COkin Circular polarizer filters

Hi dears,

I'm considering buying a polarizer for my tokina 20-35. I've found a

used Cokin circular pol. 72mm for 25 euros. It's a

conventional filter( i mean, for the way how you put it on the lens).

I don't know if it's the wide angle version or not.

I shot only B&W.

These are my questions:

1) is it a good filter? I've read bad comments on cokin filter.

Considering i could not spend too much for filters.

2) May it cause vignetting? Now i use an UV cokin filter i got with

the lens. It's not a wide angle filter and it does not give any

problem. Does it means that also the polarizer would work fine?

Thank you all!

Most people complaining about Cokin filters, are complaining about the rectangular types they sell. They are made from soft plastic that scratches easily and their grey graduated filters are not truely neutral in color. Certainly, there are better filters out there, but for the price, they are not so bad if you are carefull. As for the non-neutral color of the grads, if you are shooting print film or digital, this point is irrelavent. Neither of these issues effect the Cokin polarizers, since they are made of glass, and are not colored.

As to whether it will cause vignetting on the Tokina 20-35, I wouldn't know. Most polarizers are thicker than conventional filters, so they do more frequently cause vignetting than other filters. Any vignetting would most likely be confined to the very widest zoom setting.

Another issue is whether using a polarizer with a 20mm lens is a good idea anyway. Since polarizers have their most effect at 90 degrees from the light source, and the angle of view is so wide, the polarizing effect will be uneven across the image area. There are ocassional good uses for polarizers on wide lenses, but not as often as on longer lenses.