vignetting control on Nikkor AF 20mm f2.8 with a cokin filter holder

Hi all,

I use a Sign-Ray Grad ND on a modified cokin filter holder. I sawed

off the outler filter holding part and left the inner one which is

the closest to a lens. Hence I can't stack two filters but only one.

Then I also sawed off upper and bottom 1/3 of the inner holding part

to minimize possible vignetting.

Without modification, I used to get slight vignetting on my AF

Nikkor 20mm f2.8D (62mm filter size, no screw-in filters on lens).

Now it is free from vignetting even I rotate my cokin holder 360

degree. Good.

Then I got greedy to use a 81A filter with the grad ND. I screwed in

a 62mm Nikon 81A which I see is quite slim, and put on the cokin

filter holder. Guess what, vignetting returned.

It appears to me that with this lens I can't avoid vignetting if I

wish to use a 81A filter (I don't even dare to use a thicker PL

filter) with a grad ND.

Here's my questions.

1. No way to avoid it with two filters stack on this particular lens?

2. Lee filter holder instead of a Cokin ?

3. would it be a solution to use a MF 20mm f4 which takes a 52mm

filter?

4. Any suggestion?

Try using gaffer's tape instead of the Cokin mount. Use two small pieces on the filter; just enough tape on the filter to hold it in place. This trick even works with lenses that take 77mm filters so you'll have plenty of glass surface on the grad filter to work with because that lens has a 62mm filter diameter.

This might be all the difference you need to use it with the 81A filter, but be careful not to scratch the Grad filter when mounting it.

I really like wide angle lenses. To avoid potential problems with vignetting using a Cokin filter rig, and particularly NDs, I opted for the Cokin P line:

http://www.cokin.fr/ico15-A.html

saw off the outermost slot on the filter holder. Should make a big difference.

I did it and it works (though I rarely use it on the 20, more on the 35 and 28).