Originally Posted by
Drew Wiley
Certain basics: illumination falloff comes with the territory of wide angle lens design. And the Achilles heel to just deciding to ignore falloff and not invest in a center filter is that once any significant view camera movement is applied - whether rise, tilt, shift, etc - your cone of light is off axis and the falloff itself will no longer be symmetrical in the image. In other words, you might end of with one side of the image significantly darker than the opposite side, or one corner mismatched to another. And don't blame me for complicating things. Blame God or the laws of physics instead. It is just a fact of life, optically.
And in terms of color film usage, significant density shifts do not necessarily remain color neutral, but can often induce actual hue shifts or color-crossover issues. So in that case, you can't simply dodge or burn away off-axis problems. A center filter becomes even more important. I don't want to go beyond that at the moment; but there are other potential issues too.
Any modern wide angle lens from the big four is designed to handle color film competently. But none of them should be classified as "apo" in the stricter graphics sense; but in general purpose photography they're going to be plenty good enough. Don't take books or calendars as a standard of comparison. In fact, almost no mode of color presentation other than an old fashioned slide show can due justice to hue differentiations achievable with most modern lenses.
The best way to avoid needing center filters is to use regular wide lenses instead of wide-angle ones. That works down to about 120mm for 4X5 coverage, provided you don't need strong architecture-style movements. Once you enter true wide angle territory, worse falloff and that stretched toward corners look becomes inevitable. The Super Symmar 110XL might allow a little more wiggle room with only modest falloff; but they're expensive and the earlier serial number had a serious quality control issue.
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