Center filter quality

[Leonard Evens]

I have been learning to use my 75 mm f/4.5 Grandagon-N lens. I work digitally after development with negative film. I planned to correct for illumination fall off digitally, and I think I've figured out how to do it. But there is always the option of using a center filter, particularly if I want to shoot transparencies. The Rodenstock filter costs at least twice as much as third party filters. Are there reasons for choosing the Rodenstock instead of one of the less expensive filters?

[Ralph Barker]

I would assume that the Rodenstock filter would more precisely match the fall-off curve of the Rodenstock lens (as would Schneider for Schneider), while the third-party filter would follow a generic curve which might differ from the lens performance. But, I might be putting too much faith in the manufacturers.

Perhaps Bob can tell us more.

[Sam Crater]

I got the Rodenstock CF you are interested in through Robert White and it was about $260 US. It did take a long time (2 or 3 months.) Can you get third party filters for less?

[Sam Crater]

I'm sorry, I read too quickly. Mine is the 65 4.5 which is smaller.

[Bob Salomon]

There is essentially no difference between the Heliopan and the Rodenstock center filters save possibly for the rims. Also the center filter for the Apo Grandagon is different then the one for the Grandagon-N. Both Heliopan and Rodenstock center filters have the same density and are more neutral in color then those from other manufacturers.

[Ellis Vener]

i've been happily using the Heliopan CF filters for several years. First rate.

[Leonard Evens]

The Heliopan 67 mm filter costs only slightly less than the Rodenstock 67 mm center filter, about $350 at B&H. There are Hoya and Marumi filters which cost substantially less. How would those do?

[Bob Salomon]

"How would those do"

First they may vignette if the front is not larger then the rear. Secondly they may vignette if their rims are thicker then the Rodenstock/Heliopan/Schneider. Lastly have you noticed that virtually everyone who answered so far uses a Heliopan/rodenstock or Schneider?

[Cesar Barreto]

Hi, Leonard.

I'm not so sure about it as I'm about some beers I've taken some moments ago. But I suppose any center-filter might be optimized for some specific lens at a specific aperture. We should consider that light fall-off changes relative to aperture, so wich is the right filter? The f/16 filter? Or maybe the f/64? Once we are free from vignetting and color neutrality, any filter may or may be not adequate. So, the question may come: is there any center-filter that could possibly over-correct light fall-off? I would hate to correct this on b&w printing! But if it comes to be partially correct, it's much better than nothing, isn't it? Well, coming back to beers, I say: good luck!

[Leonard Evens]

Thanks for all the advice. I will see how far I can get by digital manipulation. If that proves unsatisfactory, I will bite the bullet and get a Rodenstock or Heliopan center filter.