Contrast enhancing lens for focusing?

[pgk]

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In low contrast situations such as fog or mist, reducing the light levels may well cancel out the effect the marginal boost in contrast. In high contrast situations, such as snow, increasing the perceived contrast by darkening the shadowed (lit by blue skylight) areas may cause as many problems as not doing so. I see no benefit from using yellow glasses (I have some - unused) in practice and know nobody who does. It really is a myth.

[jaapv]

True. However so-called "roadview" sunglasses are efffective for the simple reason that they enhance red, making tailgate and brake lights stand out more in difficult conditions.

For skiing I find pink lenses work best in (bright) fog, giving a small increase in visibility. I use them, however, only to get down to a warm fireplace and reviving grappa as soon as possible.

Edited August 5, 2014 by jaapv

[wlaidlaw]

The problem is until scientists do proper testing to see what people really can pick out in varying visibility conditions, on a subjective basis it is impossible to distinguish between perceived additional contrast and real contrast increase. The brain’s processing of visual signals can give rise to all sorts of false perceptions. Just think of the bending pencil as you swing it between your fingers for a simple example.

 

Some air forces have done lots of testing, as the ability to pick out an object from a murky background in low visibility, can mean the difference between life or death. The US Air Force recommends neutral density in bright light and nothing else. I have no doubt some company was given a $100m contract to come up with this conclusion and would have had to provide loads of proper test data.

 

Wilson

[thighslapper]

I'm afraid that in my profession seeing anyone in tinted glasses is a stong indication of mental derangement ..... starting with conventional dark glasses under normal lighting and progressing through yellow, blue and finally red for the absolutely barking mad.....

[luchoperez]

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Edited February 26, 2022 by luchoperez

[a.noctilux]

1 hour ago, luchoperez said:

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❓

If you need one of this yellow sheet, something must be wrong on your M3 VF

and maybe this M3 needs to be recovered with new skin ?

[luchoperez]

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both jajaj

[Alberti]

On 8/3/2014 at 7:22 PM, wlaidlaw said:

I have tried putting a yellow filter over the RF secondary window image on my M8 and I found it did make RF focusing easier, particularly in very flat light. Unfortunately I only had it stuck on with blu-tak and it fell off un-noticed. I did not have another very small yellow filter (it was one of the rear element filters to go on my Zenitar 16mm Fish-Eye lens).

 

I used to use yellow glasses when I was target rifle shooting, as they were recommended by my optician and also served as safety glasses. I am far from convinced the yellow tint made any difference at all. When I had a later prescription for untinted safety glasses, my scores did not seem to deteriorate.

 

France used to insist on yellow tinted headlights, as supposedly it penetrated fog and rain better. All it did was make the headlights dimmer, a bit like the civil servant who put the law in place. Totally abandoned now.

 

Wilson

What I did was place a piece of yellow packing foil over the translucent window that provides the light for the static part of the RF-pad and the framelines. I did that on the M8. Worked great. I deliberately did not stick it on the small moving RF-window!

Edited March 3, 2022 by Alberti

[3D-Kraft.com]

This is what I am currently experimenting with (a little piece of Kapton tape):

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This is about, what you see through the rangefinder (RF not perfectly focused on purpose):

 

Edited October 13, 2024 by 3D-Kraft.com

[jaapv]

However I am happy with Walterleica’s contrast lenses.  
 

https://walterleica.com/walter-contrast-lenses/