ND filter question

I was looking to buy this guy for my Tokina 11-16mm http://www.ebay.com …&hash=item5890e​7d4bb#shId and I noticed halfway down the page it says "Note:
According to the optics theorem, it is not recommended to apply this filter for wide angle lens (<24mm, 35mm film format equivalent).
Image quality may drop when focal length above 200mm" So what does this mean exactly? Will it not work at all with my lens or what?

I bet with such a cheap filter, you'd get image degradation regardless. But all variable ND-filters have trouble on wide angle lenses, as you'll eventually get cross-polarization, even with the more expensive ones - although these should retain the image quality.

Hmm I didn't know ND filters were polarizers, I always assumed it was gray tinted glass. Very interesting.

Believe them. Some of those filters rely on using two polarizers stacked to filter light. The effect is magnified on wide lenses and you get an x pattern where they cross. Skip it.

calypsob wrote in post #15210684
Hmm I didn't know ND filters were polarizers, I always assumed it was gray tinted glass. Very interesting.

Regular ND filters are. The faders rely on polarizers.

Here's my 11-16 with a Polaroid VND. No filter, 4-Stops, Near Maximum

calypsob wrote in post #15210684
Hmm I didn't know ND filters were polarizers, I always assumed it was gray tinted glass. Very interesting.

As far as I understand Variable ND filters are 2 polarizers stacked together. I've seen tutorials on do-it-yourself VND filter. You basically reverse 1 CPL glass and stack it on top of another (not reversed). Here's the link: http://www.youtube.com​/watch?v=76Z7l-p2RR0

Btw, the ebay seller is not trustworthy. Take a look at this page: https://photography-on-the.net …read.php?t=1220​090&page=9

hollis_f wrote in post #15212898
Here's my 11-16 with a Polaroid VND. No filter, 4-Stops, Near Maximum

And here's what it looks like at 400mm. VND on the right, Heliopan 10-stopper on the left.

Thanks HOllIS! I cruised the net in search of some examples with this lens and had no luck so this is perfect, glad I didn't find out the hard way.+1

morph2_7 wrote in post #15215284
As far as I understand Variable ND filters are 2 polarizers stacked together. I've seen tutorials on do-it-yourself VND filter. You basically reverse 1 CPL glass and stack it on top of another (not reversed). Here's the link: http://www.youtube.com​/watch?v=76Z7l-p2RR0

Btw, the ebay seller is not trustworthy. Take a look at this page: https://photography-on-the.net …read.php?t=1220​090&page=9

Thanks for the heads up morph. We talk about the pros and cons of chinese business transaction in my supply chain class all the time, the scammers never cease to amaze me. I might give that diy project a go on my non - wide angles. I do know that I have heard of using linear l=polarizer film to cover flash heads for macro, probably kind of the same concept.