 12 mm vs. 9 mm).
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crispycritter
Optics Apprentice Joined: July/30/2004 Status: Offline Points: 115 |
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The guys have nailed it. A well lighted blob is still a blob. The better glass lets you identify the blob.
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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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Look at small details. That is the first step.
Then, look into the shadows: place an object there and see if you can penetrate the shadow and see the object. Then place a bright light within a few feet of the scope (in front of it), but outside of the field of view and see of you start getting odd reflections in there. Then look at the moon once it gets dark. Are there multiple ghost images formed? Then take a fairly bright light source and place it behind and to the side of the scope. Can you still see anything through the scope despite the light reflecting off of the ocular lens? On terminology: "brightness" as applied to what we see with a human eye is one of the most misleading and useless terms you could possibly use. Perceived brightness of the image depends on a number of parameters including resolution, contrast, light transmission, internal reflections, etc; with the total amount of light getting through being one of the less important ones. ILya |
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noluv
Optics GrassHopper Joined: July/24/2008 Location: uk Status: Offline Points: 13 |
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this is what i do lol but at the chip shop 300 yard away and i can clearly see it and read the adds in the window at 200+yard with a simmon wtc 6.5-20x50 and a old aetec phillipenes.
what they mean by pre meade mate is that meade has now took over and have up dated there models which in my opinion do not deserve the aetec name. looking threw my gun mart scopes section in detail there is not yes not 1 scope with simular magnification that can come close to the aetec on field of view. why cant these expensive makes make a scope like the aetec with massive field of view. did you notice the difference in field of view between the 2 scopes? |
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noluv
Optics GrassHopper Joined: July/24/2008 Location: uk Status: Offline Points: 13 |
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gun digest not gun mart i ment sorry
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Gunshow75
Optics Apprentice Joined: December/23/2004 Location: Kentucky, USA Status: Offline Points: 209 |
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You have been given very good advice, but I would like to respond to your "..I went out every 5 minutes until total black darkness ..." comment. This suggests that you did not allow your eyes to dark adapt, which will certainly comprimize what you were able to see in low light. Had you dark adapted and looked at small objects with a narrow color contrast, you might have been better served.
To address your question about the importance of the diameter of the objective lenses, lets use some simple concepts to help us: Light can be thought of as waves or particles. Let brightness be directly proportional to the number of light particles per unit area entering the scopes. Set the number to 100 particles per square millimeter entering the scopes. Assume that 90% of the light entering the objective lens exits the scope. The total light entering a scope will be equal to the total area of the objective lens times 100 particles per sq mm. The amount of light exiting the scope will be 90% of the amount entering the scope. The exit brightness is still directly proportional to the number of light particles per unit area exiting the scope. Your Kahles, with its 36 mm objective has a total input area of abouit 1018 sq mm, and the Simmons, with its 44 mm objective has an input area of about 1521 sq mm. The Kahles lets about 1018 * 100 = 101,800 units of light in, and the Simmons lets about 1521 * 100 = 152,100 units in. Since both transmit 90% of the available light,the light exiting is about 91,600 and 136,800 respectively. The diameter of the exit pupil for the Kahles would be 36/4 = 9 mm, and since you set the Simmons to 4x, it would be 44/4 = 11 mm. The area of the exit pupils are about 63.6 sq mm and 95 sq mm, respectively. So, the brightness of the exit pupil, what you see, for the Kahles will be about 91,600 divided by 63.6 = 1440. For the Simmons, it will be about 136,800 divided by 95 = 1440. The pupil in your eye will not be as large as even 9 mm, so you will have the same amount of light entering your eye from both scopes. If you had increased the power setting on your Simmons to about 7.3x, the exit pupil would have been 6 mm in diameter, about the diameter of your pupil. In that case, the light density would have been much higher and the Simmons should have seemed brighter. |
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Tom |
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Lurcher
Optics GrassHopper Joined: April/24/2006 Location: United Kingdom Status: Offline Points: 37 |
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I have had a S&B 6x42, Bushnell 4200 6-24x42. I still have IOR 16x42, Kahles Helia Super 3-9x42.
The best quality Optics for clarity are without doubt the Kahles.
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Sako .22lr S&B 6x42
Air Arms S410 .17 Bushnell 4200 6-24x40 FWB Sport 127 White Tail Classic 3.5-10x40 Essex UK |
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Gunshow75
Optics Apprentice Joined: December/23/2004 Location: Kentucky, USA Status: Offline Points: 209 |
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To continue with the discussion about objective lens diameter using the same criteria, lets look at some potential variable scopes with different objective diameters, all set to 4X:
power,dia Set Power Exit Pupil Exit Density A 1.5x6,42 4.0 10.5 1440 B 2x7,36 4.0 9.0 1440 C 2x8,42 4.0 10.5 1440 D 3x9,40 4.0 10.0 1440 E 3.5x10,44 4.0 11.0 1440 F 2.5x10,50 4.0 12.5 1440 G 3x12,56 4.0 14.0 1440 H 3x12,40 4.0 10.0 1440 At 4x, all will have the same brightness value. Now, lets change the power setting such that we get a 7 mm exit pupil. When we arrange them from lowest to highest output light density value: B 2X7,36 5.1 7.0 2380 D 3X9,40 5.7 7.0 2939 H 3x12,40 5.7 7.0 2939 C 2x8,42 6.0 7.0 3240 A 1.5x6,42 6.0 7.0 3240 E 3.5x10,44 6.3 7.0 3556 F 2.5x10,50 7.1 7.0 4592 G 3x12,56 8.0 7.0 5760 All other things being equal, as the exit pupil is made smaller to approach the diameter of your eye's pupil in low light, the light density increases as the size of the objective diameter increases. So, after spending a lot of time on simple arithmetic, we can see that bigger objective lenses are capable of providing a brighter image, if, and only if, everything else is done correctly. And therein lies the problem with inexpensive scopes. |
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Tom |
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sakomato
Optics Master Joined: February/28/2008 Location: Houston Status: Offline Points: 1166 |
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Excellent post Gunshow75!
Where I think the comparison might be tweaked a bit is
"Assume that 90% of the light entering the objective lens exits the scope. "
as I think the Kahles may lose less light through the superiority of its coatings and glass. Probably not a huge difference though.
Also I'm trying to wrap my mind around the "light density" statement. Sorta like HD TV? More pixels per sq inch? Could you expain that a little further?
I have an older Simmons Aetec 3.8x12x44 also and it is my scope that I switch around if I want to put a temporary scope on to work up loads while waiting on another or if I want to check against another scope to see if the scope was the problem. IMO, they were very good scopes, especially for the money.
noluv, I'm with you on the field of view. The larger the better when it comes to running shots or finding game in a monochromatic background situation. Used to love the old Aetec 2.8x10x44's with about 34' FOV at the lower power. My first expensive scope was bought for the specific reason of a 34.5' FOV and that was the Zeiss Diavari 2.5x10x50.
The older Aetecs were tough also. On a West Texas mule deer trip I was making time down a dirt road to go around behind some deer spotted a mile away and had my gun come out of my 4 wheeler gun boot and slide down the road in the dust at about 30 mph. Needless to say I hunted with my other gun the rest of the trip, but when I got back to town afterwards that scope was still zeroed.
I might just look around the auction sites and pick up another pre-meade for a new AR barrel I've got coming.
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Guns only have 2 enemies, rust and politicians
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Gunshow75
Optics Apprentice Joined: December/23/2004 Location: Kentucky, USA Status: Offline Points: 209 |
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My explanation was designed to address objective lens size, and only that. As such, I could use 50% transmission or 100% transmission and we would get the same relative results.
Superior coating are crucial in light transmission. I think top line manufacturers like Zeiss, Kahles, S&B, and so on have transmission values of about 90 to 95%. I don't think the glass itself attenuates much light. As regards 'light density,' just think of it as the amount of light per unit area. Think of your pixel as a small square. If ten units of light per second enter each pixel, and it takes 100 pixels to cover your pupil, then 10 x 100 = 1,000 units of light per second will be going into your eye. I don't know anything about Simmons scopes, so I don't have an opinion about them. I will say, however, that any inexpensive scope will have shortcoming. The ones I have seen usually have poor resolution and poor color contrast properties. I have compared both Zeiss and Kahles to a lot of Bushnell and Leupold scopes while deer hunting in Canada. In low light, low contrast situations, Zeiss and Kahles have always been superior. |
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Tom |
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