Converting Sunglasses to Filters

[RandomlySet]

A rather cryptic title there

I've often wondered this, and was thinking about it again the other day. Anyway, I was driving into town with my Drone, and I got thinking - is there a way of telling what my sunglasses would be the equivalent of in ND lens filter form?

If that doesn't make sense, here is what I mean. When out and about, I'll see a scene that I think looks awesome, and then it dawns on me that I'm wearing my shades. Obviously I'd like to capture exactly what I can see, but using my camera - and no doubt a close enough ND filter that would match the darkness of my sunglasses.... I'm aware that like ND filters, sunglasses will also vary in their "darkness". So is there a way to roughly work out the "ND Rating" of your own sunglasses?

Daft question I know. Maybe it's been asked/answered before, maybe not.

 

[Alastair]

There's no need to know the ND value to use them in this way. I've used sunglasses as a convenient ND filter using a compact camera in Av mode. The camera meters on the light that passes through the shades.

 

[RandomlySet]

I'm thinking more for the drone or GoPro... If I knew what light my shades were blocking, then I may be able to guess what ND filter to use.... Or maybe I'm over analysing things.

 

[Alastair]

Your over thinking things. An ND isn't going to make a huge difference to how the scene is captured relative to how it's seen. A polarising filter would, but you'd need to think about how you'd adjust the rotation of the filter in-flight.

 

[Phil V]

Your over thinking things. An ND isn't going to make a huge difference to how the scene is captured relative to how it's seen. A polarising filter would, but you'd need to think about how you'd adjust the rotation of the filter in-flight.

This^
And the tint of your sunglasses is what makes the scene look different. An ND shouldn't alter what a scene looks like, just how long it takes to record.

 

[droj]

Your over thinking things. An ND isn't going to make a huge difference to how the scene is captured relative to how it's seen. A polarising filter would, but you'd need to think about how you'd adjust the rotation of the filter in-flight.

This^
And the tint of your sunglasses is what makes the scene look different. An ND shouldn't alter what a scene looks like, just how long it takes to record.

No, I think that you both may be over-thinking it. A scene may look different (better, in this case) to the eyes, through sunglasses, because the tones are darkened - 'enriched'. (Let's assume for this purpose that the sunglasses have a neutral tint - unlikely, I know, but let's assume it.)

In which case, no filter is required to replicate the impression - you would just lower the exposure? As in dialling in exposure compensation downwards by a stop, say. If that's possible with a GoPro?

 

[TheAndyA]

Oddly enough, I've thought about this too! My sunglasses give an orange, warm tint and I'd love to be able to apply the same effect to some of my images. I've tried the photo filters in PS, but they don't do the trick for me.

 

[Phil V]

No, I think that you both may be over-thinking it. A scene may look different (better, in this case) to the eyes, through sunglasses, because the tones are darkened - 'enriched'. (Let's assume for this purpose that the sunglasses have a neutral tint - unlikely, I know, but let's assume it.)

In which case, no filter is required to replicate the impression - you would just lower the exposure?

Nope, a scene will look 'different' through sunglasses because the tint and polarisation in the sunglasses filters different colours differently. As you say a straight ND doesn't alter colours, you could mimic ND sunglasses just by lowering the exposure, but sunglasses are rarely neutral

 

[Alastair]

Oddly enough, I've thought about this too! My sunglasses give an orange, warm tint and I'd love to be able to apply the same effect to some of my images. I've tried the photo filters in PS, but they don't do the trick for me.

A physical tinted filter doesn't just put a cast over the image, it also subtly affects transmission at different wavelengths. "Simple" PS actions and LR presets often overlook the more subtle effects. Plus, if your tinted sunglasses are also polarising you won't be able to replicate that with just a digital filter.