Auteur: Jimmy Péguet
Date: 25-02-2006 08:40
"... When I look at old photographs from the 1920's through to around 1950 or thereabouts, it seems to me that large format image out of focus areas have a "creamy" well rounded good to look at feel about them. Some photographers I have spoken with say that this is due to residual uncorrected spherical aberrations. I now think it's something else. It's hard for me to see how an image can be critically sharp in the in focus areas and creamy smooth in the out of focus areas by optical design. There must be something else in play to be able to acheive this effect.
After performing this test, I believe I begin to understand why old photos can have those qualities. Small blade number apertures can produce rapidly changing dark to light transitions that can be perceived as "harshness". On the other hand, old lenses tend to have many many aperture blades that define a nearly round aperture shape. This is the single most important influence on out of focus area rendition. Further, I believe it is possible to duplicate this effect with modern optics by simply mounting them in multi-blade apertured shutters...."
On discute souvent du rendu en noir et blanc des optiques modernes par rapport à celui des optiques d'une bonne cinquantaine d'années. La remarque de Perez serait intéressante à discuter plus longuement.
Jimmy
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