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Posted: 8/23/2011 8:32:22 PM EDT
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For scopes that do not not have daylight visible illumination, or scopes where the illumination washes out in bright light, does the addition of an ARD allow the illumination to be seen in daylight?
I realize ARDs suppress reflections from the objective end of the scope, but are there any additional benefits when looking through them? Reason I ask is I was checking out a mini ACOG in a local gun shop today, and the green tritium illumination showed up fine when aiming at indoor objects in normal, daytime- indoor lighting, but when looking out through windows into the bright Colorado sky and tree limbs/leaves 75-100 yards away, I couldn't pick out the tritium easily. You could see the reticule OK, but it was indistinct, plain black, no color whatsoever. I wasn't thinking about adding an ARD when the salesman was demoing it for me, but now I'm getting to wondering...... Would a Sun Guard (tanebraex sp???) do the same thing or does it operate differently? |
| No an ARD won't help in that situation. The problem you ran into is a reasonably well-known issue with ACOGs, and happened because the fiber optic was only picking up the dim interior light but the target was lit by much brighter daylight. The Browe Combat Optic, by a former Trijicon guy, claims to solve this problem using a battery-powered reticle and some electronics. Cleverly, it appears that they're using a center-weighted camera exposure meter to adjust the reticle brightness, so the reticle is always a constant brightness relative to the target, not relative to the shooter as with ACOG. Possibly because the doesn't have to make the reticle any brighter than necessary, they're claiming pretty decent battery life, 2000hrs avg, 750hrs on max brightness. They've got a motion sensor that will turn the scope off after awhile, and will automatically turn it back on when you pick up the rifle. Pretty clever scope, all in all. |
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It has nothing to do with the tritium, as stated above it is the amount of light the fiber optic element is picking up where you were standing. If you had stepped outside it would have lit the recticule a lot brighter. Also the red is easier to pick up on a bright background IMHO, you may want to give the red a try. Posted Via AR15.Com Mobile |
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Quoted:
It has nothing to do with the tritium, as stated above it is the amount of light the fiber optic element is picking up where you were standing. If you had stepped outside it would have lit the recticule a lot brighter. Also the red is easier to pick up on a bright background IMHO, you may want to give the red a try. Posted Via AR15.Com Mobile Disregarding the impact on the tritium, would the idea of reducing lighting coming in the front of the optic by the 15% claimed by the ARD folks help balance the level of reticule illumination provided by the fiber optic element with the available light? I realize that available light can/does overpower the illumination provided by ambient light through the FO element, but I'm hypothesizing that if we could reduce the amount of light travelling through the lenses, the ratio/balance between FO illumination and light transmission through the scope could be restored to a more favorable balance. Any credence to that hypothesis? |
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Quoted:
Disregarding the impact on the tritium, would the idea of reducing lighting coming in the front of the optic by the 15% claimed by the ARD folks help balance the level of reticule illumination provided by the fiber optic element with the available light? The difference between brightness indoors and brightness outdoors is way more than 15%. The camera guys have a useful concept called Exposure Value, where each EV has twice as much light as the one below. So a scene at EV6 has twice as much light as one at EV5. Indoors is usually somewhere around EV5. Outdoors in a sunny sky is somewhere in the range of EV12 (overcast day or shade) to EV16 (sunny cloudless day in sand or snow). So from indoors to overcast sky is 2 (EV5->6) x 2 (EV6->7) x 2 (EV7->8) x 2 (EV8->9) x 2 (EV9->10) x 2 (EV10->11) x 2 (EV11->12) = 128 - meaning that a cloudy day is roughly 128x brighter than indoors. If you're indoors looking at a target in full daylight then you have to go from EV12->15, so double that three more times (128 x 2 x 2 x 2 = 1024x brighter). An ARD may shave off 15%, but that's nothing, that means it's only 110x - 850x brighter... |
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