Heliopan .45 center filter not strong enough?

[Andrew Prokos]

Hi there...I am using a Heliopan 82mm .45 center filter on my Nikkor 90mm f4.5 mounted on my 617 panoramic camera and have not been pleased so far with the results. It seems that the filter is not strong enough to compensate for the light falloff and in every exposure there is still considerable light falloff along the left/right edges. Even worse, there is a very strong color shift from a warmer yellowish center to cooler blueish edges. It is possible to correct this in Photoshop but it takes more time and effort than I would like. I am shooting with the lens stopped down at f16 or below most of the time, which should be more than enough to see the full effect of the filter. Is it simply a matter of needing a .9 CF for this lens? I was told that these are rarely used. Does anyone else with this lens have the same experience? thanks!

[Scott Walton]

I have a Fuji 6x17 with the center filter that is made for the camera... It is perfect even for chromes and is probably the reason why they charge somewhere around $400 or so for it. Take a look at some of the B+W's by Schneider. They have always been true color for me and are a bit less than the over priced Helio's.