Why no centerfilters for medium format?

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My experience with view camera lenses is that centerfilters are essential when shooting color slide film. I have been intrigued by the Mamiya M7 for some time now. I keep wondering, however, why there are no centerfilters made for the very wide angle lenses made for that system -- the 43 mm and 50 mm. Theoretically, those lenses must have the same fall off that other wide angle lenses have. Are they manufactured with some sort of center filter built into the l

-- Howard Slavitt (info@naturelandscape.com), May 23, 2000


I don't know the answer to this question, but I do own and use the 43mm lens for my Mamiya 7. I haven't noticed any severe falloff with this lens, but I routinely do edge burning when I print. It may be that the differences simply aren't that noticeable with the short focal distances of medium format, as opposed to an 11x14 or larger camera, where center filters are necessary with virtually every lens.

-- Ed Buffaloe (edbuffaloe@unblinkingeye.com), May 23, 2000.

IMHO, because these lenses aren't shiftable. I use a Zeiss SWC Biogon and haven't noticed objectionable vigneting.

(obviously you are right asking the question for non SLR lenses).

-- Dominique Cisari (cesarigd@club-internet.fr), May 23, 2000.

Try a test - take a LF camera with a 6x7 back and the Schneider 47XL lens (or similar from Rodenstock) and shoot some roll film without any camera movements. I'd guess the results would look very similar to the Mamiya 7 w/ wide angle lenses.

These MF lenses may not have a CF, but there is one 35mm-ish camera which does use CF lenses. It's the Hassleblad XPan. I remember seeing it in a camera store and thinking what a cute *little* CF it was compared to the ones used in LF.

-- Larry Huppert (Larry.Huppert@mail.com), May 23, 2000.

I tried your test. I shoot a Schneider 58 mm xl in the 6 x 9 format. Even without shift, when using color slide film, it requires a centerfilter. You can use it without one, but there's a huge improvement in quality (evenness of exposure) when you do use one.

-- Howard Slavitt (info@naturelandscape.com), May 23, 2000.


That is interesting. How does the 6 x 9 look if you crop it back to 6 x 7? Light fall-off is a function of distance from the center, so that extra cm on each side will make some difference. The type of subject your shooting will also make a difference around the perceived eveness of exposure. I highly doubt the Mamiya has a CF built-in.

-- Larry Huppert (Larry.Huppert@mail.com), May 23, 2000.

I have been intrigued by this fact too. Would the back focus design of the MF wide-angles be part of the answer?

-- Paul Schilliger (pschilliger@vtx.ch), May 23, 2000.

I believe that retrofocus designs decrease falloff, which is why most superwide 35mm lenses don't require a center filter.

-- David Goldfarb (dgoldfarb@barnard.edu), May 23, 2000.

A friend of mine has the M7 w/ 43mm lens and showed me his prints (no edge burning), and there is falloff. It's especially noticeable if you use a highly-saturated like velvia and have lots of sky. You can get third party CF's. The Contax G series rangefinders offer a 21mm biogon w/ no filter (again, some noticeable falloff), and a 16mm biogon that includes a CF (I'd guess extreme falloff). So I guess it depends on sensitive your eyes are to the falloff. Mine certainly are.

-- James Chow (dr_jchow@yahoo.com), May 23, 2000.

The Mamiya lenses are non-retrofocus designs, and the 43 is pretty much a Biogon type as used on the Hassie SWC. It's my understanding (and it may be wrong) that the apparent aperture size increases off-axis so there's less falloff.

At any rate, you can always use Heliopan center filters if you want to.

-- John Hicks (jbh@magicnet.net), May 23, 2000.

I agree with John above.... the fall off is less than expected. I use the 43mm a lot and always leave a Heliopan EW 1 stop ND filter on. Compared to other lenses, 1 stop is not a big speed price to pay. BTW, if you conatct Mamiya in Japan, they do suggest a center filter for the 43mm.... I do not use the 50mm. My other idea of why the 43mm has less fall off than expected is the image circle size... the larger the image circle the less fall off towards the center where the image frame is. If you shoot a white wall, with and with out the ND center filter, you will notice the light fall off! BTW Howard, that 43mm is the sharpest lens I ever owned, and I have a lot of them. Some pros buy that camera strictly to use that lens, and nothing else.

-- Bill Glickman (bglick@pclv.com), May 24, 2000.

I use a 45mm (a non-retrofocus design I guess) on my Pentax 67 and also noticed a slight but visible amount of fall-off that might need to be corrected by a 1 stop ND center filter. But this lens has a 82mm front thread then I decided to forget the filter!

-- Jean-Marie Solichon (jardin-exotique@monte-carlo.mc), May 24, 2000.

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