What causes a scope to white out??

[fourinone]

Hi; I'm wondering if it is normal for a good quality scope to kind of get flooded with a lot of white light or even looks like a bright fog in the sight picture. This is most noticed at the higher power settings. I can screw on the sun shade and it takes care of the problem. I'm seeing this in my Elite 4200 4-16 and in my Nikon Tactical 2.5-10. Is this a problem also in the real high dollar scopes too. Is this what the sun shade is for? I was wondering what causes it in my mid priced scopes and what has been done to prevent it in higher quality scopes. Thanks

 

[hareng]

I have high regard for the 4200 series scopes and would not have thought it unless at extremes.
It is the light deflecting or scatering rather than passing through the lenses. Basically the better the glass polish the more light able to pass through with a couple of additional factors.
Did a quick test some years back with a big Niko an old Tasco CU, Nightforce BR and NXS, Burris Sig and a PRet Mark 4 Leupy.
Worst was the Niko by far followed closely by both Nightforces and the Tasco, Burris hardly any white out (milk bottle) whilst the PR Mark 4 showed not even the slightest sign.

 

[fourinone]

Thanks...I was beginning to wonder if I was just seeing things??? It does surprise me being all of these seem to have the same 95% light transmission glass in them. I didn't see it very much in my 12 year old Burris Sig. 8-32 scope, though it is a dark scope compared to the two that have the white out problems even while turned down to the same power settings. Thanks

 

[royinidaho]

Me think ya'll are chasing a ghost.

From my experience any scope when the sun is low in the sky and comb height is not quite right the first thing you see when you put the rifle up, and pointed in the direction of the sun is the bacteria and foreign objects on the surface of your own eye. This can be duplicated any time, but I have only noticed it in the field under the low in the sky sun position and that's the direction I'm shooting.

If it occurs "even whild turned down to the 'same' power setting indicates about a 3" sun shade would be in order.

Note: Just my experience w/whiteout.

 

[fourinone]

I've seen this same condition 90 degrees from the sun and I've seen it in my basement with plane old 100 watt light bulbs. But not with sun shade.