splathrop wrote: Monito: What do you mean by \"hyperfocal performance\"?
[The hyperfocal distance is computable by using things like focal length, aperture, and distance, without reference to one particular lens model versus another.]
True. But lenses render sharply focused areas differently when the lens is used hyperfocally as compared to isolating focus on the same area. Focus a lens at infinity, and you get a different interpretation of sharp-at-infinity than if you focus short of infinity and stop down for hyperfocal performance. Different lenses handle that differently, and in direct comparisons the differences may be notable.
Technically, you are not \"sharp at infinity\" if you focus somewhere else. The plane of optimum focus, roughly parallel to the sensor or film, it the area that is \"in focus.\" Areas in front of and behind (if you focus closer than infinity) this plane are out of focus. DOF is a subjective construct that essentially describes how out of focus a thing can be and still be not so OOF that you notice in some particular printing or reproduction situation.
We have a great tool for \"calculating\" hyperfocal distance in modern DSLRs, at least when shooting from the tripod. Use live view. Focus on your primary subject. Press the DOF preview button, zoom in to 10x magnification and look around at various parts of your composition to see if they are in focus enough for you. No calculation necessary, and you will see the outcome of your focus and aperture choices directly.
There is no \"rendering\" going on here at all. There is not a \"different interpretation of sharp-at-infinity.\" To say that you \"use a lens hyperfocally\" is a very strange use of language, especially when coupled with \"as compared to isolating focus on the same area.\"
This is simply how lenses focus and how sharpness diminishes when objects are not at the optimum distance. It is not magical or even all that complex. You can easily try it and see it yourself.
This is the sort of \"mystification\" of things that can be understood in a straightforward way that confuses and puts off a lot of folks when it comes to photography-talk.
Aug 14, 2012 at 07:26 PM
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