eliminate reflections

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ricky1980

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Richard Wong
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how do u do that? i know CPL will work on trees etc does it work on glass metal and etc?

also i read the reflect can cause the picture to underexpose...so by dialling exposure compensation surely it will blow out a lot of details? is bracketing the answer then? then how the hell do you do it on a move car :thinking:
 
A polarising filter cuts polarised light. Blue sky is polarised, so if you angle it right, it gets darker.

Reflections are also polarised, so if you angle it right, about 35 degrees and at right angles to the reflection, it will kill them. It works on things like trees because at least some of the leaves will just happen to be at the optimum angle.

One way of getting the hang of it, it to stand at an angle to a car. Rotate the polariser and watch the reflections come and go along the side and off the bonnet and windscreen. Move about and it will shift around that 35 degrees angle.

The only thing polarisers wont work on is bare metal reflections. It's to do with light being electro-magnetic radiation and conductivity. For the same reason, I believe that in theory a polariser works slightly differently with reflections off salt water and fresh water, but since I've never managed to get both the sea and a lake in the same shot, it's hard to prove. But I just thought I'd share that piece of useless information with you; it might come up in a pub quiz.
 
thanks very much for that.

I have heard of polariser not work in metal wasn't sure if painted metal count...my brain switched off during my a-level physic class years ago...should have paid a bit more attention really
 
A circular polariser will certainly work on painted metal, I've never tried it on bare metal though.
 
ricky1980 said:
thanks very much for that.

I have heard of polariser not work in metal wasn't sure if painted metal count...my brain switched off during my a-level physic class years ago...should have paid a bit more attention really
Click to expand...

Paint is not metal ;)

It's not hard to test - just stick it on the camera and take a peek.
 
Annoys the hell out of me when windscreens also have polarized / anti-glare coatings.
 
SuperAP said:
Annoys the hell out of me when windscreens also have polarized / anti-glare coatings.
Click to expand...

Ah yes, forgot to mention that. It's toughened glass that is the problem with polarisers. You often get that mottled effect. But windscreens are laminated these days, which is fine. It's only the side windows.
 
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