light falloff with wide angle lensesgreenspun.com : LUSENET : Large format photography : One Thread
I've heard the the Nikkor 65mm f4 lens has a 2-stop light falloff, so that a center filter is needed. Is this true of all very wide lenses, or are some better than others in this regard? In particular, has anyone experienced this problem with the Fuji 65mm f5.6 lens? I want to get a 65mm lens, but don't want to have to use a center filter.
-- Stewart Ethier (email@example.com), December 09, 1997
I think it is an optical law (the cos^4). I've read that there are some clever (and uncommon) lens designs which can go around that, but most of the common very wide angle lenses will exhibit a large light fall-off.
-- Quang-Tuan Luong (firstname.lastname@example.org), December 09, 1997.
You may also want to consider the Schneider 72XL. It will give you a similar angle of view but, if my information is correct, light falloff is not a substantial enough problem to warrant the use of a center filter. (This is what a large format salesman has told me...I have not shot with the lens). The main drawbacks with this lens, however, are cost and a huge front element. You may want to consider renting,if possible, before purchasing.
-- Mark Windom (email@example.com), December 15, 1997.
The inverse square law (1/x^2) governs light falloff in wide angle large format lenses. These lenses have a wide enough angle of view that light passing through the edge of the lens travels much further than on-axis light. I have not heard about the Schneider 72XL lens being able to overcome this problem, but I wouldn't trust "salesspeak" unless I personally experienced it (shoot some Polaroid at the store.)
-- Ted Brownlee (firstname.lastname@example.org), December 26, 1997.
I rented and used the Nikkor 65mm f4 lens several years ago for some architectural work and it performed OK, but you'll probably see falloff with any LF wideangle. I know you don't want to use a center filter, but the Schneider filter I bought for my Schneider 90mm f8 makes a huge difference and works well on Schneider's 65mm f5.6 and 75mm f5.6. You may also get your local camera pro shop to order a "generic" center filter, which might also work well for less cost. Rent one if you can and try some tests--you'll be hooked.
-- Jim Blecha (email@example.com), December 30, 1997.