Anyone tried using an ND filter on sunny days? (1 Viewer)

whitedragon101 · Jul 5, 2018

I just took my shiny new Nikon Monarch 7 8x30 binoculars to the clifftop (thanks for those on the forum who helped with advice).

It is overcast but bright today so you can't see where the sun is. When looking at a Kestrel on the clifftop I could see the bird really well but I found the bright light from the clouds behind was uncomfortable, and I looked away after about 5 seconds. I felt eye strain afterwards. Because it is so overcast I am thinking maybe the sun was right behind those clouds behind the bird.

1) My vision is still perfect but I am still feeling a bit of the eyestrain after a couple of hours. Did I damage my eyes?

2) Has anyone tried adding ND filters to binoculars for bright days. Especially when tracking birds across the sky I'm afraid of accidentally passing near or over the sun and blinding myself

Binastro · Jul 5, 2018

Hi whitedragon,

You are probably O.K.
Hopefully there is no reduction of your acuity when reading small print.

Firstly, don't look at the sun, especially with optical aid, even if the sun is partly obscured by cloud.

Using ND filters may be counterproductive as our pupils may open up allowing infra red and UV light in as well as near blue and visible light.

If it is too bright, don't look.
Some people, I think, use polarising filters for reflections from the sea.
But basically, don't risk eyesight for momentary pleasure.

wllmspd · Jul 5, 2018

ND will cut UV and IR down as well, so don’t worry. As long as you’re not actually looking at the sun (or a reflection of it off a shiny surface, you should be fine. Get the same “will the full moon hurt my eyes in a big telescope like” query. If you want to darken the view then an ND or masking the aperure down a bit should work.

Peter

Patudo · Jul 7, 2018

A lot of my birdwatching involves scanning the sky, and on occasion - fortunately not all that often - white clouds can be glowing so brightly with reflected sunlight as to force me to scan a different sector of the sky. Clean white cloud is the best background to pick out distant high flying birds, but when they are glowing like that it becomes very taxing - and sometimes impossible - to stay with them. If an area of the sky is too bright or uncomfortable to look at, I recommend searching somewhere else. My brother uses sunglasses when scanning the sky on very bright days. I don't use them myself, possibly because most of the binoculars I use have fairly poor light transmission figures compared to modern ones.

It's probably unlikely that your eyes were actually damaged if it was so overcast you didn't know where the sun was, but if you're new to using binoculars and the conditions were trying, you would very likely feel some eyestrain. I hope you feel better soon.

PS. I've seen some photos of peregrines in the Old Harry Rocks area - would that be fairly close to you?

whitedragon101 · Jul 7, 2018

Patudo said:
A lot of my birdwatching involves scanning the sky, and on occasion - fortunately not all that often - white clouds can be glowing so brightly with reflected sunlight as to force me to scan a different sector of the sky. Clean white cloud is the best background to pick out distant high flying birds, but when they are glowing like that it becomes very taxing - and sometimes impossible - to stay with them. If an area of the sky is too bright or uncomfortable to look at, I recommend searching somewhere else. My brother uses sunglasses when scanning the sky on very bright days. I don't use them myself, possibly because most of the binoculars I use have fairly poor light transmission figures compared to modern ones.

It's probably unlikely that your eyes were actually damaged if it was so overcast you didn't know where the sun was, but if you're new to using binoculars and the conditions were trying, you would very likely feel some eyestrain. I hope you feel better soon.

PS. I've seen some photos of peregrines in the Old Harry Rocks area - would that be fairly close to you?

Thanks for the answer

Yes old Harry Rocks is very close. I am right on the clifftop on the middle part of Bournemouth Beach, I can see Old Harry from from my balcony window. Would be great to see Peregrines. (Maybe I already have but didn't know it). Do Peregrines hover like Kestrels staying in one place looking for prey on the ground?

etudiant · Jul 8, 2018

The military have been dealing with this problem for decades, which is why they provided yellow and gray filters as part of the standard kit. Producers today don't any more, because they are not that cheap and most of the time these are not needed. However, they remain an essential part of any full time observers equipment. No idea if any civilian binocular makers still offer them though.

Gijs van Ginkel · Jul 8, 2018

whitedragon101, post 1 and 5,
It seems much simpler and more versatile to me to use sunglasses instead of neutral density filters.
Gijs van Ginkel

Troubador · Jul 8, 2018

Hi Dragon

Looking into bright sunlight (never directly at the sun) causes my eyes to be dazzled. If I am looking outside through window and get dazzled and turn around to look into a dimmer room, for a time everything looks greenish (sometimes purpleish) and overexposed. This fades within a few minutes. I don't have any lingering discomfort that I would call eyestrain.

My understanding of eyestrain is that it occurs when the bino is out of collimation and the focusing muscles of your eyes get a horrendous workout as they struggle to focus an image that cannot be focused. This tires these muscles out and they can still feel tired hours later. This, I would call eyestrain.

Have a think about what you are really experiencing.

Lee

Anyone tried using an ND filter on sunny days? (1 Viewer)

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