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Thread: True Red-Arc AAA vs CMG Infinity as cockpit light

  1. #1
    Enlightened
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    Default True Red-Arc AAA vs CMG Infinity as cockpit light

    Between the CMG Infinity and the Arc AAA (or others of similar size), which small LED light has the deeper/truer red (longest wavelength)?

    For my needs, brightness is not a factor. It will be used as a "cockpit light" in a car for doing paperwork while maintaining night vision somewhat. Thus, preference is given to a dimmer true red over a bright orange-red.

  2. #2

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    I think the CMG should be fine for that. I wouldn't describe it as orange-red, it's the same color as most other red LED's. I think some exist that are a deeper ("cherry") red but those are unusual.

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    Flashaholic dasfx's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    I have 3 red CMGs (gen 1 with no texture on the head) that I use all the time (nothing as cool as a cockpit, but, a boy's gotta pee right?). I've also used it for nighttime walks and meteor showers. The light is nice and wide, great for an area light at night.

    DasFX

  4. #4
    *Retired* The_LED_Museum's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    I also have an original style red Infinity, with no texture on the head. I don't know where it is at the moment, but as I remember, it uses a true red (640-660nm) LED, and has a remarkably smooth beam considering the LED type.



    Note: This picture was taken in early 2000 with a Jam Cam, before I got a good camera.
    This red Infinity was the very first flashlight I reviewed. There are 415 .htm files in my d:\gomer\led\ subdirectory, and I'm guessing that at least 350 of them are flashlights. [img]/ubbthreads/images/graemlins/eek.gif[/img]
    I don't know where the red Infinity is now, but I'm sure it's around here *somewhere*.

  5. #5
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    Kiessling's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    or buy yourself some deep red single LEDs and put them in a Photon Microlight ... and you get the deepest red you'd ever want.
    This is very easy, even a technical dumbass like me can do it.
    bernhard

  6. #6
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Before you pick a red led, take a look at this site - http://stlplaces.com/night_vision.html - it makes interesting reading!

  7. #7
    Flashaholic* Quickbeam's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Aux,

    We have a good friend who lives a short distance from me who is a pilot - for a living, not just pleasure. He loves the Infinity Red and still has it despite the fact that it has been mostly usurped by the Red LED A2 we just gave him as a late birthday/early christmas present (he went NUTS).

    The red Infinity produced just enough light for reading instruments and maps and he would use it by placing it over the ear of his headset under the headstrap so it would shine wherever he was looking.

    Off topic:

    Re: that article debunking Red light as the proper light to use for night vision. IMHO, although it has some good information, it may be misinterpting some basic facts about vision. My conclusions, based upon published research papers about vision available at any university library (in all likelihood more relable than "internet sources"). I really wish I had kept my college research papers so I could give exact references, but I remember their content and here is what I came up with:

    1) The parts of your eye responsible for night vision essentially blind to red light, so red light preserves night vision because the rods are essentially unaffected.

    2) The fovea of the eye, where you see the most detail, has the least rods. Red light stimulates the cones in the fovea allowing you to see good detail while not burning out the rhodopsin in the rods.

    3) Green and blue green light bleaches the rhodopsin in the rods, making them less sensitive to dim light (a fact frequently overlooked), while red does not.

    4) Intense red light will produce afterimages that can overlap with night vision perceptual fields, so keep the red light as dim as possible.

    5) For most users, a very dim white light will work nearly as well as a dim red light, since the levels at which preserving night vision are critical (astronomy - perception of extremely dim stars) are rarely needed by the average user.

    So basically there is no need to bother with green or blue-green light at all unless you want to show off your neat new LED light to your friends and get a "wow" out of them... [img]/ubbthreads/images/graemlins/rolleyes.gif[/img] ...or you are using night vision equipment, which is a whole different story.

  8. #8
    *Retired* The_LED_Museum's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Red light can render red lines and other red articles on maps essentially invisible, so that needs to be taken into account too. If there are no red lines or other red features in your map, no problem then.

  9. #9

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Besides making red lines disappear, a red led (or any other monochromatic led) will make all colors on the map look the same. If the map uses different colors to convey information, a white light really helps. Other than for map reading, white leds on keychain lights etc. are in my experience not all that important and I've done fine with a green Photon II.

  10. #10
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    So far, nobody has recommended the red Arc AAA. Is it perhaps too bright for my described use?

    I have no issues with the recommended Infinity - it is less expensive after all!


  11. #11

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Aux, the main prob with the red Arc AAA is they don't make it any more. You might be able to find a used one on BST.

  12. #12
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Yes, assuming I can find some.

    The Arc AAA is smaller, but I am wondering if it would be too bright for closeup work.

  13. #13
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Pocketlights has ARC AAA Red, here
    http://www.pocketlights.com/arcaaan.asp

  14. #14

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Aux, I think smallness matters mostly if you're going to EDC the light. If you're going to leave it in your car, the Infinity is plenty small.

    My guess (unconfirmed) is that the Infinity and Arc leds are the same color. I don't know which is brighter, but they are both red, probably around 650nm. There's nothing "false" about that red, it's really red, it's just not as deep a red as the 690nm(?) cherry red color most commonly seen in cheap keychain lasers.

  15. #15
    *Retired* The_LED_Museum's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    [ QUOTE ]
    paulr said:
    ...it's just not as deep a red as the 690nm(?) cherry red color most commonly seen in cheap keychain lasers.

    [/ QUOTE ]
    Just FYI, the red laser diode found in most of those really cheap laser pointers is 650nm, and I'm guessing they can vary between 650nm and 660nm.

    670nm red laser pointers are becoming harder to find these days, and 635nm ones are becoming easier to find.
    But 650nm is by far the most common.

  16. #16

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    There's been a pinned to the top reference thread in the Night Vision section:
    Human Night Vision Preservation

    Just to make a distinction - there is true Scotopic night vision - that uses the rods only in the eyes -
    and what I tend to call dark adaption - where our eyes have adapted to the dark(er) conditions - eg: it's too dark to read by - but we can still generally still see things (ie: it's not "total" darkness) - this is very likely in most urban environments due to the sheer amount of light "pollution"/spill - where the cones of the eyes are really stll being used - any time we can see any colors we are using cones.

    When cones are used it is not true Scotopic night vision -to preserve this "dark adaption" - what is needed is just a light that disturbs this dark adaption the least.

    The real problem with red for many people is that we do not focus or see well under red light - it is one of the worst lights to see/read a regular (non-astronomy) map by - so to see reasonably well by red one tends to need a brighter red light - which in turn floods/shocks the cones, this defeats the purpose of minimal disturbance.

    Color choice in lights - for non-Scotopic dark adaption is probably down to how dim a light one can still see by - and personal choice.

    For example I can't offer references or scientific evidence -
    but I personally see well by dim yellow/amber light - it seems to give me good definition and contrast - I have even walked unlit countryside/farm outdoors by a yellow Photon.... so for me a dimmish yellow LED is a good general purpose light for me to preserve whatever dark adaption I have acquired and still see reasonable well
    - but as always YMMV

  17. #17

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    I guess I've lurked here long enough. Since one of my pages was mentioned here. Night Vision - The Red Myth Thanks spotlight. Quickbeams must of gotten bored early on since his points, to some extent, are covered on my page. However red does bleach rhodopsin. True night vision is very iffy and may not be what many really want. My page was based not only on months of research but experiments (not real scientific) on the nearest subject - me. I suggest that others try it. Three LEDs. White, blue-green (stoplight green 505nm), and deep-red (I used one that centered on 700nm, bulk of light emitted must be longer than 650nm). I suggest a resistor to limit the max. current tied to one end of a 2 Mohm or larger pot. The other end tied to the other end of the power and the correct end of the LED and the other leg of the LED tied to the wiper. Remember it takes a long time to become fully dark adapted. But you may be surprised how little light you need to sense movement.

  18. #18
    Flashaholic* Quickbeam's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    gebaltzell,

    [ QUOTE ]
    Quickbeams must of gotten bored early on since his points, to some extent, are covered on my page.

    [/ QUOTE ]

    Actually, I read the whole article, we just agree on several points. That's a good thing!

    If you have an academic reference to your statement that red does bleach rhodopsin I would be very interested in seeing it. All of my past research indicated that red did not bleach rhodopsin. I've been out of the loop for a while, so if there was more recent formal research on the subject which refutes this information, I'd be grateful for a reference so I can go to the university and look up the papers. Thanks!

  19. #19
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Comment/Question to all: most of the discussions on night vision concentrate on the back of the eye (the rods and cones). What about the iris at the front of the eye? What triggers it's contracting when light gets brighter? What's the mechanism involved and does color play a role here as well?

  20. #20

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Took me awhile to find one of them again but curve for rod spectural sensitivity can be found in "Advances in Photoreception: Proceedings of a Symposium on Frontiers of Visual Science" (1990) the chap. "Photosensitivity of Primate Photoreceptors" by Julie L. Schnapf page 34

    The question about the iris reminds me that I recently read that this is controlled by the cones even at levels were the rhodopsin was thought to be fully bleached. Unfortunately I didn't bookmark it. Did anyone else see it?

  21. #21

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Here's a quote from
    USAF Flight Surgeon's Guide: Chapter 8
    (about 2/3 down the page under the heading "Night Vision")

    QUOTE:
    Enhancing and Maintaining Dark Adaptation: For maximum utilization of scotopic vision, 20 to 30 minutes are required, in total darkness, to attain satisfactory dark-adaptation. A more practical alternative is to have the aircrew members wear red goggles to facilitate dark adaptation. Red goggles can be worn in normal illumination and do not interfere significantly with the ability to read maps, charts, manuals, etc. They block all light except red light, and red light does not simulate the rods, as we have seen.

    To understand why red filters can be used to achieve dark adaptation, it is necessary to examine the relative positions of the photopic and scotopic sensitivity curves in Figure 8-20. If a red filter with a cutoff at about 650 nanometers is worn, essentially no light is transmitted to the eye that can stimulate the rods. However, the cones are sensitive to the red light, and, thus, adequate visual acuity is permitted. By wearing red goggles for 30 minutes, the rods are almost fully dark adapted. Although the cones are not dark adapted, it only takes about 5 to 7 minutes, after a pilot steps into the dark, for the cones to adapt. Cone adaptation is relatively unimportant, since they are incapable of functioning in starlight illumination. There are, however, some drawbacks to wearing red goggles. For example, when reading maps, all markings in red ink on a white background may be invisible. In addition, red light creates or worsens near point blur in the pre-presbyopic or presbyopic pilot, as red light comes to a focus behind the retina and requires more accommodation to bring it into focus.

    Dark adaptation of the rods develops rather slowly over a period of 20 to 30 minutes, but it can be lost in a second or two upon exposure to bright lights. The night flyer must, therefore, be taught to avoid bright lights. Also, the instrument panel must be kept illuminated at the lowest level consistent with safe operation, and the flyer must avoid looking at flares, after-burner flames, or gun flashes. If light must be used, it should be as dim as possible and used for the shortest possible period.

    Dark adaptation is an independent process in each eye. Even though a bright light may shine in one eye, the other will retain its dark adaptation, if it is protected from the light. This is a useful bit of information, because a flyer can preserve dark adaptation in one eye by simply closing it.

    Cockpit Illumination: The use of red light (wavelength greater than 650 nanometers) for illumination of the cockpit is desirable, because it, like red goggles, does not affect dark adaptation. Red cockpit lighting has been traditional since World War II. The intent was to maintain the greatest rod sensitivity possible, while still providing some illumination for central foveal vision. However, red cockpit lighting did create some near vision problems for the pre-presbyopic and presbyopic aviators. With the increased use of electronic and electro-optical devices for navigation, target detection, and night vision, the importance of the pilot's visual efficiency within the cockpit has increased and new problems have been created. Low intensity, white cockpit lighting is presently used to solve those problems. It affords a more natural visual environment within the aircraft, without degrading the color of objects. Blue-green cockpit lighting is used in aircraft in which night-vision devices are used because, unlike the human eye, these devices are not sensitive to light at that end of the visual spectrum. In addition, blue-green light is the easiest for accommodative focus and is seen by the rods more readily than any other color. It is not seen as blue-green, however, but only as light. However, the enemy can easily see a blue-green light, under scotopic conditions, in any position of his peripheral field, whereas a low intensity red light would be invisible unless viewed directly.
    UNQUOTE


    Please see the CPF thread in Night Vision -
    Human Night Vision Preservation

  22. #22

    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Also from chap. 8 (from the main army site )
    8-33. The retinal rods are least affected by the wavelength of a dim red light. Figure 8-11 compares rod and cone cell sensitivities. Because rods are stimulated by low ambient light levels, red lights do not significantly impair night vision if the proper techniques are used. To minimize the adverse effect of red lights on night vision, crew members should adjust the light intensity to the lowest usable level and view instruments for only a short time.

    8-36. When exposed to bright sunlight for prolonged periods, aircrew members should wear military-issued, neutral-density sunglasses (ND-15) or equivalent filter lenses when anticipating a night flight. This precaution minimizes the negative effects of sunlight (solar glare) on rhodopsin production, which maximizes the rate of dark adaptation and improves night vision sensitivity and acuity.

    Red goggles are covered in 8-37

    This was one of my sources when I created Night Vision - The Red Myth

    I think my main point is that red is only real useful a very-very low levels and at a very long hue. It mostly applies to fighter pilots and nebula watchers. For most people a fully adjustable white is the best choice though blue-green has some advantages if you are trying to light something just to be seen. In all cases it is the intensity even more than the color.

  23. #23
    Flashaholic* flownosaj's Avatar
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    Default Re: True Red-Arc AAA vs CMG Infinity as cockpit li

    Not too sure about the flight maps out there, but the military has "red-light readable" maps (noted at the bottom of the map) that are designed to be read with the standard red filtered flashlight.


    -Jason

  24. #24
    Flashaholic* hank's Avatar
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    Default Re: True Red .... check the PALight

    I just got in a couple of PALights,

    https://www.palights.com/Detail/pallights.cfm

    two of them red for night camping/stargazing -- and am very happy with the one called "Selector" which starts off at the lowest brightness. If the button's held down it steps up six levels, quickly but slow enough to stop where you want. If the button's briefly poked it goes "off" (into an extremely dim find-me-in-the-dark mode). It's a simple wide beam, at least the red one is.

    The second PALight is their new "e-lite" -- same size, same 9-volt battery, rubber housing, but with a little wire hanger loop, and a simple plastic magnifying-lens in the space over the LED. Seems like the same LED but a brighter driving circuit, maybe. Nice rich red, two levels (starts bright, next click is dim, then a 1/second very bright red (I'd use it for changing a tire by the roadside in the dark); after that a slow, very distinct SOS that would be ideal for setting out next to a hole before I fell into it or other find-me-sometime-this-month kind of emergency.

    I'd also looked at and may yet buy the Rigel Systems (rigelsys.com) rotary-dial-dimmer red astronomy light.

    These all are brighter than the CMG light (and I got off on this tangent while looking for a true-red Arc AAA, after getting several very nice narrow-beam but in my eyes definitely orange instead, either mislabeled or else using LEDs that were at the wrong end of the reddish-kinda-sorta range for me.

    Glad to see the red-LED question still open. I'm still looking for perfection.

  25. #25
    Flashaholic RadarGreg's Avatar
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    Default Re: True Red .... check the PALight

    Flownosaj, you are right about the military maps being red light readable. They do a trick when they print them up by using an ink that isn't a true red, but rather a mix of a bit of brown and red. The result is that the reds on the maps look red under normal light, but are also visible under a red light as well.

  26. #26
    Flashaholic* flownosaj's Avatar
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    Default Re: True Red .... check the PALight

    Greg--what about the flight maps for our pilot friends? Seems to make sense to make them red light readable knowing that the pilots would need to preserve night vision in the cockpit as well...If they don't, is there any reason why?


    -Jason

  27. #27
    Flashaholic RadarGreg's Avatar
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    Default Re: True Red .... check the PALight

    I'd imagine any map that is sold as "Red Light Readable" or printed with similar wording would use the same procedure as the military maps. There is a company I believe called Jeppesen that makes pilot maps. They probably use an off-red ink so the red parts of the charts don't wash out. As a side note, if you use a blue-green filter for maps, you can end up not seeing the blue bodies of water on the military maps too. Not a pleasant thing to happen if you are near a swampy area, hehe.

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