Counterintuitive photography interlude
Special note to those who normally read over these sorts of posts: If you read this you will know something that the vast majority of people don't, and that you would almost certainly never conclude on your own.
System Resolving PowerIn other words, when you use a lens that "outresolves" your film or digital sensor, it still helps the resolution of the overall imaging system. I only learned this recently, and still find it very counterintuitive. It seems akin to saying that you'll get a more accurate measurement to the nearest kilometer if you use a ruler graduated in millimeters.
The resolving power of a system can never exceed the lowest resolving power among the components that comprise the system. In fact, the system value is actually lower. For example, if a lens with a resolving power of 200 lines/mm were used with a film with a resolving power of 50, the combined system resolving power would be 40.
To accurately determine the resolving power of a system, use the
following equation :
1/R = 1/r1+1/r2+1/r3
(where "R" is the resolving power of the system and each "r" represents that of each component) - Fujifilm Professional Data Guide
It's easier to see how this works, I think, if you picture each component of the system as introducing its own little bit of inaccuracy—a lens with great resolving power just introduces less inaccuracy.
posted at 3:15 PM
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