Lee 105mm CPL Filter Factor?

[ckkim120]

Hey all,

I recently purchased a Lee 105mm CPL (not the slim version) used. It's advertised to have 1.2-1.5 stops of reduction. However, after testing the filter against a white wall with my sekonic spot meter, I measured 1.8 stops of filtration. Is it possible that I received a fake? Can anyone else that owns the filter testify to the accuracy of the advertised filter factor?
Thanks.

[Lachlan 717]

Have you tested it against a grey card and other solid colours?

[ckkim120]

I haven't, but wouldn't it not make a difference when using a spot meter?

[Mark Darragh]

I don't have the particular Lee Polariser you mention but I have Seven5 and 4x4 CPL. With both of these filters I use a factor of two stops. YMMV

[mpirie]

Could the difference in readings be down to the colour response of the meter and the colour absorption of the filter or background?

Mike

[Lachlan 717]

I haven't, but wouldn't it not make a difference when using a spot meter?

It depends on the wavelength of the light and the filter’s ability to transmit them. So, yes. I will make a difference.

[Pfsor]

Hey all,

I recently purchased a Lee 105mm CPL (not the slim version) used. It's advertised to have 1.2-1.5 stops of reduction. However, after testing the filter against a white wall with my sekonic spot meter, I measured 1.8 stops of filtration. Is it possible that I received a fake?

Try to measure the filter factor of your other filters with your Sekonic meter. Chances are you will get a different view on your fake theory. Just MO.

[Pere Casals]

It depends on the wavelength of the light and the filter’s ability to transmit them. So, yes. I will make a difference.

In theory a good Pol/CPol is neutral regarding wavelength, transmiting all wavelengths the same, if not the Pol would change color hues. A Pol/CPol may change saturation by removing glares of a polarized light source like direct sunlight.

If we have two illumination sources of different "colors" each with also different polarization each then the filter may block different the glares of each source, but this is not because of the particular wavelengths, it's because of the polarizarions of each source.

[ckkim120]

So I tested some more surfaces/colors, and I consistently get 1.8-1.7 stops. It's not too big of a deal in terms of actual usage, I'm more concerned that I received a fake.

[Bob Salomon]

So I tested some more surfaces/colors, and I consistently get 1.8-1.7 stops. It's not too big of a deal in terms of actual usage, I'm more concerned that I received a fake.

No one is going to make fake filters!!!

Fake Rolex watches, yes. Fake Cartier, yes. Fake Louis Vuitton, yes! Fake filters, no way, no market for the trouble of making them. Especially in that size!