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| p.7 #10 · Canon 17mm f/4L TS-E Custom Filter Adapter |
I have always wanted a good way to add a polarizer to the Canon 17 TS-E, to help with water reflections, and also for improved color saturation in a variety of subjects in nature. I know that scenes with blue sky in them can be seriously affected by a polarizer on a lens this wide, but the other uses are important to me.
The new Lee filter adapter for the 17 now makes it possible to mount a 105mm polarizer, so I have evaluated that option. For me, I would not often need a graduated ND fliter combined with a polarizer, so I configured the filter holder without any provision for the 4 inch wide filters. I removed the plastic filter holder edges completely, and then mounted the 105mm metal filter adapter ring directly to the face of the holder body. This allows the mounting of screw in filters as close as possible to the front of the lens for this adapter and system. I checked first the vignetting caused by just the filter adapter edge. I then installed my B+W 105mm KSM circular polarizer, and evaluated the additional vignetting that the polarizer caused. All evaluations were done by visual inspection looking through the view finder of a 5D3 with the lens wide open. Note that stopping down this lens causes the vignetting to get slightly worse, which is I believe related to the increased depth of field.
For landscape orientation of the camera, and for shifting in the vertical direction, the edge of the holder becomes visible at about 8 mm of shift. Stopping down the lens to f22 changes the start of vingnetting to about 7mm. When the polarizer is added on the front, the edge of the polarizer becomes visible at about 2 mm of shift.
For portrait orientation of the camera, and for still shifting in the vertical direction, the edge of the holder becomes visible at about 5 mm of shift. Stopping down to f22 changes that to about 4 mm. When the polarizer is added on the front, the edge of the polarizer becomes visible at about 1.5 mm of shift.
So it looks like a 105mm circular polarizer mounted on the Lee system using this adapter, and with no filter slot included, is usable, but not with much shift available before vingnetting occurs.
The best polarizer solution with the Lee 4 inch system may well be to get a high quality 4 inch square circular polarizer, and use it on a Lee adapter set up for just one slot. I have not yet tested that kind of configuration, but it looks like the vingnetting for a single filter set up would be limited by the adapter ring, with no further limitations caused by the filter holder edge. Now I just need to buy another very expensive circular polarizer. It never ends, does it.