Graduated ND filter quandry

[philippe]

He Lee, your contribution is the first one I read with this problem of the Cokin grad NDs at long focal length and it is exactly what I observed with my 100-400 IS lens. It was while waiting for sunrise in the Swiss Alps, together with another photographer. I used the 100-400, whereas he had the 35-350L lens, both also using a Cokin grad ND. He did not have the problem with the blur, that I had. When checking both filters on his lens, mine was crap, whereas his seemed ok (did not hear something about his results yet). Also was his filter much more neutral, whereas mine is slightly magenta. First I thought that mine probably got too warm once, but I could not explain when, since it is quite rarely in use. It looks as if there would be monstrous variation in the Cokin filter production.

 

I now plan to buy some Hitech replacement on my this summers trip to the US. Seems to me to be the best price-value mix after reading the lots of filter contributions here on photo.net.

 

Thanks for all this info.

 

Philippe

[lee_shively]

Well, Phillippe, just to be sure I had not gone totally insane, I pulled out that box of Cokins again and ran another test. I got the same results: all the filters cause distortion to a greater or lesser degree when used on long lenses. I just bought two Singh-Ray grads. I was actually somewhat apprehensive about buying any other plastic filters given the Cokin problem, but the Singh-Rays do not seem to cause any distortion at all. Expensive, yes, but so is a box full of Cokins I won't use anymore.