Vignetting test. Canon 17-40mm on full-frame camera and Lee 105mm Polariser

Today I'm going to test vignetting on Canon 17-40mm using full-frame camera and Lee filter system. The purpose of this test is to see how bad vignetting is when using Lee 105mm Rotating Polariser with two filter configuration.

Testing gear and settings: Canon 6D camera Canon 17-40 lens @17,20,21,22mm LCD monitor with white back-lit Tripod Wireless Remote Control 100mm Lee filter holder 77mm Lee Filter adaptor ring for wide-angle lenses 105mm Accessory Ring 105mm Rotating Polariser

Vignetting test with filter holder, two filter configuration and 105mm Rotating Polariser:

@17mm	@19mm	@20mm
@21mm	@22mm	Zoomed in corners @20mm and @21mm

Vignetting is alright at 21mm and completely disappears after 22mm, but that leaves you with "22-40mm" lens when using 105mm Rotating Polariser.

Although it's not advised to use polariser on ultra-wide lenses because it may darken the sky uneven there are plenty of scenes where it's still useful (waterfalls, for example).

If polariser is required then only option probably would  be screw-on filter or square polariser.

And one more important thing, the vignetting difference between not using filter holder at all and using filter holder with 105mm Accessory Ring on was meaningless.