What does a sunshade do?

Discussion in 'General Airgun Chat' started by Dan Smith, Oct 11, 2019 at 3:17 PM.

  1. Dan Smith

    Dan Smith Active Member

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    So I have a 125mm sunshade on my Nikko - it came with it.

    I believe that sunshades prevent glare.

    having the sunshade on/off makes no difference to my field of view - so am I right in thinking that removing the sunshade will not make the image any brighter, that there is no disadvantage ( apart for a little weight ) to having the sunshade on even when there is no risk of glare?
     
  2. gdavison

    gdavison Active Member

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    Their function is to make the angle at which a bright light source just off center line in front of you will cause the image in the scope to "white out" .. As you say it prevents glare and flare which is caused by imperfections / surfaces of the various (but generally most is from the front one) glass lenses in a scope reflecting and channeling light into your eye which overloads the thing you are looking at (ie the target)

    Same with lens hoods in photography (do a google search on something like "are lens hoods really necessary"

    Second often forgot benefit is they help protect the front lens of your scope reducing dust build up and scratches

    Also worth noting if you add a aquarium like strip thermometer DON'T add it to the sun shade as being a simple tube of "open to the air" aluminum it will change temp quicker and very differently the rest of the scope
     
  3. Adam

    Adam Well-Known Member

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    They shade your lens from direct sunlight which as gdavison says overloads the light you want coming into your eye: the image of the target, and makes the image white out or flare.
     
  4. Dan Smith

    Dan Smith Active Member

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    Oo good tip I’ve got my temp strip on my sunshade !!
     
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  5. marojaz

    marojaz Active Member

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    It keeps the crap and rain drops off your expensive coated lens, and stops you forever cursing then continually wiping (abrading) the surface to maintain a clear view.
     
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  6. pbrown

    pbrown Bunghole

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    I experience glare off my Steyrs shiny barrel when the sun is high, a sunshade (section of waste pipe slipped on) the end of my Connect eliminates this.
     
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  7. DYNO DAVE

    DYNO DAVE Senior Member

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    The answer to your question is in the question , what does a sunshade do ,well it shades the sun , glad to help.
    Regards Dave
     
  8. Dan Smith

    Dan Smith Active Member

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    Thanks Dave - I also heard today that the pope was a catholic - who’d have guessed it?


    That answers the question in the title of the post I suppose.

    where would we all be without the shared knowledge of the forum?
     
  9. Cooper_dan

    Cooper_dan Well-Known Member

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    Mine does nothing 99% of the time. But when you get the sun at just the right angle, i can get a bit of white out and general reticle issues. To be honest its very rare i actually need it.
    I mostly have it on because I like how it looks
     
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  10. RobF

    RobF Administrator Staff Member

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    Lenses work better when the light entering them entered roughly down their axis. However light travels in all directions and can hit lenses from the side etc. This means that light can bounce around at unwanted angles and create unwanted effects. We see this as white out or flare. By restricting light to entering down the lens’ axis it reduces this problem.

    The length of a shade is normally restricted so it doesn’t appear in scope’s field of view and dim the image. With the high mag we use (even a 10x is high mag in camera terms) you can have a relatively long shade without seeing any negative effects. With ft mags of 10s of x you can really go silly. If you’re really bored you can work it out using the scope’s fov at the mag you want and the thickness of the shade. It will then give you the length.

    Probably the only downsides to a shade is fitting one which has a shine to the inner surface, the extra weight, and how much more sidewind they’ll catch.
     
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  11. Dan Smith

    Dan Smith Active Member

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    Thanks rob - I have my answer!
     
  12. FPoole

    FPoole Active Member

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    My old Bushnell 4200 Elite 8-32 has a 4" sunshade and it really doesn't need it. I just put it on for the newbie shooters, to wow them into thinking it's special.:D
     
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