I was just wondering, being new to LF. I have read of the need for center filters with wide angle lens, in particular for color work. I wanted to know are these filters designed for a lens focal lenght, design/brand? If so how about Fuji and Nikon lens that don't apear to have center filters made by those brands. Thanks, Ed

-- Ed Candland (ecandland@earthlink.net), April 19, 2002

Answers

Ed,

I agonized a while over whether I needed a CF for WA lenses - having just got a Schneider Super Angulon 75/5.6 at that time I sifted through the past postings on this forum (which, incidentally, you'd find useful to look through). Then I realized that for my use (landscapes on colour slide) a large number of successful high profile landscape photographers (eg. Jack Dykinga) didn't use them; they actually prefer the way a slight darkening in the corners can work for the image, similar to slightly burning in the corners on a B&W print. It works nicely when there's a bright feature near an image corner, actually holding the exposure back a little like a graduated neutral density filter does. Some LF users like CFs; that's fine. It's personal choice, and can depend on the make of your lens and your own style. CF filters need about 2 stops more exposure. Nikon lenses like the 90/4.5 and 90/8 reputedly have minimal falloff anyway on 4x5. Fuji do make CFs for their GX617 pano camera (77mm thread) which can be used. Theirs cost slightly less than the Schneider ones. My main advice: Don't buy a CF based on being told you need one. Take some photos with the lens & then decide if you need one. I haven't yet had anyone look at a landscape image and say, gee, the corners are slightly dark; though if I look really carefully I know they are... Best of luck, and enjoy LF.

-- brad cheers (bradcheers@hotmail.com), April 20, 2002.

P.S. Ed, looking at your question again, these filters ARE designed usually for specific lenses and focal lengths, although it is highly likely they can be put on another brand of lens if you just carefully match the appropriate filter with that lens' focal length. Have a look at the Schneider site - www.schneideroptics.com and you'll see a chart of filter types for specific Schneider lenses. Note that the filters are designed to be used first as opposed to stacking on top of another filter - yet they have an outer thread size even larger. eg a CF with a 67mm thread on the lens side has an 80-something mm final thread size. So that polarizer you wanted to put on the CF is even bigger and more expensive. Yet another reason why I came to forget the CF, accept that slight falloff, and learn to use it to my advantage.

-- brad cheers (bradcheers@hotmail.com), April 20, 2002.

I had a chance to compare two similar CF's in a store - Scheider III for SA 65/5.6 and IIIc for SAXL 47/5.6. These have the same inner and outer thread 67/86, but the IIIc is 2 stops whereas the III is 1.5 stops. More interestingly, the glass in the IIIc was mounted closer to the lens than in the III.

My guess is that for critical use it is important that the CF is at exactly the correct distance, otherwise there will be a bright or dark ring in the image. (Does this make sense?) Or perhaps it could necessary with a lower profile CF for the XL to avoid vignetting. /Åke

-- Ake Vinberg (ake@vinberg.nu), April 20, 2002.